test(e2e): mission test — match dotted ACTIVE badge, idempotent across retries

CI run 358: the ACTIVE assertion used exact text but badge.tsx renders a
'●' dot prefix for ACTIVE variants (text is '●ACTIVE'), so it could never
match. And attempt 1's accept persisted an ACTIVE mission, leaving every
ACCEPT button disabled on retry. Drop exact matching and, when a leftover
active mission exists, assert the UI state and complete that one instead of
re-accepting.

CHANGELOG.md

@@ -1,5 +1,34 @@
 # Changelog
 
+## v0.8.0 — 2026-09-29 01:56
+- MISSIONS tab — contract generation, acceptance and completion (issue #10): the first objective loop on top of issue #9's research. The board is generated deterministically from the save seed; one mission is ACTIVE at a time; completion is checked after every jump and scan and grants its reward into the cargo hold.
+- New table (`lib/db/schema.ts` + DDL): `missions` (id/save_id/type/description/target_system_id/condition_kind/progress_target/progress/reward_kind/reward_qty/state). Seeded on new game AND as backfill step v6 — same pattern as tech; saves created by older code get their board on first read. `SCHEMA_VERSION` 5 → 6.
+- Pure mission model (`lib/game/missions.ts`, no save.ts import — the completion hooks are called FROM save.ts, one-way): three types — DELIVER (jump to a target system), EXPLORE (scan N = 2–4 bodies), FIND (haul in an item of one kind). `missionRng(seed, turn)` anchors generation exactly like world expansion does; every action costs exactly one turn, so the stream never repeats. The board is always topped up to ≥3 AVAILABLE after every action (`topUpMissionBoard`, idempotent); DELIVER targets only discovered non-current systems (none on a fresh game → initial contracts are EXPLORE/FIND).
+- Acceptance & completion: `acceptMission` — 409 while another mission is ACTIVE or the contract isn't AVAILABLE, costs one turn like every other action and writes an event. `checkMissionCompletion` runs inside jumpToSystem/explorePlanet before persist (one atomic write): DELIVER completes on arrival at its target system, EXPLORE counts scans (capped), FIND completes when a haul contains its kind; completion marks DONE, grants the reward as one neutral 'MISSION REWARD' row of the mission's kind (spenders consume by kind only) and writes an event.
+- New endpoints: `GET /api/missions` → `[{id,type,description,targetSystemId,conditionKind,progressTarget,progress,rewardKind,rewardQty,state}]`; `POST /api/missions/{id}/accept` → fresh board (400 non-integer id, 404 unknown, 409 wrong state / active conflict). OpenAPI spec in code updated (12 → 14 paths) with the Mission schema.
+- MISSIONS tab now renders REAL data: one card per contract — type title + state badge (AVAILABLE/ACTIVE/DONE), CONTRACT // #id line, objective, reward line and an EXPLORE-only progress line; ACCEPT is enabled only when the contract is AVAILABLE and nothing else is ACTIVE, each response applied directly (no polling). Placeholder encounter content removed.
+- Tests: unit — deterministic generation per type + reward range over 200 draws, same-stream determinism, DELIVER target selection / null on a fresh game, top-up idempotency + MIN_AVAILABLE floor, v6 backfill on pre-mission saves (idempotent), accept validation (404/409) + turn + event + re-top-up, per-type completion through real jump/explore actions incl. wrong-system non-completion and reward accumulation into one row; e2e — MISSIONS tab accepts a contract via the UI (card flips ACTIVE, button disables), completes it via API (scan loop for EXPLORE/FIND, BFS jump path for DELIVER) and asserts DONE + the reward landed in the hold, plus the mission board survives the mid-run container restart.
+
+## v0.7.0 — 2026-09-29 00:38
+- SKILL TREE tab — technology research unlocks (issue #9): the second spend-side loop on top of issue #8's ship systems. Researching a tech costs inventory items + a turn and its unlock effect then gates or raises ship actions, so the two tabs interlock: researching WEAPONS SYSTEMS is what makes building WEAPONS possible at all.
+- New table (`lib/db/schema.ts` + DDL): `tech` (id/save_id/slug/name/cost_kind/cost_qty/prerequisites/effect/researched, UNIQUE(save_id,slug)). Definitions are seeded from the pure module on new game AND as backfill step v5 — same pattern as ship_systems; saves created by older code get the tree on first read. `SCHEMA_VERSION` 4 → 5.
+- Pure tech model (`lib/game/tech.ts`, no DB imports — imported by both server and UI so research/cap/gate logic can't drift): six techs in two short chains (WEAPONS SYSTEMS → PLASMA CANNON, REACTOR OVERCLOCK → FUSION CORE) plus four roots. Effects: WEAPONS SYSTEMS gates building WEAPONS; the other five raise one system type's UPGRADE level cap or EXPAND capacity cap by 2–3 over the base caps. Helpers compute per-tech state (RESEARCHED / AVAILABLE / LOCKED + missing prereq names), effective caps and build gates from a set of researched slugs.
+- Research action (`lib/game/research.ts`): `getTechState` → the full tree with per-save state; `researchTech` validates prerequisites (409, naming what is missing) and the cost against the cargo hold (422), spends it through the same oldest-row-first path as ship actions, marks the tech researched, costs a turn and writes an event.
+- Ship-action gating (`lib/game/ship.ts`): `buildSystem('WEAPONS')` now 409s "requires the WEAPONS SYSTEMS tech" until it is researched; UPGRADE/EXPAND use the effective caps from researched techs, so a raised cap re-enables buttons that were capped.
+- New endpoints: `GET /api/tech` → `[{id,slug,name,costKind,costQty,prereqs,effect,state,missingPrereqs}]`; `POST /api/research {techId}` → fresh tech tree state (400 malformed body, 404 unknown id, 409 already researched / prereq missing, 422 insufficient hold). OpenAPI spec in code updated (12 paths).
+- SKILL TREE tab now renders REAL data: one card per tech with a state badge, cost line, UNLOCKS line and — when locked — the blocking prerequisite(s); RESEARCH is enabled only for AVAILABLE techs whose cost the cargo hold can pay, and each response is applied directly (no polling). SHIP SYSTEMS cards pick up the same pure helpers: effective caps drive UPGRADE/EXPAND disabling and gated builds show a red `REQUIRES // <TECH>` line with BUILD NEW disabled. Placeholder skill cards removed; MissionControl owns both states so the tabs stay in sync.
+- Tests: unit — tree seeding on new game + v5 backfill (deterministic, idempotent), per-tech state incl. locked-with-missing-prereq names, research cost validation with no mutation on failure, exact oldest-first deduction + turn + event + persistence, prereq chain unlock, WEAPONS build gated 409 → succeeds after research, REACTOR upgrade cap raised by REACTOR OVERCLOCK; e2e — SKILL TREE tab researches WEAPONS SYSTEMS via the UI (card flips to RESEARCHED) and the previously-disabled BUILD NEW on WEAPONS becomes enabled and builds, plus tech state survives the mid-run container restart.
+
+## v0.6.0 — 2026-09-28 23:46
+- SHIP SYSTEMS tab — expand / upgrade / build ship systems + save backfill plumbing (issue #8): the first spend-side game loop on top of issue #7's crew, plus a root-cause fix for saves created by older code lacking data newer code seeds. Single-player, no auth, by design.
+- Backfill plumbing: `schema_version` INTEGER added to `saves` (NULL = v1). `ensureSave` now runs ordered IDEMPOTENT backfill steps for anything below current — v2: every system without planets gets its generated bodies (same `(seed, systemId)` derivation as fresh generation), v3: starting crew if no rows. New games get the current version directly. `lib/db/client.ts` open() carries an idempotent `ALTER TABLE ... ADD COLUMN` guard for files created before the column existed — old saves open fine and backfill on first read, so DB wipes are no longer needed when deploying new versions.
+- New table (`lib/db/schema.ts` + DDL): `ship_systems` (id/save_id/type/level/capacity, UNIQUE(save_id,type)). `built` is derived, not stored — level > 0 means built; unbuilt rows sit at level/capacity 0. Starting ship seeded on new game AND as backfill step v4: core types (HULL, REACTOR, LIFE SUPPORT, NAV COMPUTER, COMMS ARRAY) built at base values, WEAPONS unbuilt until a build action.
+- Cost model (`lib/game/ship-costs.ts`, pure — imported by both the API and the UI so affordability can't drift): UPGRADE costs `level` units of any resource (capped at MAX_LEVEL 5), EXPAND costs `capacity` units of any resource (capped at MAX_CAPACITY 10), BUILD costs a flat 3 parts. Consumption takes from the oldest cargo row of the required kind first, deleting rows that hit zero; an unaffordable action mutates nothing.
+- Ship actions (`lib/game/ship.ts`): `upgradeSystem` / `expandSystem` / `buildSystem` — validate (404 unknown id/type, 409 not built / already built / at cap, 422 insufficient inventory), spend the cost, bump level/capacity or build at base values, cost one turn and write an event each.
+- New endpoints: `GET /api/ship` → `{systems:[{id,type,level,capacity,built}],inventory,turn}`; `POST /api/ship/upgrade {systemId}`, `POST /api/ship/expand {systemId}`, `POST /api/ship/build {type}` — each returns the fresh ship state. OpenAPI spec in code updated (10 paths).
+- SHIP SYSTEMS tab now renders REAL data: cards show type + level/capacity with UPGRADE / EXPAND buttons per built card and BUILD NEW for unbuilt types, disabled when unaffordable or capped; each action's response is applied directly (no polling). Left column mirrors live state too — the SHIP SYSTEMS panel lists every system with its status/level/capacity + an N ONLINE badge, and VESSEL METRICS bars are driven by real values (hull/reactor from system levels, crew roster vs a cap of 6). Placeholder constants for both removed; other tabs keep theirs until their issues land.
+- Tests: unit — backfill upgrades a hand-built v1 save in place (deterministic vs fresh generation, idempotent), starting ship seeding, cost validation with no mutation on failure, exact oldest-first inventory deduction, level/capacity caps, build-once, turn + event per action; e2e — SHIP SYSTEMS tab performs one affordable UPGRADE/BUILD via the UI after a bounded scan loop until something is affordable (asserting card + left column reflect it), and ship state survives the mid-run container restart.
+
 ## v0.5.0 — 2026-09-28 22:51
 - CREW tab — crew roster with good/bad traits (issue #7): the ship's people on top of issue #6's exploration loop. Single-player, no auth, by design. Display + arrival only — no dismiss/assign actions yet.
 - New table (`lib/db/schema.ts` + DDL in `lib/db/client.ts`): `crew` (id/save_id/name/role/trait_good/trait_bad/origin). Origin is 'STARTING CREW' for the seeded crew or '<planet>, <system>' for members found while exploring.

app/api/missions/[id]/accept/route.ts

@@ -0,0 +1,24 @@
+import { getGameDb } from '@/lib/db/client'
+import { ensureSave } from '@/lib/game/save'
+import { acceptMission, MissionError } from '@/lib/game/missions'
+
+// Accept an AVAILABLE mission — it becomes the single active one. Costs a turn; returns the fresh board.
+export async function POST(_req: Request, ctx: { params: Promise<{ id: string }> }) {
+  const db = await getGameDb()
+  await ensureSave(db) // acceptMission assumes a save exists
+
+  const { id } = await ctx.params
+  const missionId = Number(id)
+  if (!Number.isInteger(missionId)) {
+    return Response.json({ error: 'mission id must be an integer' }, { status: 400 })
+  }
+
+  try {
+    return Response.json(await acceptMission(db, missionId))
+  } catch (err) {
+    if (err instanceof MissionError) {
+      return Response.json({ error: err.message }, { status: err.status })
+    }
+    throw err
+  }
+}

app/api/missions/route.ts

@@ -0,0 +1,10 @@
+import { getGameDb } from '@/lib/db/client'
+import { ensureSave } from '@/lib/game/save'
+import { getMissions } from '@/lib/game/missions'
+
+// The full mission board for the single active save; auto-initializes on first hit.
+export async function GET() {
+  const db = await getGameDb()
+  await ensureSave(db) // top-up inside getMissions assumes a save exists
+  return Response.json(await getMissions(db))
+}

app/api/research/route.ts

@@ -0,0 +1,27 @@
+import { getGameDb } from '@/lib/db/client'
+import { ResearchError, researchTech } from '@/lib/game/research'
+
+// Research one tech. Body: { "techId": number }. Costs inventory items + a turn; returns the fresh tech tree state.
+export async function POST(req: Request) {
+  let body: unknown
+  try {
+    body = await req.json()
+  } catch {
+    return Response.json({ error: 'Invalid JSON body' }, { status: 400 })
+  }
+
+  const techId = (body as { techId?: unknown }).techId
+  if (typeof techId !== 'number' || !Number.isInteger(techId)) {
+    return Response.json({ error: 'techId must be an integer' }, { status: 400 })
+  }
+
+  try {
+    const db = await getGameDb()
+    return Response.json(await researchTech(db, techId))
+  } catch (err) {
+    if (err instanceof ResearchError) {
+      return Response.json({ error: err.message }, { status: err.status })
+    }
+    throw err
+  }
+}

app/api/ship/build/route.ts

@@ -0,0 +1,28 @@
+import { getGameDb } from '@/lib/db/client'
+import { ShipError, buildSystem } from '@/lib/game/ship'
+
+// Build an unbuilt ship system type at base values. Body: { "type": string }.
+// Costs inventory items + a turn; returns the fresh ship state.
+export async function POST(req: Request) {
+  let body: unknown
+  try {
+    body = await req.json()
+  } catch {
+    return Response.json({ error: 'Invalid JSON body' }, { status: 400 })
+  }
+
+  const type = (body as { type?: unknown }).type
+  if (typeof type !== 'string' || type.length === 0) {
+    return Response.json({ error: 'type must be a non-empty string' }, { status: 400 })
+  }
+
+  try {
+    const db = await getGameDb()
+    return Response.json(await buildSystem(db, type))
+  } catch (err) {
+    if (err instanceof ShipError) {
+      return Response.json({ error: err.message }, { status: err.status })
+    }
+    throw err
+  }
+}

app/api/ship/expand/route.ts

@@ -0,0 +1,28 @@
+import { getGameDb } from '@/lib/db/client'
+import { ShipError, expandSystem } from '@/lib/game/ship'
+
+// Raise a built ship system's capacity by one (capped at max capacity). Body: { "systemId": number }.
+// Costs inventory items + a turn; returns the fresh ship state.
+export async function POST(req: Request) {
+  let body: unknown
+  try {
+    body = await req.json()
+  } catch {
+    return Response.json({ error: 'Invalid JSON body' }, { status: 400 })
+  }
+
+  const systemId = (body as { systemId?: unknown }).systemId
+  if (typeof systemId !== 'number' || !Number.isInteger(systemId)) {
+    return Response.json({ error: 'systemId must be an integer' }, { status: 400 })
+  }
+
+  try {
+    const db = await getGameDb()
+    return Response.json(await expandSystem(db, systemId))
+  } catch (err) {
+    if (err instanceof ShipError) {
+      return Response.json({ error: err.message }, { status: err.status })
+    }
+    throw err
+  }
+}

app/api/ship/route.ts

@@ -0,0 +1,8 @@
+import { getGameDb } from '@/lib/db/client'
+import { getShipState } from '@/lib/game/ship'
+
+// The ship's systems + cargo hold + turn; auto-initializes on first hit.
+export async function GET() {
+  const db = await getGameDb()
+  return Response.json(await getShipState(db))
+}

app/api/ship/upgrade/route.ts

@@ -0,0 +1,28 @@
+import { getGameDb } from '@/lib/db/client'
+import { ShipError, upgradeSystem } from '@/lib/game/ship'
+
+// Level up a built ship system by one (capped at max level). Body: { "systemId": number }.
+// Costs inventory items + a turn; returns the fresh ship state.
+export async function POST(req: Request) {
+  let body: unknown
+  try {
+    body = await req.json()
+  } catch {
+    return Response.json({ error: 'Invalid JSON body' }, { status: 400 })
+  }
+
+  const systemId = (body as { systemId?: unknown }).systemId
+  if (typeof systemId !== 'number' || !Number.isInteger(systemId)) {
+    return Response.json({ error: 'systemId must be an integer' }, { status: 400 })
+  }
+
+  try {
+    const db = await getGameDb()
+    return Response.json(await upgradeSystem(db, systemId))
+  } catch (err) {
+    if (err instanceof ShipError) {
+      return Response.json({ error: err.message }, { status: err.status })
+    }
+    throw err
+  }
+}

app/api/tech/route.ts

@@ -0,0 +1,8 @@
+import { getGameDb } from '@/lib/db/client'
+import { getTechState } from '@/lib/game/research'
+
+// The full tech tree with per-save state (RESEARCHED / AVAILABLE / LOCKED + missing prereqs). Auto-initializes on first hit.
+export async function GET() {
+  const db = await getGameDb()
+  return Response.json(await getTechState(db))
+}

components/mission-control.tsx

@@ -2,9 +2,6 @@
 
 import { useEffect, useState } from 'react'
 import { Badge } from '@/components/ui/badge'
-import { Alert, AlertDescription, AlertTitle } from '@/components/ui/alert'
-import { Button } from '@/components/ui/button'
-import { Card, CardContent, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
 import { Panel, PanelContent, PanelHeader, PanelTitle } from '@/components/ui/panel'
 import { Progress } from '@/components/ui/progress'
 import { StatCard } from '@/components/ui/stat-card'
@@ -13,12 +10,20 @@ import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
 import { Terminal, type TerminalLine } from '@/components/ui/terminal'
 import { CrewPanel } from '@/components/crew-panel'
 import { LocalSystemPanel } from '@/components/local-system'
+import { MissionPanel } from '@/components/missions'
+import { ShipSystemsPanel } from '@/components/ship-systems'
+import { SkillTreePanel } from '@/components/skill-tree'
 import { WorldMapPanel } from '@/components/world-map'
+import { CREW_CAPACITY } from '@/lib/game/ship-costs'
+import type { CrewDto } from '@/lib/game/save'
+import type { ShipState } from '@/lib/game/ship'
+import type { TechDto } from '@/lib/game/tech'
 
 // Interface base: layout + visual treatment rebuilt from the scificn-ui Mission Control
 // showcase (src/app/_pages/showcase/mission-control-content.tsx in baxy5/scificn-ui). The
-// WORLD MAP, LOCAL SYSTEM and CREW tabs render live data (/api/world, /api/system, /api/crew);
-// the other tabs keep placeholder content until their own issues land. Single player, no auth, by design.
+// WORLD MAP, LOCAL SYSTEM, CREW, SHIP SYSTEMS, SKILL TREE and MISSIONS tabs render live data
+// (/api/world, /api/system, /api/crew, /api/ship, /api/tech, /api/missions); the EVENT LOG tab
+// keeps placeholder content until its own issue lands. Single player, no auth, by design.
 
 function useNarrow(threshold = 900): boolean {
   const [narrow, setNarrow] = useState(
@@ -38,29 +43,6 @@ function now(): string {
 
 // ── Placeholder content (no game logic — real values land with the turn engine) ──
 
-const shipSystems: SystemEntry[] = [
-  { name: 'REACTOR', status: 'ACTIVE', detail: '94.2%' },
-  { name: 'LIFE SUPPORT', status: 'ACTIVE' },
-  { name: 'NAV COMPUTER', status: 'SCANNING' },
-  { name: 'WEAPONS', status: 'OFFLINE' },
-  { name: 'COMMS', status: 'ACTIVE' },
-]
-
-const shipSystemCards = [
-  { name: 'REACTOR', level: 'LV 2', status: 'ACTIVE' as const, actions: ['EXPAND', 'UPGRADE'] },
-  { name: 'LIFE SUPPORT', level: 'LV 1', status: 'ACTIVE' as const, actions: ['EXPAND', 'UPGRADE'] },
-  { name: 'NAV COMPUTER', level: 'LV 3', status: 'SCANNING' as const, actions: ['EXPAND', 'UPGRADE'] },
-  { name: 'WEAPONS', level: 'OFFLINE', status: 'OFFLINE' as const, actions: ['BUILD NEW'] },
-  { name: 'COMMS ARRAY', level: 'LV 1', status: 'ACTIVE' as const, actions: ['EXPAND', 'UPGRADE'] },
-]
-
-const skillCards = [
-  { name: 'ADVANCED FUSION CORE', unlocks: 'REACTOR LV 4 + OVERCLOCK', state: 'AVAILABLE' as const },
-  { name: 'HULL PLATING SCHEMATICS', unlocks: 'BUILD ARMOR BAY MODULES', state: 'AVAILABLE' as const },
-  { name: 'CREW TRAINING PROTOCOLS', unlocks: 'RETRAIN CREW TRAITS', state: 'LOCKED' as const },
-  { name: 'JUMP DRIVE TUNING', unlocks: 'SHORTER JUMP COOLDOWN', state: 'LOCKED' as const },
-]
-
 const encounters = [
   { name: 'DERELICT FREIGHTER', when: 'T-07:14', id: '#E-102' },
   { name: 'PIRATE SKIRMISH', when: 'T-22:40', id: '#E-103' },
@@ -89,6 +71,46 @@ const logLines: TerminalLine[] = [
 export function MissionControl() {
   const narrow = useNarrow()
   const [tick, setTick] = useState(0)
+  // Ship state is owned here (not in the tab panel) so the left column mirrors ship actions
+  // immediately; the SHIP SYSTEMS tab applies each action's response via setShip. Crew count
+  // feeds the roster bar — refetched on page load, like the other panels.
+  const [ship, setShip] = useState<ShipState | null>(null)
+  const [techs, setTechs] = useState<TechDto[] | null>(null)
+  const [crewCount, setCrewCount] = useState<number | null>(null)
+
+  useEffect(() => {
+    let cancelled = false
+    fetch('/api/ship')
+      .then(async (res) => {
+        if (!res.ok) throw new Error(`HTTP ${res.status}`)
+        return (await res.json()) as ShipState
+      })
+      .then((s) => {
+        if (!cancelled) setShip(s)
+      })
+      .catch(() => {}) // left column + tab keep their loading state on failure
+    fetch('/api/tech')
+      .then(async (res) => {
+        if (!res.ok) throw new Error(`HTTP ${res.status}`)
+        return (await res.json()) as TechDto[]
+      })
+      .then((t) => {
+        if (!cancelled) setTechs(t)
+      })
+      .catch(() => {})
+    fetch('/api/crew')
+      .then(async (res) => {
+        if (!res.ok) throw new Error(`HTTP ${res.status}`)
+        return (await res.json()) as CrewDto[]
+      })
+      .then((c) => {
+        if (!cancelled) setCrewCount(c.length)
+      })
+      .catch(() => {})
+    return () => {
+      cancelled = true
+    }
+  }, [])
 
   useEffect(() => {
     const id = setInterval(() => setTick((t) => t + 1), 1000)
@@ -97,6 +119,10 @@ export function MissionControl() {
 
   const timeStr = new Date().toLocaleTimeString('en-GB', { hour12: false })
 
+  // Slugs of the researched techs — drives the effective caps + build gates in the SHIP SYSTEMS
+  // tab via the same pure helpers the API enforces (lib/game/tech.ts).
+  const researchedSlugs = new Set((techs ?? []).filter((t) => t.state === 'RESEARCHED').map((t) => t.slug))
+
   return (
     <div
       style={{
@@ -257,11 +283,25 @@ export function MissionControl() {
               <PanelHeader>
                 <PanelTitle>SHIP SYSTEMS</PanelTitle>
                 <div style={{ marginLeft: 'auto' }}>
-                  <Badge variant="ACTIVE">4 ONLINE</Badge>
+                  <Badge variant={ship && ship.systems.some((s) => s.built) ? 'ACTIVE' : 'OFFLINE'}>
+                    {ship ? `${ship.systems.filter((s) => s.built).length} ONLINE` : '—'}
+                  </Badge>
                 </div>
               </PanelHeader>
 
-              <StatusGrid systems={shipSystems} />
+              {ship ? (
+                <StatusGrid
+                  systems={ship.systems.map((s) => ({
+                    name: s.type,
+                    status: s.built ? ('ACTIVE' as const) : ('OFFLINE' as const),
+                    detail: s.built ? `LV ${s.level} · CAP ${s.capacity}` : undefined,
+                  }))}
+                />
+              ) : (
+                <div style={{ padding: '0.5rem 0.75rem' }}>
+                  <span style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.12em' }}>LOADING…</span>
+                </div>
+              )}
             </Panel>
 
             <Panel notch="sm">
@@ -269,11 +309,17 @@ export function MissionControl() {
                 <PanelTitle>VESSEL METRICS</PanelTitle>
               </PanelHeader>
               <PanelContent>
+                {ship ? (
+                  // Bars driven by real values: hull/reactor from system levels (level × 20, capped),
+                  // crew roster vs the display cap.
                   <div style={{ display: 'flex', flexDirection: 'column', gap: '0.875rem' }}>
-                  <Progress label="HULL INTEGRITY" value={87} />
-                  <Progress label="REACTOR OUTPUT" value={94} />
-                  <Progress label="CREW ROSTER / 6" value={50} />
+                    <Progress label="HULL INTEGRITY" value={Math.min(100, (ship.systems.find((s) => s.type === 'HULL')?.level ?? 0) * 20)} />
+                    <Progress label="REACTOR OUTPUT" value={Math.min(100, (ship.systems.find((s) => s.type === 'REACTOR')?.level ?? 0) * 20)} />
+                    <Progress label={`CREW ROSTER / ${CREW_CAPACITY}`} value={Math.round(((crewCount ?? 0) / CREW_CAPACITY) * 100)} />
                   </div>
+                ) : (
+                  <span style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.12em' }}>LOADING…</span>
+                )}
               </PanelContent>
             </Panel>
           </div>
@@ -330,132 +376,19 @@ export function MissionControl() {
                     <CrewPanel narrow={narrow} />
                   </TabsContent>
 
-                  {/* SHIP SYSTEMS TAB */}
+                  {/* SHIP SYSTEMS TAB — live data from /api/ship (state owned by MissionControl) */}
                   <TabsContent value="ship-systems" style={{ margin: 0, padding: '1rem' }}>
-                    <div
-                      style={{
-                        display: 'grid',
-                        gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)',
-                        gap: '0.75rem',
-                      }}
-                    >
-                      {shipSystemCards.map((system) => (
-                        <Card key={system.name}>
-                          <CardHeader>
-                            <div style={{ display: 'flex', alignItems: 'center' }}>
-                              <CardTitle>{system.name}</CardTitle>
-                              <Badge variant={system.status} className="ml-auto">
-                                {system.level}
-                              </Badge>
-                            </div>
-                          </CardHeader>
-                          <CardContent>
-                            <p style={{ fontSize: '0.65rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>
-                              MODULE BAY // PLACEHOLDER READOUT
-                            </p>
-                          </CardContent>
-                          <CardFooter className="gap-2">
-                            {system.actions.map((action) => (
-                              <Button key={action} variant="OUTLINE" size="SM">
-                                {action}
-                              </Button>
-                            ))}
-                          </CardFooter>
-                        </Card>
-                      ))}
-                    </div>
+                    <ShipSystemsPanel ship={ship} narrow={narrow} onChanged={setShip} researchedSlugs={researchedSlugs} />
                   </TabsContent>
 
-                  {/* SKILL TREE TAB */}
+                  {/* SKILL TREE TAB — live data from /api/tech (state owned by MissionControl) */}
                   <TabsContent value="skill-tree" style={{ margin: 0, padding: '1rem' }}>
-                    <div
-                      style={{
-                        display: 'grid',
-                        gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)',
-                        gap: '0.75rem',
-                      }}
-                    >
-                      {skillCards.map((skill) => (
-                        <Card key={skill.name}>
-                          <CardHeader>
-                            <div style={{ display: 'flex', alignItems: 'center' }}>
-                              <CardTitle>{skill.name}</CardTitle>
-                              <Badge variant={skill.state === 'AVAILABLE' ? 'ACTIVE' : 'OFFLINE'} className="ml-auto">
-                                {skill.state}
-                              </Badge>
-                            </div>
-                          </CardHeader>
-                          <CardContent>
-                            <p style={{ fontSize: '0.65rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>
-                              UNLOCKS: {skill.unlocks}
-                            </p>
-                          </CardContent>
-                          <CardFooter>
-                            <Button variant="OUTLINE" size="SM">
-                              RESEARCH
-                            </Button>
-                          </CardFooter>
-                        </Card>
-                      ))}
-                    </div>
+                    <SkillTreePanel techs={techs} ship={ship} narrow={narrow} onResearched={setTechs} />
                   </TabsContent>
 
-                  {/* MISSIONS TAB */}
+                  {/* MISSIONS TAB — live data from /api/missions */}
                   <TabsContent value="missions" style={{ margin: 0, padding: '1rem' }}>
-                    <div
-                      style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}
-                    >
-                      <Alert variant="STATUS">
-                        <AlertTitle>ENCOUNTER #E-102 — DERELICT FREIGHTER</AlertTitle>
-                        <AlertDescription>
-                          Placeholder briefing. Real encounter resolution lands with the turn engine.
-                        </AlertDescription>
-                      </Alert>
-
-                      <div
-                        style={{
-                          display: 'grid',
-                          gridTemplateColumns: narrow ? '1fr' : '1fr 1fr',
-                          gap: '0.625rem',
-                        }}
-                      >
-                        {[
-                          { label: 'DESTINATION', value: 'SECTOR 7G // DRIFT LANE' },
-                          { label: 'ETA', value: 'T-07:14 (PLACEHOLDER)' },
-                          { label: 'THREAT LEVEL', value: 'LOW — UNMANNED' },
-                          { label: 'CARGO MANIFEST', value: 'UNKNOWN' },
-                        ].map((item) => (
-                          <div
-                            key={item.label}
-                            style={{
-                              padding: '0.75rem',
-                              background: 'var(--surface)',
-                              border: '1px solid var(--border)',
-                            }}
-                          >
-                            <div
-                              style={{
-                                fontSize: '0.55rem',
-                                color: 'var(--text-muted)',
-                                letterSpacing: '0.12em',
-                                marginBottom: '0.35rem',
-                              }}
-                            >
-                              {item.label}
-                            </div>
-                            <div
-                              style={{
-                                fontSize: '0.8rem',
-                                color: 'var(--text-secondary)',
-                                letterSpacing: '0.04em',
-                              }}
-                            >
-                              {item.value}
-                            </div>
-                          </div>
-                        ))}
-                      </div>
-                    </div>
+                    <MissionPanel />
                   </TabsContent>
 
                   {/* EVENT LOG TAB */}

components/missions.tsx

@@ -0,0 +1,120 @@
+'use client'
+
+import { useCallback, useEffect, useState } from 'react'
+import { Badge } from '@/components/ui/badge'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
+import type { MissionDto } from '@/lib/game/missions'
+
+// MISSIONS tab — live data. Fetches /api/missions on mount (Radix Tabs unmounts inactive tabs, so it
+// refetches whenever the tab is opened); accept responses are applied directly (no polling). ACCEPT is
+// enabled only when the contract is AVAILABLE and no other mission is ACTIVE — mirroring what
+// POST /api/missions/{id}/accept enforces.
+
+export function MissionPanel() {
+  const [missions, setMissions] = useState<MissionDto[] | null>(null)
+  const [error, setError] = useState<string | null>(null)
+  const [busyId, setBusyId] = useState<number | null>(null) // one action at a time — turn-based game
+
+  useEffect(() => {
+    let cancelled = false
+    fetch('/api/missions')
+      .then(async (res) => {
+        if (!res.ok) throw new Error(`HTTP ${res.status}`)
+        return (await res.json()) as MissionDto[]
+      })
+      .then((m) => {
+        if (!cancelled) setMissions(m)
+      })
+      .catch((err: unknown) => {
+        if (!cancelled) setError(err instanceof Error ? err.message : String(err))
+      })
+    return () => {
+      cancelled = true
+    }
+  }, [])
+
+  const accept = useCallback(async (mission: MissionDto) => {
+    setBusyId(mission.id)
+    setError(null)
+    try {
+      const res = await fetch(`/api/missions/${mission.id}/accept`, { method: 'POST' })
+      const data = (await res.json()) as MissionDto[] & { error?: string }
+      if (!res.ok) throw new Error(data.error ?? `HTTP ${res.status}`)
+      setMissions(data) // response is the fresh board — apply directly
+    } catch (err: unknown) {
+      setError(err instanceof Error ? err.message : String(err))
+    } finally {
+      setBusyId(null)
+    }
+  }, [])
+
+  if (!missions && !error) {
+    return (
+      <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
+        <span style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.12em' }}>LOADING MISSIONS…</span>
+      </div>
+    )
+  }
+
+  const active = (missions ?? []).find((m) => m.state === 'ACTIVE')
+
+  return (
+    <div style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}>
+      {error && (
+        <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
+          <span style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>{error.toUpperCase()}</span>
+        </div>
+      )}
+      <div style={{ display: 'grid', gridTemplateColumns: 'repeat(3, 1fr)', gap: '0.75rem' }}>
+        {(missions ?? []).map((mission) => (
+          <MissionCard key={mission.id} mission={mission} busy={busyId === mission.id} blockedByActive={!!active && active.id !== mission.id} onAccept={accept} />
+        ))}
+      </div>
+    </div>
+  )
+}
+
+function MissionCard({
+  mission,
+  busy,
+  blockedByActive,
+  onAccept,
+}: {
+  mission: MissionDto
+  busy: boolean
+  blockedByActive: boolean
+  onAccept: (mission: MissionDto) => void
+}) {
+  const acceptDisabled = busy || mission.state !== 'AVAILABLE' || blockedByActive
+
+  return (
+    <Card>
+      <CardHeader>
+        <div style={{ display: 'flex', alignItems: 'center' }}>
+          <CardTitle>{mission.type}</CardTitle>
+          <Badge variant={mission.state === 'ACTIVE' ? 'ACTIVE' : mission.state === 'AVAILABLE' ? 'SCANNING' : 'OFFLINE'} className="ml-auto">
+            {mission.state}
+          </Badge>
+        </div>
+      </CardHeader>
+      <CardContent>
+        <p style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>CONTRACT // #{mission.id}</p>
+        <p style={{ fontSize: '0.65rem', color: 'var(--text-secondary)', letterSpacing: '0.08em' }}>{mission.description.toUpperCase()}</p>
+        <p style={{ fontSize: '0.62rem', color: 'var(--color-green)', letterSpacing: '0.08em' }}>
+          REWARD {mission.rewardQty}× {mission.rewardKind === 'resource' ? 'RESOURCES' : 'PARTS'}
+        </p>
+        {mission.type === 'EXPLORE' && (
+          <p style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>
+            PROGRESS // {mission.progress}/{mission.progressTarget}
+          </p>
+        )}
+      </CardContent>
+      <CardFooter>
+        <Button variant="OUTLINE" size="SM" disabled={acceptDisabled} onClick={() => onAccept(mission)}>
+          ACCEPT
+        </Button>
+      </CardFooter>
+    </Card>
+  )
+}

components/ship-systems.tsx

@@ -0,0 +1,134 @@
+'use client'
+
+import { useState } from 'react'
+import { Badge } from '@/components/ui/badge'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
+import { BUILD_PART_COST, expandCost, totalQty, upgradeCost } from '@/lib/game/ship-costs'
+import type { ShipState, ShipSystemDto } from '@/lib/game/ship'
+import { buildGate, effectiveCapacityCap, effectiveLevelCap } from '@/lib/game/tech'
+
+// SHIP SYSTEMS tab — live data. The parent (MissionControl) owns the ship state so the left
+// column mirrors actions immediately; this panel applies each action's response directly via
+// onChanged (no polling). Buttons are disabled when unaffordable, capped or gated by an
+// unresearched tech, using the same pure helpers the API enforces (lib/game/ship-costs.ts +
+// lib/game/tech.ts).
+
+interface ShipSystemsPanelProps {
+  ship: ShipState | null
+  narrow?: boolean
+  onChanged: (next: ShipState) => void
+  researchedSlugs: Set<string> // slugs of researched techs — raises caps, lifts build gates
+}
+
+export function ShipSystemsPanel({ ship, narrow, onChanged, researchedSlugs }: ShipSystemsPanelProps) {
+  const [error, setError] = useState<string | null>(null)
+  const [busy, setBusy] = useState(false) // one action at a time — turn-based game
+
+  if (!ship) {
+    return (
+      <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
+        <span style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.12em' }}>LOADING SHIP SYSTEMS…</span>
+      </div>
+    )
+  }
+
+  const resources = totalQty(ship.inventory, 'resource')
+  const parts = totalQty(ship.inventory, 'part')
+
+  async function act(url: string, body: unknown) {
+    setBusy(true)
+    setError(null)
+    try {
+      const res = await fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) })
+      const data = (await res.json()) as ShipState & { error?: string }
+      if (!res.ok) throw new Error(data.error ?? `HTTP ${res.status}`)
+      onChanged(data) // response is the fresh ship state — apply directly
+    } catch (err: unknown) {
+      setError(err instanceof Error ? err.message : String(err))
+    } finally {
+      setBusy(false)
+    }
+  }
+
+  return (
+    <div style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}>
+      {error && (
+        <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
+          <span style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>{error.toUpperCase()}</span>
+        </div>
+      )}
+      <div style={{ display: 'grid', gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)', gap: '0.75rem' }}>
+        {ship.systems.map((system) => (
+          <SystemCard key={system.id} system={system} resources={resources} parts={parts} busy={busy} researchedSlugs={researchedSlugs} onAct={act} />
+        ))}
+      </div>
+    </div>
+  )
+}
+
+function SystemCard({
+  system,
+  resources,
+  parts,
+  busy,
+  researchedSlugs,
+  onAct,
+}: {
+  system: ShipSystemDto
+  resources: number
+  parts: number
+  busy: boolean
+  researchedSlugs: Set<string>
+  onAct: (url: string, body: unknown) => void
+}) {
+  const maxLevel = effectiveLevelCap(system.type, researchedSlugs)
+  const maxCapacity = effectiveCapacityCap(system.type, researchedSlugs)
+  const gate = buildGate(system.type, researchedSlugs) // name of the required tech, or null when ungated/researched
+
+  const upgradeDisabled = busy || !system.built || system.level >= maxLevel || resources < upgradeCost(system.level)
+  const expandDisabled = busy || !system.built || system.capacity >= maxCapacity || resources < expandCost(system.capacity)
+  const buildDisabled = busy || system.built || gate !== null || parts < BUILD_PART_COST
+
+  return (
+    <Card>
+      <CardHeader>
+        <div style={{ display: 'flex', alignItems: 'center' }}>
+          <CardTitle>{system.type}</CardTitle>
+          <Badge variant={system.built ? 'ACTIVE' : 'OFFLINE'} className="ml-auto">
+            {system.built ? `LV ${system.level}` : 'OFFLINE'}
+          </Badge>
+        </div>
+      </CardHeader>
+      <CardContent>
+        <p style={{ fontSize: '0.65rem', color: 'var(--text-secondary)', letterSpacing: '0.08em' }}>
+          {system.built ? `LEVEL ${system.level} · CAPACITY ${system.capacity}` : 'NOT INSTALLED'}
+        </p>
+        <p style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>
+          {system.built
+            ? `UPGRADE ${upgradeCost(system.level)}× RES · EXPAND ${expandCost(system.capacity)}× RES`
+            : `BUILD ${BUILD_PART_COST}× PARTS`}
+        </p>
+        {!system.built && gate !== null && (
+          <p style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>REQUIRES // {gate}</p>
+        )}
+      </CardContent>
+      <CardFooter className="gap-2">
+        {system.built ? (
+          <>
+            <Button variant="OUTLINE" size="SM" disabled={upgradeDisabled} onClick={() => onAct('/api/ship/upgrade', { systemId: system.id })}>
+              UPGRADE
+            </Button>
+            <Button variant="OUTLINE" size="SM" disabled={expandDisabled} onClick={() => onAct('/api/ship/expand', { systemId: system.id })}>
+              EXPAND
+            </Button>
+          </>
+        ) : (
+          <Button variant="OUTLINE" size="SM" disabled={buildDisabled} onClick={() => onAct('/api/ship/build', { type: system.type })}>
+            BUILD NEW
+          </Button>
+        )}
+      </CardFooter>
+    </Card>
+  )
+}

components/skill-tree.tsx

@@ -0,0 +1,110 @@
+'use client'
+
+import { useState } from 'react'
+import { Badge } from '@/components/ui/badge'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
+import { totalQty } from '@/lib/game/ship-costs'
+import type { ShipState } from '@/lib/game/ship'
+import type { TechDto } from '@/lib/game/tech'
+
+// SKILL TREE tab — live data. The parent (MissionControl) owns the tech state + ship state; this panel
+// applies each research response directly via onResearched (no polling). RESEARCH is enabled only when
+// the tech is AVAILABLE and its cost is payable from the cargo hold, mirroring what POST /api/research enforces.
+
+interface SkillTreePanelProps {
+  techs: TechDto[] | null
+  ship: ShipState | null
+  narrow?: boolean
+  onResearched: (next: TechDto[]) => void
+}
+
+export function SkillTreePanel({ techs, ship, narrow, onResearched }: SkillTreePanelProps) {
+  const [error, setError] = useState<string | null>(null)
+  const [busy, setBusy] = useState(false) // one action at a time — turn-based game
+
+  if (!techs || !ship) {
+    return (
+      <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
+        <span style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.12em' }}>LOADING SKILL TREE…</span>
+      </div>
+    )
+  }
+
+  const resources = totalQty(ship.inventory, 'resource')
+  const parts = totalQty(ship.inventory, 'part')
+
+  async function research(tech: TechDto) {
+    setBusy(true)
+    setError(null)
+    try {
+      const res = await fetch('/api/research', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ techId: tech.id }) })
+      const data = (await res.json()) as TechDto[] & { error?: string }
+      if (!res.ok) throw new Error(data.error ?? `HTTP ${res.status}`)
+      onResearched(data) // response is the fresh tech tree state — apply directly
+    } catch (err: unknown) {
+      setError(err instanceof Error ? err.message : String(err))
+    } finally {
+      setBusy(false)
+    }
+  }
+
+  return (
+    <div style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}>
+      {error && (
+        <div style={{ border: '1px solid var(--border)', background: 'var(--surface)', padding: '0.75rem' }}>
+          <span style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>{error.toUpperCase()}</span>
+        </div>
+      )}
+      <div style={{ display: 'grid', gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)', gap: '0.75rem' }}>
+        {techs.map((tech) => (
+          <TechCard key={tech.slug} tech={tech} resources={resources} parts={parts} busy={busy} onResearch={research} />
+        ))}
+      </div>
+    </div>
+  )
+}
+
+function TechCard({
+  tech,
+  resources,
+  parts,
+  busy,
+  onResearch,
+}: {
+  tech: TechDto
+  resources: number
+  parts: number
+  busy: boolean
+  onResearch: (tech: TechDto) => void
+}) {
+  const affordable = tech.costKind === 'resource' ? resources >= tech.costQty : parts >= tech.costQty
+  const researchDisabled = busy || tech.state !== 'AVAILABLE' || !affordable
+
+  return (
+    <Card>
+      <CardHeader>
+        <div style={{ display: 'flex', alignItems: 'center' }}>
+          <CardTitle>{tech.name}</CardTitle>
+          <Badge variant={tech.state === 'RESEARCHED' ? 'ACTIVE' : tech.state === 'AVAILABLE' ? 'SCANNING' : 'OFFLINE'} className="ml-auto">
+            {tech.state}
+          </Badge>
+        </div>
+      </CardHeader>
+      <CardContent>
+        <p style={{ fontSize: '0.65rem', color: 'var(--text-secondary)', letterSpacing: '0.08em' }}>
+          COST {tech.costQty}× {tech.costKind === 'resource' ? 'RESOURCES' : 'PARTS'}
+        </p>
+        <p style={{ fontSize: '0.62rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>UNLOCKS // {tech.effect}</p>
+        {tech.state === 'LOCKED' && (
+          <p style={{ fontSize: '0.62rem', color: 'var(--color-red)', letterSpacing: '0.08em' }}>REQUIRES // {tech.missingPrereqs.join(' + ')}</p>
+        )}
+      </CardContent>
+      <CardFooter>
+        <Button variant="OUTLINE" size="SM" disabled={researchDisabled} onClick={() => onResearch(tech)}>
+          RESEARCH
+        </Button>
+      </CardFooter>
+    </Card>
+  )
+}

e2e/helpers.ts

@@ -0,0 +1,29 @@
+import { expect, type Page } from '@playwright/test';
+
+// Shared e2e helpers — kept out of the specs so both files can reuse them.
+
+interface WorldSystemDto { id: number; name: string; x: number; y: number; discovered: boolean; current: boolean }
+interface WorldState { systems: WorldSystemDto[]; edges: [number, number][]; turn: number }
+
+// Jump to an adjacent system, preferring one that is still undiscovered. Every jump into an
+// undiscovered system generates 4 fresh neighbours (lib/game/world.ts), so fresh territory is
+// always available — picking the FIRST edge instead ping-pongs between exhausted systems, because
+// edges come back in insertion order and the oldest route out of a system is usually the one that
+// led here. Falls back to any non-current adjacent system if none is undiscovered.
+export async function jumpToFreshSystem(page: Page): Promise<WorldState> {
+  const world = (await (await page.request.get('/api/world')).json()) as WorldState;
+  const currentId = world.systems.find((s) => s.current)!.id;
+
+  const adjacentIds = new Set<number>();
+  for (const [a, b] of world.edges) {
+    if (a === currentId) adjacentIds.add(b);
+    else if (b === currentId) adjacentIds.add(a);
+  }
+  const candidates = [...adjacentIds].map((id) => world.systems.find((s) => s.id === id)!);
+  const target = candidates.find((s) => !s.discovered) ?? candidates[0];
+  expect(target).toBeDefined(); // every system has at least one route out (ring generation)
+
+  const res = await page.request.post('/api/jump', { data: { systemId: target.id } });
+  expect(res.status()).toBe(200);
+  return (await res.json()) as WorldState;
+}

e2e/smoke.spec.ts

@@ -1,4 +1,5 @@
 import { expect, test } from '@playwright/test';
+import { jumpToFreshSystem } from './helpers';
 
 // Mirrors the /api/world + /api/system response shapes (lib/game/save.ts) — kept local so the spec stays self-contained.
 interface WorldSystemDto { id: number; name: string; x: number; y: number; discovered: boolean; current: boolean }
@@ -9,6 +10,41 @@ interface SystemState { systemId: number; systemName: string; planets: PlanetDto
 interface FoundItem { kind: string; name: string; qty: number }
 interface ExploreResult extends SystemState { outcome: FoundItem[]; crewFound: unknown }
 interface CrewDto { id: number; name: string; role: string; traitGood: string; traitBad: string; origin: string }
+interface ShipSystemDto { id: number; type: string; level: number; capacity: number; built: boolean }
+interface ShipState { systems: ShipSystemDto[]; inventory: InventoryItemDto[]; turn: number }
+interface MissionDto { id: number; type: string; description: string; targetSystemId: number | null; conditionKind: string | null; progressTarget: number; progress: number; rewardKind: string; rewardQty: number; state: string }
+
+const totalQty = (items: InventoryItemDto[], kind: string) => items.filter((i) => i.kind === kind).reduce((sum, i) => sum + i.qty, 0);
+
+// BFS over the undirected jump routes — [next, ..., target], empty when already there.
+const shortestJumpPath = (fromId: number, toId: number, edges: [number, number][]): number[] => {
+  const adj = new Map<number, number[]>();
+  for (const [a, b] of edges) {
+    if (!adj.has(a)) adj.set(a, []);
+    if (!adj.has(b)) adj.set(b, []);
+    adj.get(a)!.push(b);
+    adj.get(b)!.push(a);
+  }
+  const prev = new Map<number, number>();
+  const seen = new Set([fromId]);
+  const queue = [fromId];
+  while (queue.length > 0 && !seen.has(toId)) {
+    const cur = queue.shift()!;
+    for (const next of adj.get(cur) ?? []) {
+      if (!seen.has(next)) {
+        seen.add(next);
+        prev.set(next, cur);
+        queue.push(next);
+      }
+    }
+  }
+  expect(seen.has(toId)).toBe(true); // the world graph is connected by construction
+  const path: number[] = [];
+  for (let cur = toId; cur !== fromId; cur = prev.get(cur)!) {
+    path.unshift(cur);
+  }
+  return path;
+};
 
 test('landing page loads with the SpaceWanderer title', async ({ page }) => {
   await page.goto('/');
@@ -139,6 +175,193 @@ test('CREW tab renders real roster cards, each showing both traits and an origin
   }
 });
 
+test('SHIP SYSTEMS tab performs an affordable action and reflects it in the card and left column', async ({ page }) => {
+  // Scan bodies until something is affordable: an upgrade costs `level` resources (at least one),
+  // a build costs three parts. Jumping keeps it going if a whole system is exhausted.
+  let ship = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  const upgradeTarget = () => ship.systems.find((s) => s.built && s.level < 5 && totalQty(ship.inventory, 'resource') >= s.level);
+  // WEAPONS is gated behind the unresearched WEAPONS SYSTEMS tech — its build path is covered by
+  // the research test below, so this one only targets ungated types.
+  const buildTarget = () => (totalQty(ship.inventory, 'part') >= 3 ? ship.systems.find((s) => !s.built && s.type !== 'WEAPONS') : undefined);
+
+  let iterations = 0;
+  while (!upgradeTarget() && !buildTarget() && iterations < 60) {
+    iterations++;
+    const sys = (await (await page.request.get('/api/system')).json()) as SystemState;
+    const unexplored = sys.planets.filter((p) => !p.explored);
+    if (unexplored.length > 0) {
+      expect((await page.request.post('/api/explore', { data: { planetId: unexplored[0].id } })).status()).toBe(200);
+    } else {
+      const world = (await (await page.request.get('/api/world')).json()) as WorldState;
+      const currentId = world.systems.find((s) => s.current)!.id;
+      const edge = world.edges.find(([a, b]) => a === currentId || b === currentId)!;
+      const targetId = edge[0] === currentId ? edge[1] : edge[0];
+      expect((await page.request.post('/api/jump', { data: { systemId: targetId } })).status()).toBe(200);
+    }
+    ship = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  }
+
+  const upgrade = upgradeTarget();
+  const build = !upgrade ? buildTarget() : undefined;
+  expect(upgrade ?? build).toBeDefined(); // the bounded scan always finds something to spend on
+
+  await page.goto('/');
+  await page.getByRole('tab', { name: 'SHIP SYSTEMS' }).click();
+
+  if (upgrade) {
+    const card = page.getByRole('heading', { name: upgrade.type }).locator('xpath=ancestor::div[3]');
+    await expect(card.getByRole('button', { name: 'UPGRADE' })).toBeEnabled();
+    await card.getByRole('button', { name: 'UPGRADE' }).click();
+
+    const after = (await (await page.request.get('/api/ship')).json()) as ShipState;
+    const row = after.systems.find((s) => s.id === upgrade.id)!;
+    expect(row.level).toBe(upgrade.level + 1);
+    expect(after.turn).toBe(ship.turn + 1);
+
+    // The card badge flipped to the new level and the left column mirrors it.
+    await expect(card.getByText(`LV ${upgrade.level + 1}`)).toBeVisible();
+    await expect(page.getByText(`LV ${row.level} · CAP ${row.capacity}`)).toBeVisible();
+  } else {
+    const target = build!;
+    const card = page.getByRole('heading', { name: target.type }).locator('xpath=ancestor::div[3]');
+    await expect(card.getByRole('button', { name: 'BUILD NEW' })).toBeEnabled();
+    await card.getByRole('button', { name: 'BUILD NEW' }).click();
+
+    const after = (await (await page.request.get('/api/ship')).json()) as ShipState;
+    const row = after.systems.find((s) => s.id === target.id)!;
+    expect(row.built).toBe(true);
+    expect({ level: row.level, capacity: row.capacity }).toEqual({ level: 1, capacity: 2 });
+
+    // The card badge flipped OFFLINE → LV 1 and the left column's online count went up.
+    await expect(card.getByText('LV 1')).toBeVisible();
+    await expect(page.getByText(`${after.systems.filter((s) => s.built).length} ONLINE`)).toBeVisible();
+  }
+});
+
+test('SKILL TREE tab researches WEAPONS SYSTEMS and unlocks the gated WEAPONS build', async ({ page }) => {
+  // Research costs two parts, building WEAPONS three — scan until the hold has five. Parts drop on
+  // ~30% of scans, so P(<5 in 80 scans) is negligible; jumping keeps it going if a system exhausts.
+  let ship = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  let iterations = 0;
+  while (totalQty(ship.inventory, 'part') < 5 && iterations < 80) {
+    iterations++;
+    const sys = (await (await page.request.get('/api/system')).json()) as SystemState;
+    const unexplored = sys.planets.filter((p) => !p.explored);
+    if (unexplored.length > 0) {
+      expect((await page.request.post('/api/explore', { data: { planetId: unexplored[0].id } })).status()).toBe(200);
+    } else {
+      await jumpToFreshSystem(page); // prefer undiscovered territory — first-edge ping-pongs between exhausted systems
+    }
+    ship = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  }
+  expect(totalQty(ship.inventory, 'part')).toBeGreaterThanOrEqual(5);
+
+  await page.goto('/');
+
+  // SHIP SYSTEMS tab: BUILD NEW on WEAPONS is disabled — gated behind the unresearched tech.
+  await page.getByRole('tab', { name: 'SHIP SYSTEMS' }).click();
+  const weaponsCard = page.getByRole('heading', { name: 'WEAPONS' }).locator('xpath=ancestor::div[3]');
+  await expect(weaponsCard.getByText('REQUIRES // WEAPONS SYSTEMS')).toBeVisible();
+  await expect(weaponsCard.getByRole('button', { name: 'BUILD NEW' })).toBeDisabled();
+
+  // SKILL TREE tab: research WEAPONS SYSTEMS (two parts) — the card flips to RESEARCHED.
+  await page.getByRole('tab', { name: 'SKILL TREE' }).click();
+  const techCard = page.getByRole('heading', { name: 'WEAPONS SYSTEMS' }).locator('xpath=ancestor::div[3]');
+  await expect(techCard.getByText('AVAILABLE')).toBeVisible(); // root tech — no prerequisites
+  await expect(techCard.getByRole('button', { name: 'RESEARCH' })).toBeEnabled(); // parts ≥ 2
+  const turnBefore = ship.turn;
+  await techCard.getByRole('button', { name: 'RESEARCH' }).click();
+  await expect(techCard.getByText('RESEARCHED')).toBeVisible();
+
+  const afterResearch = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  expect(afterResearch.turn).toBe(turnBefore + 1); // research costs a turn
+
+  // The gated ship action is now available: BUILD NEW on WEAPONS flips to enabled and builds.
+  await page.getByRole('tab', { name: 'SHIP SYSTEMS' }).click();
+  await expect(weaponsCard.getByRole('button', { name: 'BUILD NEW' })).toBeEnabled();
+  await weaponsCard.getByRole('button', { name: 'BUILD NEW' }).click();
+
+  const afterBuild = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  expect(afterBuild.systems.find((s) => s.type === 'WEAPONS')!.built).toBe(true);
+  await expect(weaponsCard.getByText('LV 1')).toBeVisible();
+});
+
+test('MISSIONS tab accepts a contract and completing it grants the reward', async ({ page }) => {
+  const board = (await (await page.request.get('/api/missions')).json()) as MissionDto[];
+  expect(board.filter((m) => m.state === 'AVAILABLE').length).toBeGreaterThanOrEqual(3); // the board is always topped up
+
+  await page.goto('/');
+  await page.getByRole('tab', { name: 'MISSIONS' }).click();
+  const acceptButtons = page.getByRole('button', { name: 'ACCEPT' });
+  const panel = page.getByRole('tabpanel');
+
+  // Idempotent across retries sharing a DB: if a previous attempt already accepted a mission, it's still
+  // ACTIVE and every ACCEPT button is disabled — complete that one instead of accepting again.
+  const leftover = board.find((m) => m.state === 'ACTIVE');
+  let picked: MissionDto;
+
+  if (leftover) {
+    picked = leftover;
+    // No exact match — ACTIVE badges render a "●" dot prefix (components/ui/badge.tsx), so their text is "●ACTIVE".
+    await expect(panel.getByText('ACTIVE')).toBeVisible();
+    for (const button of await acceptButtons.all()) {
+      await expect(button).toBeDisabled();
+    }
+  } else {
+    // Prefer a scan-completable contract — fresh boards are all EXPLORE/FIND (DELIVER only appears once systems are discovered).
+    picked = board.find((m) => m.state === 'AVAILABLE' && m.type !== 'DELIVER') ?? board.find((m) => m.state === 'AVAILABLE')!;
+    const idx = board.indexOf(picked);
+
+    // One ACCEPT button per card, in board order — the picked contract's is enabled (AVAILABLE, nothing active).
+    await expect(acceptButtons.nth(idx)).toBeEnabled();
+    await acceptButtons.nth(idx).click();
+
+    // UI flipped: exactly one ACTIVE badge on the board and the accepted card's button is now disabled.
+    // No exact match — ACTIVE badges render a "●" dot prefix (components/ui/badge.tsx), so their text is "●ACTIVE".
+    await expect(panel.getByText('ACTIVE')).toBeVisible();
+    await expect(acceptButtons.nth(idx)).toBeDisabled();
+
+    // API confirms it: exactly one ACTIVE mission, the picked one (accepting cost a turn).
+    const boardAfterAccept = (await (await page.request.get('/api/missions')).json()) as MissionDto[];
+    expect(boardAfterAccept.filter((m) => m.state === 'ACTIVE')).toEqual([boardAfterAccept.find((m) => m.id === picked.id)!]);
+  }
+
+  // Baseline of the reward kind in the hold — scans during completion may add more, so assert >=.
+  const shipBefore = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  const baseline = totalQty(shipBefore.inventory, picked.rewardKind);
+
+  // Complete it. EXPLORE/FIND: scan until done, jumping when a system exhausts (parts drop on ~30% of
+  // scans, so P(a FIND-part misses in 80 scans) ≈ 0.7^80 — negligible). DELIVER: follow the shortest
+  // jump path to its target (edges only ever get added, so the precomputed path stays valid).
+  let deliverPath: number[] = [];
+  if (picked.type === 'DELIVER') {
+    const worldNow = (await (await page.request.get('/api/world')).json()) as WorldState;
+    deliverPath = shortestJumpPath(worldNow.systems.find((s) => s.current)!.id, picked.targetSystemId!, worldNow.edges);
+  }
+
+  let state = 'ACTIVE';
+  let iterations = 0;
+  while (state !== 'DONE' && iterations < 80) {
+    iterations++;
+    if (deliverPath.length > 0) {
+      expect((await page.request.post('/api/jump', { data: { systemId: deliverPath.shift()! } })).status()).toBe(200);
+    } else {
+      const sys = (await (await page.request.get('/api/system')).json()) as SystemState;
+      const unexplored = sys.planets.filter((p) => !p.explored);
+      if (unexplored.length > 0) {
+        expect((await page.request.post('/api/explore', { data: { planetId: unexplored[0].id } })).status()).toBe(200);
+      } else {
+        await jumpToFreshSystem(page); // prefer undiscovered territory — first-edge ping-pongs between exhausted systems
+      }
+    }
+    state = ((await (await page.request.get('/api/missions')).json()) as MissionDto[]).find((m) => m.id === picked.id)?.state ?? 'ACTIVE';
+  }
+  expect(state).toBe('DONE'); // the bounded loop always completes: scans are plentiful, jump paths finite
+
+  const shipAfter = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  expect(totalQty(shipAfter.inventory, picked.rewardKind)).toBeGreaterThanOrEqual(baseline + picked.rewardQty);
+});
+
 test('GET /api/version reports the app version as JSON', async ({ page }) => {
   const res = await page.request.get('/api/version');
   expect(res.status()).toBe(200);

e2e/state.spec.ts

@@ -1,6 +1,7 @@
 import { execSync } from 'node:child_process';
 import path from 'node:path';
 import { expect, test } from '@playwright/test';
+import { jumpToFreshSystem } from './helpers';
 
 // Repo root — docker-compose.yml lives here; `docker compose restart` runs on
 // this host (the test runner), browsers stay remote. CI points E2E_COMPOSE_ARGS at the
@@ -8,12 +9,14 @@ import { expect, test } from '@playwright/test';
 const repoRoot = path.join(__dirname, '..');
 const composeArgs = process.env.E2E_COMPOSE_ARGS ?? '';
 
-// Mirrors the /api/world + /api/system response shapes (lib/game/save.ts) — kept local so the spec stays self-contained.
-interface WorldSystemDto { id: number; name: string; x: number; y: number; discovered: boolean; current: boolean }
-interface WorldState { systems: WorldSystemDto[]; edges: [number, number][]; turn: number }
+// Mirrors the /api/system response shape (lib/game/save.ts) — kept local so the spec stays self-contained.
 interface PlanetDto { id: number; name: string; type: string; hazard: boolean; explored: boolean; parent: number | null }
 interface SystemState { systemId: number; systemName: string; planets: PlanetDto[]; inventory: { kind: string; name: string; qty: number }[]; turn: number }
 interface CrewDto { id: number; name: string; role: string; traitGood: string; traitBad: string; origin: string }
+interface ShipSystemDto { id: number; type: string; level: number; capacity: number; built: boolean }
+interface ShipState { systems: ShipSystemDto[]; inventory: { kind: string; name: string; qty: number }[]; turn: number }
+interface TechDto { id: number; slug: string; name: string; costKind: string; costQty: number; prereqs: string[]; effect: string; state: string; missingPrereqs: string[] }
+interface MissionDto { id: number; type: string; description: string; targetSystemId: number | null; conditionKind: string | null; progressTarget: number; progress: number; rewardKind: string; rewardQty: number; state: string }
 
 test('app survives a container restart (stack + volume persistence)', async ({ page }) => {
   test.setTimeout(180_000);
@@ -25,22 +28,13 @@ test('app survives a container restart (stack + volume persistence)', async ({ p
   expect(before.version).toMatch(/^\d+\.\d+\.\d+$/);
 
   // Game-state baseline: jump once so there is real progress that must survive the restart.
-  const worldBefore = (await (await page.request.get('/api/world')).json()) as WorldState;
-  const currentId = worldBefore.systems.find((s) => s.current)!.id;
-  const edge = worldBefore.edges.find(([a, b]) => a === currentId || b === currentId)!;
-  const targetId = edge[0] === currentId ? edge[1] : edge[0];
-  const jumpRes = await page.request.post('/api/jump', { data: { systemId: targetId } });
-  expect(jumpRes.status()).toBe(200);
+  await jumpToFreshSystem(page);
 
   // Exploration baseline: scan one body so explored state + inventory must survive too.
   // (Earlier specs may have exhausted the current system, so jump until an unscanned body shows up.)
   let sysBefore = (await (await page.request.get('/api/system')).json()) as SystemState;
   for (let i = 0; !sysBefore.planets.some((p) => !p.explored) && i < 20; i++) {
-    const world = (await (await page.request.get('/api/world')).json()) as WorldState;
-    const curId = world.systems.find((s) => s.current)!.id;
-    const e = world.edges.find(([a, b]) => a === curId || b === curId)!;
-    const tId = e[0] === curId ? e[1] : e[0];
-    expect((await page.request.post('/api/jump', { data: { systemId: tId } })).status()).toBe(200);
+    await jumpToFreshSystem(page); // prefer undiscovered territory — first-edge ping-pongs between exhausted systems
     sysBefore = (await (await page.request.get('/api/system')).json()) as SystemState;
   }
   const targetPlanet = sysBefore.planets.find((p) => !p.explored)!;
@@ -52,6 +46,19 @@ test('app survives a container restart (stack + volume persistence)', async ({ p
   const crewBefore = (await (await page.request.get('/api/crew')).json()) as CrewDto[];
   expect(crewBefore.length).toBeGreaterThanOrEqual(2); // starting crew is always seeded
 
+  // Ship baseline: the systems (levels/capacities) + cargo hold must survive too.
+  const shipBefore = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  expect(shipBefore.systems.length).toBeGreaterThan(0); // starting ship is always seeded
+
+  // Tech baseline: the researched flags must survive too.
+  const techBefore = (await (await page.request.get('/api/tech')).json()) as TechDto[];
+  expect(techBefore.length).toBeGreaterThan(0); // the tech tree is always seeded
+
+  // Mission board baseline: contracts, states and progress must survive too. The GET tops the board
+  // up first — a no-op here because every action leaves at least MIN_AVAILABLE AVAILABLE contracts.
+  const missionsBefore = (await (await page.request.get('/api/missions')).json()) as MissionDto[];
+  expect(missionsBefore.length).toBeGreaterThan(0); // the board is always seeded on new game
+
   // Restart the app container mid-run — the named DB volume must survive it.
   execSync(`docker compose ${composeArgs} restart space-wanderer`, { cwd: repoRoot, stdio: 'pipe' });
 
@@ -73,7 +80,7 @@ test('app survives a container restart (stack + volume persistence)', async ({ p
   expect(after!.version).toBe(before.version); // same build, not a re-seeded stack
 
   // Game state survived: same turn counter and current system as before the restart.
-  const worldAfter = (await (await page.request.get('/api/world')).json()) as WorldState;
+  const worldAfter = (await (await page.request.get('/api/world')).json()) as { turn: number; systems: { id: number; current: boolean }[] };
   expect(worldAfter.turn).toBe(sysExplored.turn);
   expect(worldAfter.systems.find((s) => s.current)?.id).toBe(sysExplored.systemId);
 
@@ -86,6 +93,18 @@ test('app survives a container restart (stack + volume persistence)', async ({ p
   const crewAfter = (await (await page.request.get('/api/crew')).json()) as CrewDto[];
   expect(crewAfter).toEqual(crewBefore);
 
+  // Ship state survived too: same systems, levels/capacities and cargo hold.
+  const shipAfter = (await (await page.request.get('/api/ship')).json()) as ShipState;
+  expect(shipAfter).toEqual(shipBefore);
+
+  // Tech tree survived too: same researched flags (no re-seed on restart).
+  const techAfter = (await (await page.request.get('/api/tech')).json()) as TechDto[];
+  expect(techAfter).toEqual(techBefore);
+
+  // Mission board survived too: same contracts, states and progress (no re-seed or re-top-up on restart).
+  const missionsAfter = (await (await page.request.get('/api/missions')).json()) as MissionDto[];
+  expect(missionsAfter).toEqual(missionsBefore);
+
   // The page itself serves again with the landing title.
   await page.goto('/');
   await expect(page.getByRole('heading', { name: 'SpaceWanderer' })).toBeVisible();

lib/db/client.ts

@@ -24,7 +24,8 @@ CREATE TABLE IF NOT EXISTS saves (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   seed TEXT NOT NULL,
   turn INTEGER NOT NULL DEFAULT 0,
-  created_at TEXT NOT NULL
+  created_at TEXT NOT NULL,
+  schema_version INTEGER -- which save-schema version this row was backfilled up to (NULL = v1)
 );
 
 CREATE TABLE IF NOT EXISTS solar_systems (
@@ -71,6 +72,42 @@ CREATE TABLE IF NOT EXISTS crew (
   origin TEXT NOT NULL -- 'STARTING CREW' or '<planet>, <system>' for members found while exploring
 );
 
+CREATE TABLE IF NOT EXISTS ship_systems (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  save_id INTEGER NOT NULL REFERENCES saves(id),
+  type TEXT NOT NULL,
+  level INTEGER NOT NULL DEFAULT 0, -- 0 = not built yet ('built' is derived: level > 0)
+  capacity INTEGER NOT NULL DEFAULT 0,
+  UNIQUE (save_id, type)
+);
+
+CREATE TABLE IF NOT EXISTS tech (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  save_id INTEGER NOT NULL REFERENCES saves(id),
+  slug TEXT NOT NULL, -- stable key, e.g. WEAPONS_SYSTEMS
+  name TEXT NOT NULL, -- display name, e.g. 'WEAPONS SYSTEMS'
+  cost_kind TEXT NOT NULL, -- 'resource' | 'part'
+  cost_qty INTEGER NOT NULL DEFAULT 1,
+  prerequisites TEXT NOT NULL DEFAULT '', -- comma-separated tech slugs, '' when none
+  effect TEXT NOT NULL, -- effect slug — semantics in EFFECTS (lib/game/tech.ts)
+  researched INTEGER NOT NULL DEFAULT 0,
+  UNIQUE (save_id, slug)
+);
+
+CREATE TABLE IF NOT EXISTS missions (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  save_id INTEGER NOT NULL REFERENCES saves(id),
+  type TEXT NOT NULL, -- 'DELIVER' | 'EXPLORE' | 'FIND'
+  description TEXT NOT NULL, -- human-readable objective, e.g. "Jump to Kepler Drift"
+  target_system_id INTEGER, -- DELIVER only — destination system (NULL otherwise)
+  condition_kind TEXT, -- FIND only — 'resource' | 'part' (NULL otherwise)
+  progress_target INTEGER NOT NULL DEFAULT 1, -- EXPLORE: scans required; 1 for the others
+  progress INTEGER NOT NULL DEFAULT 0, -- scans counted since acceptance; 0/1 for DELIVER/FIND
+  reward_kind TEXT NOT NULL, -- 'resource' | 'part'
+  reward_qty INTEGER NOT NULL DEFAULT 1,
+  state TEXT NOT NULL DEFAULT 'AVAILABLE' -- 'AVAILABLE' | 'ACTIVE' | 'DONE'
+);
+
 CREATE TABLE IF NOT EXISTS events (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   save_id INTEGER NOT NULL REFERENCES saves(id),
@@ -98,6 +135,14 @@ async function open(file: string): Promise<GameDb> {
   const raw = bytes ? new SQL.Database(new Uint8Array(bytes)) : new SQL.Database();
   raw.exec(DDL); // no-op for tables that already exist in an older file
 
+  // Idempotent evolution for files created by older code: CREATE TABLE IF NOT EXISTS above cannot
+  // add columns, so check and add any that are missing. This is what makes DB wipes unnecessary —
+  // old saves open fine and get backfilled by ensureSave (see lib/game/save.ts).
+  const saveCols = raw.exec('PRAGMA table_info(saves)')[0]?.values.map((v) => v[1]) ?? [];
+  if (!saveCols.includes('schema_version')) {
+    raw.exec('ALTER TABLE saves ADD COLUMN schema_version INTEGER');
+  }
+
   const instance: GameDb = { db: drizzle(raw, { schema }), raw, file };
 
   // First run: stamp when this DB was created and land the file on disk so the ./db volume

lib/db/schema.ts

@@ -1,4 +1,4 @@
-import { integer, primaryKey, real, sqliteTable, text } from 'drizzle-orm/sqlite-core'
+import { integer, primaryKey, real, sqliteTable, text, uniqueIndex } from 'drizzle-orm/sqlite-core'
 
 // Drizzle schema for game state. Single-player by design: exactly ONE save row ever exists
 // (no auth/accounts), so every table hangs off saves.id but only one save is in play.
@@ -11,6 +11,9 @@ export const saves = sqliteTable('saves', {
   seed: text('seed').notNull(),
   turn: integer('turn').notNull().default(0),
   createdAt: text('created_at').notNull(),
+  // Which schema version this save was last brought up to (NULL on saves from before the
+  // column existed = v1). ensureSave runs ordered idempotent backfill steps for anything below.
+  schemaVersion: integer('schema_version'),
 })
 
 export const solarSystems = sqliteTable('solar_systems', {
@@ -71,6 +74,58 @@ export const crew = sqliteTable('crew', {
   origin: text('origin').notNull(),
 })
 
+// The ship's systems, one row per known type (see SHIP_TYPES in lib/game/ship-costs.ts).
+// `built` is derived, not stored: level > 0 means built — unbuilt rows sit at level/capacity 0.
+export const shipSystems = sqliteTable(
+  'ship_systems',
+  {
+    id: integer('id').primaryKey({ autoIncrement: true }),
+    saveId: integer('save_id').notNull().references(() => saves.id),
+    type: text('type').notNull(),
+    level: integer('level').notNull().default(0), // 0 = not built yet
+    capacity: integer('capacity').notNull().default(0),
+  },
+  (t) => [uniqueIndex('ship_systems_save_type_unique').on(t.saveId, t.type)],
+)
+
+// The technology tree, one row per known tech (see TECHS in lib/game/tech.ts). Definitions are
+// seeded from the pure module on new game / backfill v5 — same pattern as ship_systems.
+// `researched` is the per-save progress; prerequisites/effect are stored for completeness but
+// the canonical semantics live in lib/game/tech.ts (EFFECTS).
+export const tech = sqliteTable(
+  'tech',
+  {
+    id: integer('id').primaryKey({ autoIncrement: true }),
+    saveId: integer('save_id').notNull().references(() => saves.id),
+    slug: text('slug').notNull(), // stable key, e.g. WEAPONS_SYSTEMS
+    name: text('name').notNull(), // display name, e.g. 'WEAPONS SYSTEMS'
+    costKind: text('cost_kind').notNull(), // 'resource' | 'part'
+    costQty: integer('cost_qty').notNull().default(1),
+    prerequisites: text('prerequisites').notNull().default(''), // comma-separated tech slugs, '' when none
+    effect: text('effect').notNull(), // effect slug — semantics in EFFECTS (lib/game/tech.ts)
+    researched: integer('researched', { mode: 'boolean' }).notNull().default(false),
+  },
+  (t) => [uniqueIndex('tech_save_slug_unique').on(t.saveId, t.slug)],
+)
+
+// The mission board (#10): contracts generated deterministically from the save seed, one ACTIVE
+// at a time. `type` drives completion semantics (see advanceMission in lib/game/missions.ts):
+// DELIVER jumps to target_system_id, EXPLORE counts scans up to progress_target, FIND completes
+// when a scan's haul contains condition_kind. The reward lands in inventory_items on completion.
+export const missions = sqliteTable('missions', {
+  id: integer('id').primaryKey({ autoIncrement: true }),
+  saveId: integer('save_id').notNull().references(() => saves.id),
+  type: text('type').notNull(), // 'DELIVER' | 'EXPLORE' | 'FIND'
+  description: text('description').notNull(), // human-readable objective, e.g. "Jump to Kepler Drift"
+  targetSystemId: integer('target_system_id'), // DELIVER only — destination system (NULL otherwise)
+  conditionKind: text('condition_kind'), // FIND only — 'resource' | 'part' (NULL otherwise)
+  progressTarget: integer('progress_target').notNull().default(1), // EXPLORE: scans required; 1 for the others
+  progress: integer('progress').notNull().default(0), // scans counted since acceptance; 0/1 for DELIVER/FIND
+  rewardKind: text('reward_kind').notNull(), // 'resource' | 'part'
+  rewardQty: integer('reward_qty').notNull().default(1),
+  state: text('state').notNull().default('AVAILABLE'), // 'AVAILABLE' | 'ACTIVE' | 'DONE'
+})
+
 // Append-only game log. Writers so far: new-game + jump events; later issues add more
 // writers and a read endpoint.
 export const events = sqliteTable('events', {

lib/game/missions.test.ts

@@ -0,0 +1,294 @@
+import { mkdtemp, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import { afterAll, describe, expect, it } from 'vitest'
+import { eq } from 'drizzle-orm'
+import { openGameDb, type GameDb } from '@/lib/db/client'
+import * as schema from '@/lib/db/schema'
+import { explorationRng, mulberry32, rollExploration } from './world'
+import { SCHEMA_VERSION, explorePlanet, getWorldState, jumpToSystem } from './save'
+import { acceptMission, MIN_AVAILABLE, REWARD_ITEM_NAME, generateMission, missionRng, pickMissionType, topUpMissionBoard, type MissionDef, type MissionSystem } from './missions'
+
+const dirs: string[] = []
+
+async function freshFile(): Promise<{ db: GameDb; file: string }> {
+  const dir = await mkdtemp(path.join(tmpdir(), 'sw-missions-test-'))
+  dirs.push(dir)
+  const file = path.join(dir, 'test.db')
+  return { db: await openGameDb(file), file }
+}
+
+afterAll(async () => {
+  for (const d of dirs) await rm(d, { recursive: true, force: true })
+})
+
+// A snapshot with one discovered non-current system to deliver to.
+const SYSTEMS: MissionSystem[] = [
+  { id: 1, name: 'Start', discovered: true, isCurrent: true },
+  { id: 2, name: 'Alpha', discovered: true, isCurrent: false },
+  { id: 3, name: 'Beta', discovered: false, isCurrent: false },
+]
+
+describe('generateMission (pure)', () => {
+  it('DELIVER targets a discovered non-current system and returns null when none exists', () => {
+    const def = generateMission('DELIVER', mulberry32(7), SYSTEMS)!
+    expect(def.type).toBe('DELIVER')
+    expect(def.targetSystemId).toBe(2) // the only candidate
+    expect(def.description).toContain('Alpha')
+
+    expect(generateMission('DELIVER', mulberry32(7), [SYSTEMS[0]])).toBeNull() // only the current system is discovered
+  })
+
+  it('EXPLORE targets 2–4 scans, FIND one item kind; rewards are always 1–3', () => {
+    for (let i = 0; i < 200; i++) {
+      const e = generateMission('EXPLORE', mulberry32(i), SYSTEMS)!
+      expect(e.progressTarget).toBeGreaterThanOrEqual(2)
+      expect(e.progressTarget).toBeLessThanOrEqual(4)
+      expect(e.description).toMatch(/^Scan [2-4] bodies$/)
+
+      const f = generateMission('FIND', mulberry32(i), SYSTEMS)!
+      expect(['resource', 'part']).toContain(f.conditionKind)
+      expect(f.description).toContain(f.conditionKind!)
+
+      for (const d of [e, f]) {
+        expect(d.rewardQty).toBeGreaterThanOrEqual(1)
+        expect(d.rewardQty).toBeLessThanOrEqual(3)
+      }
+    }
+  })
+
+  it('is deterministic — the same (seed, turn) stream generates identical missions', () => {
+    const a = generateMission('DELIVER', missionRng('42', 5), SYSTEMS)
+    const b = generateMission('DELIVER', missionRng('42', 5), SYSTEMS)
+    expect(a).toEqual(b)
+  })
+})
+
+describe('pickMissionType (pure)', () => {
+  it('never picks DELIVER without a target, and does pick it when one exists', () => {
+    for (let i = 0; i < 200; i++) expect(pickMissionType(mulberry32(i), false)).not.toBe('DELIVER')
+
+    const types = new Set(Array.from({ length: 200 }, (_, i) => pickMissionType(mulberry32(i), true)))
+    expect(types.has('DELIVER')).toBe(true)
+    for (const t of types) expect(['DELIVER', 'EXPLORE', 'FIND']).toContain(t)
+  })
+})
+
+describe('topUpMissionBoard', () => {
+  it('seeds a fresh game with MIN_AVAILABLE AVAILABLE non-DELIVER missions and is idempotent', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db) // new game — createNewGame already topped the board up
+
+    const rows = await db.db.select().from(schema.missions)
+    expect(rows).toHaveLength(MIN_AVAILABLE)
+    for (const r of rows) {
+      expect(r.state).toBe('AVAILABLE')
+      expect(r.type).not.toBe('DELIVER') // only the start system is discovered yet — no targets exist
+    }
+
+    await topUpMissionBoard(db) // a second pass inserts nothing
+    expect((await db.db.select().from(schema.missions)).length).toBe(MIN_AVAILABLE)
+  })
+
+  it('generates deterministically from (seed, turn) on a hand-crafted save', async () => {
+    const { db } = await freshFile()
+    // A v6 save with start (current), one discovered neighbour and one undiscovered.
+    await db.db.insert(schema.saves).values({ seed: '42', turn: 5, createdAt: new Date().toISOString(), schemaVersion: SCHEMA_VERSION })
+    const [start] = await db.db.insert(schema.solarSystems).values({ saveId: 1, name: 'Start', x: 50, y: 50, discovered: true, isCurrent: true }).returning()
+    const [alpha] = await db.db.insert(schema.solarSystems).values({ saveId: 1, name: 'Alpha', x: 60, y: 50, discovered: true, isCurrent: false }).returning()
+    const [beta] = await db.db.insert(schema.solarSystems).values({ saveId: 1, name: 'Beta', x: 40, y: 50 }).returning()
+
+    await topUpMissionBoard(db)
+
+    // Replay the same pure pipeline with the same (seed, turn) stream — must match row for row.
+    const snapshot: MissionSystem[] = [
+      { id: start.id, name: 'Start', discovered: true, isCurrent: true },
+      { id: alpha.id, name: 'Alpha', discovered: true, isCurrent: false },
+      { id: beta.id, name: 'Beta', discovered: false, isCurrent: false },
+    ]
+    const rng = missionRng('42', 5)
+    const expected: MissionDef[] = []
+    while (expected.length < MIN_AVAILABLE) {
+      const type = pickMissionType(rng, snapshot.some((s) => s.discovered && !s.isCurrent))
+      expected.push(generateMission(type, rng, snapshot)!)
+    }
+
+    const rows = await db.db.select().from(schema.missions)
+    expect(rows.map((r) => ({ type: r.type, description: r.description, targetSystemId: r.targetSystemId, conditionKind: r.conditionKind, progressTarget: r.progressTarget, rewardKind: r.rewardKind, rewardQty: r.rewardQty }))).toEqual(expected)
+  })
+})
+
+// Inserts a mission row directly so tests can control exactly what the board holds.
+async function insertMission(db: GameDb, fields: { type: string; description: string; targetSystemId?: number | null; conditionKind?: string | null; progressTarget?: number; rewardKind?: string; rewardQty?: number }): Promise<number> {
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  const [row] = await db.db.insert(schema.missions).values({ saveId: save.id, type: fields.type, description: fields.description, targetSystemId: fields.targetSystemId ?? null, conditionKind: fields.conditionKind ?? null, progressTarget: fields.progressTarget ?? 1, rewardKind: fields.rewardKind ?? 'resource', rewardQty: fields.rewardQty ?? 1 }).returning()
+  return row.id
+}
+
+describe('acceptMission', () => {
+  it('rejects unknown ids with 404 and a second accept while one is active with 409 naming the active mission', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db) // new game — board seeded
+
+    await expect(acceptMission(db, 999)).rejects.toMatchObject({ status: 404 })
+
+    const [a, b] = (await db.db.select().from(schema.missions))
+    await acceptMission(db, a.id)
+    await expect(acceptMission(db, a.id)).rejects.toMatchObject({ status: 409, message: /already active/i }) // re-accepting the active one
+    await expect(acceptMission(db, b.id)).rejects.toMatchObject({ status: 409, message: /One mission at a time/ })
+  })
+
+  it('activates an AVAILABLE contract, costs a turn, writes an event and keeps the board topped up', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db)
+    const [save] = await db.db.select().from(schema.saves).limit(1)
+    const [a] = await db.db.select().from(schema.missions)
+
+    const board = await acceptMission(db, a.id)
+
+    expect(board.find((m) => m.id === a.id)!.state).toBe('ACTIVE')
+    expect(board.filter((m) => m.state === 'AVAILABLE').length).toBeGreaterThanOrEqual(MIN_AVAILABLE) // topped back up
+    const [after] = await db.db.select().from(schema.saves).limit(1)
+    expect(after.turn).toBe(save.turn + 1)
+
+    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'mission')!
+    expect(event.message).toContain('Accepted mission')
+    expect(event.turn).toBe(save.turn + 1)
+  })
+})
+
+describe('completion', () => {
+  it('EXPLORE counts scans, completes at the target and grants the reward into the hold', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db) // new game — empty inventory, all bodies unexplored
+    const id = await insertMission(db, { type: 'EXPLORE', description: 'Scan 3 bodies', progressTarget: 3, rewardKind: 'part', rewardQty: 2 })
+
+    await acceptMission(db, id)
+    const planets = (await db.db.select().from(schema.planets)).filter((p) => p.parentId === null)
+    await explorePlanet(db, planets[0].id)
+    let mission = (await db.db.select().from(schema.missions)).find((m) => m.id === id)!
+    expect(mission.state).toBe('ACTIVE')
+    expect(mission.progress).toBe(1)
+
+    await explorePlanet(db, planets[1].id)
+    mission = (await db.db.select().from(schema.missions)).find((m) => m.id === id)!
+    expect(mission.state).toBe('ACTIVE')
+    expect(mission.progress).toBe(2)
+
+    await explorePlanet(db, planets[2].id) // third scan — completes
+    mission = (await db.db.select().from(schema.missions)).find((m) => m.id === id)!
+    expect(mission.state).toBe('DONE')
+    expect(mission.progress).toBe(3)
+
+    const reward = (await db.db.select().from(schema.inventoryItems)).find((i) => i.name === REWARD_ITEM_NAME)!
+    expect(reward.kind).toBe('part')
+    expect(reward.qty).toBe(2)
+
+    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'mission' && /complete/i.test(e.message))!
+    expect(event.message).toContain('Scan 3 bodies')
+  })
+
+  it('FIND completes when a haul contains its kind and ignores scans that do not', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db)
+    const [save] = await db.db.select().from(schema.saves).limit(1)
+    const id = await insertMission(db, { type: 'FIND', description: 'Find at least one part while scanning', conditionKind: 'part', rewardKind: 'resource', rewardQty: 3 })
+
+    // Pick bodies by their deterministic per-planet rolls — one without parts first (no progress),
+    // then one with (completes).
+    const planets = await db.db.select().from(schema.planets)
+    const haulOf = (p: { id: number }) => rollExploration(explorationRng(save.seed, p.id))
+    const noPart = planets.find((p) => !haulOf(p).some((i) => i.kind === 'part'))!
+    expect(noPart).toBeDefined()
+    const withPart = planets.find((p) => haulOf(p).some((i) => i.kind === 'part'))!
+    expect(withPart).toBeDefined()
+
+    await acceptMission(db, id)
+    await explorePlanet(db, noPart.id) // haul has no parts — the mission does not advance
+    let mission = (await db.db.select().from(schema.missions)).find((m) => m.id === id)!
+    expect(mission.state).toBe('ACTIVE')
+    expect(mission.progress).toBe(0)
+
+    await explorePlanet(db, withPart.id) // haul has parts — completes
+    mission = (await db.db.select().from(schema.missions)).find((m) => m.id === id)!
+    expect(mission.state).toBe('DONE')
+
+    const reward = (await db.db.select().from(schema.inventoryItems)).find((i) => i.name === REWARD_ITEM_NAME)!
+    expect(reward.kind).toBe('resource')
+    expect(reward.qty).toBe(3)
+  })
+
+  it('DELIVER completes on arrival at its target system', async () => {
+    const { db } = await freshFile()
+    const world = await getWorldState(db) // new game — start is current, six undiscovered neighbours
+    const [start] = await db.db.select().from(schema.solarSystems).where(eq(schema.solarSystems.isCurrent, true))
+    const neighbor = world.systems.find((s) => !s.discovered)!
+
+    await jumpToSystem(db, neighbor.id) // start is now discovered + non-current — a valid target
+    const id = await insertMission(db, { type: 'DELIVER', description: `Jump to ${start.name}`, targetSystemId: start.id, rewardKind: 'resource', rewardQty: 1 })
+
+    await acceptMission(db, id)
+
+    // Wrong destination: one of the ring neighbours generated around `neighbor` on the first jump.
+    const world2 = await getWorldState(db)
+    const wrongEdge = world2.edges.find(([a, b]) => (a === neighbor.id || b === neighbor.id) && a !== start.id && b !== start.id)!
+    const wrongId = wrongEdge[0] === neighbor.id ? wrongEdge[1] : wrongEdge[0]
+    await jumpToSystem(db, wrongId) // not the target — no completion
+    expect((await db.db.select().from(schema.missions)).find((m) => m.id === id)!.state).toBe('ACTIVE')
+
+    await jumpToSystem(db, neighbor.id) // back through `neighbor`…
+    const result = await jumpToSystem(db, start.id) // …to the target — completes
+    const mission = (await db.db.select().from(schema.missions)).find((m) => m.id === id)!
+    expect(mission.state).toBe('DONE')
+    expect(result.systems.find((s) => s.current)?.id).toBe(start.id)
+
+    const reward = (await db.db.select().from(schema.inventoryItems)).find((i) => i.name === REWARD_ITEM_NAME)!
+    expect(reward.kind).toBe('resource')
+    expect(reward.qty).toBe(1)
+  })
+
+  it('rewards of the same kind accumulate into one hold row across missions', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db)
+    const a = await insertMission(db, { type: 'EXPLORE', description: 'Scan 2 bodies', progressTarget: 2, rewardKind: 'resource', rewardQty: 2 })
+    const b = await insertMission(db, { type: 'EXPLORE', description: 'Scan 2 more bodies', progressTarget: 2, rewardKind: 'resource', rewardQty: 3 })
+    const planets = (await db.db.select().from(schema.planets)).filter((p) => p.parentId === null)
+
+    await acceptMission(db, a)
+    await explorePlanet(db, planets[0].id)
+    await explorePlanet(db, planets[1].id) // completes A — 2× resource reward
+    expect((await db.db.select().from(schema.missions)).find((m) => m.id === a)!.state).toBe('DONE')
+
+    await acceptMission(db, b)
+    await explorePlanet(db, planets[2].id)
+    await explorePlanet(db, planets[3].id) // completes B — 3× more of the same kind+name
+    expect((await db.db.select().from(schema.missions)).find((m) => m.id === b)!.state).toBe('DONE')
+
+    const rewards = (await db.db.select().from(schema.inventoryItems)).filter((i) => i.name === REWARD_ITEM_NAME)
+    expect(rewards).toHaveLength(1) // accumulated, not a second row
+    expect(rewards[0].qty).toBe(5)
+  })
+})
+
+describe('backfill v6', () => {
+  it('seeds the board on a pre-#10 save when it opens — deterministic and idempotent', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db) // new game at the current version
+
+    // Simulate a save created by pre-v6 code: no mission rows, stamped v5.
+    await db.db.delete(schema.missions)
+    await db.db.update(schema.saves).set({ schemaVersion: 5 })
+
+    await getWorldState(db) // ensureSave → backfill runs the v6 step
+
+    const rows = await db.db.select().from(schema.missions)
+    expect(rows).toHaveLength(MIN_AVAILABLE)
+    for (const r of rows) expect(r.state).toBe('AVAILABLE')
+    const [save] = await db.db.select().from(schema.saves)
+    expect(save.schemaVersion).toBe(SCHEMA_VERSION)
+
+    // Idempotent — a second pass changes nothing.
+    await getWorldState(db)
+    expect((await db.db.select().from(schema.missions)).length).toBe(MIN_AVAILABLE)
+  })
+})

lib/game/missions.ts

@@ -0,0 +1,201 @@
+import { eq } from 'drizzle-orm'
+import * as schema from '@/lib/db/schema'
+import { persist, type GameDb } from '@/lib/db/client'
+import { mulberry32, type FoundItem } from './world'
+
+// Mission board (#10): contracts generated deterministically from the save seed. Three types —
+// DELIVER (jump to a target system), EXPLORE (scan N bodies), FIND (haul in an item of one kind).
+// One mission is ACTIVE at a time; the board always holds MIN_AVAILABLE AVAILABLE contracts.
+// The pure helpers below are DB-free so generation/completion rules stay unit-testable alone.
+
+export type MissionType = 'DELIVER' | 'EXPLORE' | 'FIND'
+export type ItemKind = 'resource' | 'part'
+export type MissionStateName = 'AVAILABLE' | 'ACTIVE' | 'DONE'
+
+// The board never drops below this many AVAILABLE contracts (topped up after every action).
+export const MIN_AVAILABLE = 3
+
+// What generation produces and the DB stores — one row per mission.
+export interface MissionDef {
+  type: MissionType
+  description: string
+  targetSystemId: number | null // DELIVER only
+  conditionKind: ItemKind | null // FIND only
+  progressTarget: number // EXPLORE: scans required; 1 for the others
+  rewardKind: ItemKind
+  rewardQty: number // 1–3, consistent with exploration hauls
+}
+
+// A system as far as generation cares about.
+export interface MissionSystem {
+  id: number
+  name: string
+  discovered: boolean
+  isCurrent: boolean
+}
+
+// Deterministic per (seed, turn) — same anchoring style as world expansion in save.ts. Every
+// action costs exactly one turn, so the stream never repeats for two different top-ups.
+export function missionRng(seed: string, turn: number): () => number {
+  return mulberry32((Number(seed) + Math.imul(turn, 0x9e3779b1)) >>> 0)
+}
+
+// Which type to generate next: DELIVER when a target exists and the coin says so, else EXPLORE/FIND.
+export function pickMissionType(rng: () => number, canDeliver: boolean): MissionType {
+  if (canDeliver && rng() < 0.5) return 'DELIVER'
+  return rng() < 0.5 ? 'EXPLORE' : 'FIND'
+}
+
+// One mission of the given type from the current world snapshot. DELIVER returns null when no
+// discovered non-current system exists to target (e.g. a brand-new game).
+export function generateMission(type: MissionType, rng: () => number, systems: MissionSystem[]): MissionDef | null {
+  const rewardKind: ItemKind = rng() < 0.5 ? 'resource' : 'part'
+  const rewardQty = 1 + Math.floor(rng() * 3) // 1–3
+
+  if (type === 'DELIVER') {
+    const candidates = systems.filter((s) => s.discovered && !s.isCurrent)
+    if (candidates.length === 0) return null
+    const target = candidates[Math.floor(rng() * candidates.length)]
+    return { type, description: `Jump to ${target.name}`, targetSystemId: target.id, conditionKind: null, progressTarget: 1, rewardKind, rewardQty }
+  }
+  if (type === 'EXPLORE') {
+    const scans = 2 + Math.floor(rng() * 3) // 2–4
+    return { type, description: `Scan ${scans} bodies`, targetSystemId: null, conditionKind: null, progressTarget: scans, rewardKind, rewardQty }
+  }
+  const kind: ItemKind = rng() < 0.5 ? 'resource' : 'part'
+  return { type, description: `Find at least one ${kind} while scanning`, targetSystemId: null, conditionKind: kind, progressTarget: 1, rewardKind, rewardQty }
+}
+
+// What an action did to the world — what completion checks run against.
+export interface MissionAction {
+  jumpedTo?: number // system id reached by a jump
+  outcome?: FoundItem[] // haul from a scan
+}
+
+// How far an action advances a mission: new progress, or null when the action doesn't touch it.
+// DELIVER completes on arrival at its target; EXPLORE counts every scan (capped); FIND completes
+// when a haul contains its kind.
+export function advanceMission(
+  mission: { type: MissionType; targetSystemId: number | null; conditionKind: ItemKind | null; progressTarget: number; progress: number },
+  action: MissionAction,
+): number | null {
+  if (action.jumpedTo !== undefined) {
+    return mission.type === 'DELIVER' && mission.targetSystemId === action.jumpedTo ? 1 : null
+  }
+  if (mission.type === 'EXPLORE') return Math.min(mission.progressTarget, mission.progress + 1)
+  if (mission.type === 'FIND' && mission.conditionKind !== null && (action.outcome ?? []).some((i) => i.kind === mission.conditionKind)) return 1
+  return null
+}
+
+// --- DB layer -----------------------------------------------------------------
+
+export interface MissionDto extends MissionDef {
+  id: number
+  progress: number
+  state: MissionStateName
+}
+
+// Carries an HTTP status so route handlers can map failures to responses without re-parsing.
+export class MissionError extends Error {
+  constructor(
+    public readonly status: number,
+    message: string,
+  ) {
+    super(message)
+  }
+}
+
+async function readMissions(db: GameDb): Promise<MissionDto[]> {
+  return (await db.db.select().from(schema.missions)).map((m) => ({
+    id: m.id,
+    type: m.type as MissionType,
+    description: m.description,
+    targetSystemId: m.targetSystemId,
+    conditionKind: m.conditionKind as ItemKind | null,
+    progressTarget: m.progressTarget,
+    progress: m.progress,
+    rewardKind: m.rewardKind as ItemKind,
+    rewardQty: m.rewardQty,
+    state: m.state as MissionStateName,
+  }))
+}
+
+// The board for the MISSIONS tab. Assumes a save exists (routes call ensureSave first) and tops
+// the AVAILABLE list up before reading so the tab always has contracts to offer.
+export async function getMissions(db: GameDb): Promise<MissionDto[]> {
+  await topUpMissionBoard(db)
+  return readMissions(db)
+}
+
+// Keeps at least MIN_AVAILABLE AVAILABLE missions on the board, generating deterministically from
+// (seed, turn). Idempotent — a second call with a full list inserts nothing.
+export async function topUpMissionBoard(db: GameDb): Promise<void> {
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  if (!save) return
+  const systems = (await db.db.select().from(schema.solarSystems)).map((s) => ({ id: s.id, name: s.name, discovered: s.discovered, isCurrent: s.isCurrent }))
+
+  let available = (await db.db.select({ state: schema.missions.state }).from(schema.missions)).filter((m) => m.state === 'AVAILABLE').length
+  if (available >= MIN_AVAILABLE) return
+
+  const rng = missionRng(save.seed, save.turn)
+  while (available < MIN_AVAILABLE) {
+    const type = pickMissionType(rng, systems.some((s) => s.discovered && !s.isCurrent))
+    const def = generateMission(type, rng, systems)
+    if (!def) break // no DELIVER target — the other types always generate
+    await db.db.insert(schema.missions).values({ saveId: save.id, type: def.type, description: def.description, targetSystemId: def.targetSystemId, conditionKind: def.conditionKind, progressTarget: def.progressTarget, rewardKind: def.rewardKind, rewardQty: def.rewardQty })
+    available += 1
+  }
+}
+
+// Mission rewards are granted under one neutral name — spenders (ship actions, research) consume by kind only.
+export const REWARD_ITEM_NAME = 'MISSION REWARD'
+
+const kindLabel = (kind: ItemKind): string => (kind === 'resource' ? 'RESOURCES' : 'PARTS')
+
+// Accepts an AVAILABLE contract: it becomes THE active mission (one at a time), costs a turn like
+// every other action and writes an event. Returns the fresh board.
+export async function acceptMission(db: GameDb, missionId: number): Promise<MissionDto[]> {
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  if (!save) throw new MissionError(404, 'No save yet')
+  const rows = await readMissions(db)
+  const target = rows.find((m) => m.id === missionId)
+  if (!target) throw new MissionError(404, `Unknown mission ${missionId}`)
+  if (target.state !== 'AVAILABLE') throw new MissionError(409, `${target.description} is already ${target.state.toLowerCase()}`)
+  const active = rows.find((m) => m.state === 'ACTIVE')
+  if (active) throw new MissionError(409, `One mission at a time — finish "${active.description}" first`)
+
+  const turn = save.turn + 1
+  await db.db.update(schema.missions).set({ state: 'ACTIVE' }).where(eq(schema.missions.id, target.id))
+  await db.db.update(schema.saves).set({ turn }).where(eq(schema.saves.id, save.id))
+  await db.db.insert(schema.events).values({ saveId: save.id, turn, type: 'mission', message: `Accepted mission — ${target.description}`, createdAt: new Date().toISOString() })
+  await topUpMissionBoard(db) // one contract left the AVAILABLE list — keep the board topped up
+  await persist(db)
+
+  return readMissions(db)
+}
+
+// Runs after a jump or scan: advances the ACTIVE mission (if any) and, on completion, marks it
+// DONE, grants its reward into the cargo hold and writes an event. Called from save.ts inside the
+// action that triggered it, before persist — so everything lands in one atomic write.
+export async function checkMissionCompletion(db: GameDb, saveId: number, turn: number, action: MissionAction): Promise<void> {
+  const row = (await db.db.select().from(schema.missions)).find((m) => m.state === 'ACTIVE')
+  if (!row) return
+
+  const active = { type: row.type as MissionType, targetSystemId: row.targetSystemId, conditionKind: row.conditionKind as ItemKind | null, progressTarget: row.progressTarget, progress: row.progress }
+  const newProgress = advanceMission(active, action)
+  if (newProgress === null) return
+
+  if (newProgress >= active.progressTarget) {
+    await db.db.update(schema.missions).set({ state: 'DONE', progress: newProgress }).where(eq(schema.missions.id, row.id))
+    // The reward lands in the hold like any haul — same kind+name accumulates into one row.
+    const existing = (await db.db.select().from(schema.inventoryItems)).find((i) => i.kind === row.rewardKind && i.name === REWARD_ITEM_NAME)
+    if (existing) {
+      await db.db.update(schema.inventoryItems).set({ qty: existing.qty + row.rewardQty }).where(eq(schema.inventoryItems.id, existing.id))
+    } else {
+      await db.db.insert(schema.inventoryItems).values({ saveId, kind: row.rewardKind, name: REWARD_ITEM_NAME, qty: row.rewardQty })
+    }
+    await db.db.insert(schema.events).values({ saveId, turn, type: 'mission', message: `Mission complete — ${row.description} (+${row.rewardQty}× ${kindLabel(row.rewardKind as ItemKind)})`, createdAt: new Date().toISOString() })
+  } else {
+    await db.db.update(schema.missions).set({ progress: newProgress }).where(eq(schema.missions.id, row.id))
+  }
+}

lib/game/research.test.ts

@@ -0,0 +1,147 @@
+import { mkdtemp, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import { afterAll, describe, expect, it } from 'vitest'
+import { eq } from 'drizzle-orm'
+import { openGameDb, type GameDb } from '@/lib/db/client'
+import * as schema from '@/lib/db/schema'
+import { BUILD_PART_COST, MAX_LEVEL, upgradeCost } from './ship-costs'
+import { buildSystem, getShipState, upgradeSystem, type ShipState } from './ship'
+import { TECHS } from './tech'
+import { getTechState, researchTech } from './research'
+
+const dirs: string[] = []
+
+async function freshFile(): Promise<{ db: GameDb; file: string }> {
+  const dir = await mkdtemp(path.join(tmpdir(), 'sw-research-test-'))
+  dirs.push(dir)
+  const file = path.join(dir, 'test.db')
+  return { db: await openGameDb(file), file }
+}
+
+afterAll(async () => {
+  for (const d of dirs) await rm(d, { recursive: true, force: true })
+})
+
+async function addItem(db: GameDb, kind: 'resource' | 'part', name: string, qty: number): Promise<void> {
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  await db.db.insert(schema.inventoryItems).values({ saveId: save.id, kind, name, qty })
+}
+
+const systemOf = (state: ShipState, type: string): ShipState['systems'][number] => state.systems.find((s) => s.type === type)!
+
+describe('getTechState', () => {
+  it('new game: every tech seeded — roots AVAILABLE, chained ones LOCKED naming the missing prereq', async () => {
+    const { db } = await freshFile()
+    const techs = await getTechState(db)
+
+    expect(techs).toHaveLength(TECHS.length)
+    for (const def of TECHS) {
+      const t = techs.find((x) => x.slug === def.slug)!
+      if (def.prereqs.length === 0) {
+        expect(t.state).toBe('AVAILABLE')
+        expect(t.missingPrereqs).toEqual([])
+      } else {
+        expect(t.state).toBe('LOCKED')
+        expect(t.missingPrereqs).toEqual(def.prereqs.map((slug) => TECHS.find((x) => x.slug === slug)!.name))
+      }
+    }
+  })
+})
+
+describe('researchTech', () => {
+  it('rejects unknown id with 404, locked techs with 409 naming the missing prereq, and re-research with 409', async () => {
+    const { db } = await freshFile()
+    const techs = await getTechState(db)
+
+    await expect(researchTech(db, 999)).rejects.toMatchObject({ status: 404 })
+
+    const plasma = techs.find((t) => t.slug === 'PLASMA_CANNON')! // locked behind WEAPONS SYSTEMS
+    await expect(researchTech(db, plasma.id)).rejects.toMatchObject({ status: 409, message: /WEAPONS SYSTEMS/ })
+
+    const weapons = techs.find((t) => t.slug === 'WEAPONS_SYSTEMS')!
+    await addItem(db, 'part', 'SERVO ACTUATOR', weapons.costQty)
+    await researchTech(db, weapons.id)
+    await expect(researchTech(db, weapons.id)).rejects.toMatchObject({ status: 409 }) // already researched
+  })
+
+  it('validates the cost against the hold — 422 with no mutation when short', async () => {
+    const { db } = await freshFile()
+    const techs = await getTechState(db)
+    const nav = techs.find((t) => t.slug === 'NAV_AI')! // resource×2, root
+    const before = await getShipState(db)
+
+    await expect(researchTech(db, nav.id)).rejects.toMatchObject({ status: 422 })
+
+    expect((await getShipState(db)).turn).toBe(before.turn) // no turn spent on a failed research
+    expect((await db.db.select().from(schema.tech)).find((t) => t.slug === 'NAV_AI')!.researched).toBe(false)
+  })
+
+  it('spends the cost from the oldest row first, persists researched state, costs a turn and writes an event', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    await addItem(db, 'resource', 'IRON ORE', 1) // oldest — fully consumed by the cost of 2
+    await addItem(db, 'resource', 'CRYSTAL DUST', 5)
+
+    const techs = await getTechState(db)
+    const nav = techs.find((t) => t.slug === 'NAV_AI')!
+    const result = await researchTech(db, nav.id)
+
+    expect(result.find((t) => t.slug === 'NAV_AI')!.state).toBe('RESEARCHED')
+    expect((await db.db.select().from(schema.inventoryItems)).map((i) => [i.name, i.qty])).toEqual([['CRYSTAL DUST', 4]]) // IRON ORE row deleted
+    expect((await getShipState(db)).turn).toBe(1)
+
+    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'research')!
+    expect(event.turn).toBe(1)
+    expect(event.message).toContain('NAVIGATION AI')
+
+    // Persisted: a fresh read still shows it researched.
+    expect((await getTechState(db)).find((t) => t.slug === 'NAV_AI')!.state).toBe('RESEARCHED')
+  })
+
+  it('unlocks the next chain step once its prerequisite is researched', async () => {
+    const { db } = await freshFile()
+    await getTechState(db) // ensureSave — the save must exist before items can be added
+    await addItem(db, 'part', 'SERVO ACTUATOR', 5) // WEAPONS SYSTEMS (2) + PLASMA CANNON (3)
+    let techs = await getTechState(db)
+
+    expect(techs.find((t) => t.slug === 'PLASMA_CANNON')!.state).toBe('LOCKED')
+    await researchTech(db, techs.find((t) => t.slug === 'WEAPONS_SYSTEMS')!.id)
+
+    techs = await getTechState(db)
+    expect(techs.find((t) => t.slug === 'PLASMA_CANNON')!.state).toBe('AVAILABLE') // prereq met → researchable now
+    await researchTech(db, techs.find((t) => t.slug === 'PLASMA_CANNON')!.id)
+    expect((await getTechState(db)).find((t) => t.slug === 'PLASMA_CANNON')!.state).toBe('RESEARCHED')
+  })
+})
+
+describe('gating of ship actions', () => {
+  it('WEAPONS build is 409 until the WEAPONS SYSTEMS tech is researched, then succeeds', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    await addItem(db, 'part', 'SERVO ACTUATOR', BUILD_PART_COST + 2) // research (2) + build (3)
+
+    await expect(buildSystem(db, 'WEAPONS')).rejects.toMatchObject({ status: 409, message: /requires/ }) // gated — even with parts in the hold
+    const techs = await getTechState(db)
+    await researchTech(db, techs.find((t) => t.slug === 'WEAPONS_SYSTEMS')!.id)
+
+    const state = await buildSystem(db, 'WEAPONS')
+    expect(systemOf(state, 'WEAPONS').built).toBe(true)
+  })
+
+  it('raises the REACTOR upgrade cap once REACTOR OVERCLOCK is researched', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    const reactorId = systemOf(await getShipState(db), 'REACTOR').id
+    await db.db.update(schema.shipSystems).set({ level: MAX_LEVEL }).where(eq(schema.shipSystems.id, reactorId)) // at the base cap
+
+    await expect(upgradeSystem(db, reactorId)).rejects.toMatchObject({ status: 409 })
+
+    await addItem(db, 'resource', 'IRON ORE', 3 + upgradeCost(MAX_LEVEL)) // research cost (3) + upgrade cost at level 5
+    const techs = await getTechState(db)
+    await researchTech(db, techs.find((t) => t.slug === 'REACTOR_OVERCLOCK')!.id)
+
+    const state = await upgradeSystem(db, reactorId) // the raised cap admits one more level
+    expect(systemOf(state, 'REACTOR').level).toBe(MAX_LEVEL + 1)
+  })
+})

lib/game/research.ts

@@ -0,0 +1,79 @@
+import { eq } from 'drizzle-orm'
+import * as schema from '@/lib/db/schema'
+import { persist, type GameDb } from '@/lib/db/client'
+import { EFFECTS, TECHS, techStatus, type TechDto } from './tech'
+import { ensureSave } from './save'
+import { ShipError, spendItems } from './ship'
+
+// Technology research: the SKILL TREE tab's read + action. Researching a tech costs inventory
+// items (oldest row first, like ship actions) plus a turn, and its unlock effect then gates or
+// raises ship actions (enforced in lib/game/ship.ts via the same pure helpers).
+
+// Carries an HTTP status so route handlers can map failures to responses without re-parsing.
+export class ResearchError extends Error {
+  constructor(
+    public readonly status: number,
+    message: string,
+  ) {
+    super(message)
+  }
+}
+
+async function researchedSlugs(db: GameDb): Promise<Set<string>> {
+  return new Set((await db.db.select().from(schema.tech)).filter((t) => t.researched).map((t) => t.slug))
+}
+
+// The full tech tree with per-save state — RESEARCHED / AVAILABLE / LOCKED (with the missing
+// prerequisite names when locked). Auto-initializes like the other reads.
+export async function getTechState(db: GameDb): Promise<TechDto[]> {
+  await ensureSave(db)
+  const rows = await db.db.select().from(schema.tech)
+  const researched = new Set(rows.filter((t) => t.researched).map((t) => t.slug))
+  return TECHS.map((def) => {
+    const row = rows.find((r) => r.slug === def.slug)! // seeded on new game / backfill v5
+    const { state, missingPrereqs } = techStatus(def, researched)
+    return {
+      id: row.id,
+      slug: def.slug,
+      name: def.name,
+      costKind: def.costKind,
+      costQty: def.costQty,
+      prereqs: def.prereqs.map((slug) => TECHS.find((t) => t.slug === slug)?.name ?? slug),
+      effect: EFFECTS[def.effect]?.description ?? def.effect,
+      state,
+      missingPrereqs,
+    }
+  })
+}
+
+// Research one tech: validates prerequisites (409, naming what is missing) and the cost (422),
+// spends it from the cargo hold, marks it researched, costs a turn and writes an event.
+export async function researchTech(db: GameDb, techId: number): Promise<TechDto[]> {
+  await ensureSave(db)
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  const rows = await db.db.select().from(schema.tech)
+  const target = rows.find((t) => t.id === techId)
+  if (!target) throw new ResearchError(404, `Unknown tech ${techId}`)
+
+  const def = TECHS.find((t) => t.slug === target.slug)!
+  const researched = await researchedSlugs(db)
+  if (researched.has(def.slug)) throw new ResearchError(409, `${def.name} is already researched`)
+  const missing = def.prereqs.filter((p) => !researched.has(p)).map((slug) => TECHS.find((t) => t.slug === slug)?.name ?? slug)
+  if (missing.length > 0) throw new ResearchError(409, `${def.name} requires ${missing.join(' and ')} first`)
+
+  try {
+    await spendItems(db, save.id, def.costKind, def.costQty)
+  } catch (err) {
+    // spendItems throws ShipError(422) on a short hold — re-throw as this domain's error.
+    if (err instanceof ShipError) throw new ResearchError(err.status, err.message)
+    throw err
+  }
+
+  const turn = save.turn + 1
+  await db.db.update(schema.tech).set({ researched: true }).where(eq(schema.tech.id, target.id))
+  await db.db.update(schema.saves).set({ turn }).where(eq(schema.saves.id, save.id))
+  await db.db.insert(schema.events).values({ saveId: save.id, turn, type: 'research', message: `Researched ${def.name} (cost: ${def.costQty}× ${def.costKind === 'resource' ? 'resources' : 'parts'})`, createdAt: new Date().toISOString() })
+  await persist(db)
+
+  return getTechState(db)
+}

lib/game/save.test.ts

@@ -2,10 +2,13 @@ import { mkdtemp, rm } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import path from 'node:path'
 import { afterAll, describe, expect, it } from 'vitest'
+import { eq } from 'drizzle-orm'
 import { openGameDb, type GameDb } from '@/lib/db/client'
 import * as schema from '@/lib/db/schema'
 import { generateStartingCrew, rollCrewMember, startingCrewRng } from './crew'
-import { getCrewState, getSystemState, explorePlanet, getWorldState, jumpToSystem, type WorldState } from './save'
+import { BASE_CAPACITY, BASE_LEVEL, SHIP_TYPES } from './ship-costs'
+import { TECHS } from './tech'
+import { SCHEMA_VERSION, getCrewState, getSystemState, explorePlanet, getWorldState, jumpToSystem, type WorldState } from './save'
 import { bodyRng, explorationRng, generatePlanets, rollExploration } from './world'
 
 const dirs: string[] = []
@@ -300,3 +303,113 @@ describe('explorePlanet crew finds', () => {
     expect((await getCrewState(db)).length).toBe(before.length + 1)
   })
 })
+
+describe('backfill (old saves)', () => {
+  // Planets/moons of one system in insertion order, nested by parent — ids are excluded so a
+  // regenerated set compares equal to the original even though autoincrement moved on.
+  function bodyShape(rows: { id: number; name: string; type: string; hazard: boolean; parentId: number | null }[]) {
+    return rows
+      .filter((r) => r.parentId === null)
+      .map((p) => ({ name: p.name, type: p.type, hazard: p.hazard, moons: rows.filter((m) => m.parentId === p.id).map((m) => [m.name, m.type, m.hazard]) }))
+  }
+
+  it('upgrades a v1 save (no bodies, no crew) in place — deterministic and idempotent', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db) // new game: everything seeded at the current version
+
+    const systems = await db.db.select().from(schema.solarSystems)
+    const rowsFor = (systemId: number) => db.db.select().from(schema.planets).where(eq(schema.planets.systemId, systemId))
+    const beforeBodies: Record<number, unknown> = {}
+    for (const s of systems) {
+      const rows = await rowsFor(s.id)
+      beforeBodies[s.id] = bodyShape(rows.sort((a, b) => a.id - b.id))
+    }
+    const crewOf = (rows: { id: number; name: string; role: string; traitGood: string; traitBad: string; origin: string }[]) =>
+      rows.map((c) => ({ name: c.name, role: c.role, traitGood: c.traitGood, traitBad: c.traitBad, origin: c.origin })) // ids excluded — re-seed moves autoincrement on
+    const beforeCrew = crewOf(await db.db.select().from(schema.crew))
+    const shipOf = (rows: { id: number; type: string; level: number; capacity: number }[]) =>
+      rows.map((s) => ({ type: s.type, level: s.level, capacity: s.capacity })).sort((a, b) => a.type.localeCompare(b.type)) // ids excluded — re-seed moves autoincrement on
+    const beforeShip = shipOf(await db.db.select().from(schema.shipSystems))
+    const techShape = (rows: { id: number; slug: string; name: string; costKind: string; costQty: number; prerequisites: string; effect: string; researched: boolean }[]) =>
+      rows.map((t) => ({ slug: t.slug, name: t.name, costKind: t.costKind, costQty: t.costQty, prerequisites: t.prerequisites, effect: t.effect, researched: t.researched })).sort((a, b) => a.slug.localeCompare(b.slug))
+    const beforeTech = techShape(await db.db.select().from(schema.tech))
+
+    // Simulate a save created by pre-v0.5 code: no bodies, no crew, no ship, no tech, no version stamp (NULL).
+    await db.db.delete(schema.planets)
+    await db.db.delete(schema.crew)
+    await db.db.delete(schema.shipSystems)
+    await db.db.delete(schema.tech)
+    await db.db.update(schema.saves).set({ schemaVersion: null })
+
+    const world = await getWorldState(db) // ensureSave → backfill runs
+    expect(world.systems).toHaveLength(7)
+
+    for (const s of systems) {
+      const rows = await rowsFor(s.id)
+      expect(bodyShape(rows.sort((a, b) => a.id - b.id))).toEqual(beforeBodies[s.id]) // identical to fresh generation
+    }
+    expect(crewOf(await db.db.select().from(schema.crew))).toEqual(beforeCrew)
+    expect(shipOf(await db.db.select().from(schema.shipSystems))).toEqual(beforeShip)
+    expect(techShape(await db.db.select().from(schema.tech))).toEqual(beforeTech)
+
+    const [save] = await db.db.select().from(schema.saves)
+    expect(save.schemaVersion).toBe(SCHEMA_VERSION)
+
+    // Idempotent: a second pass changes nothing.
+    const planetCount = (await db.db.select().from(schema.planets)).length
+    await getWorldState(db)
+    expect((await db.db.select().from(schema.planets)).length).toBe(planetCount)
+    expect((await db.db.select().from(schema.crew)).length).toBe(beforeCrew.length)
+    expect(shipOf(await db.db.select().from(schema.shipSystems))).toEqual(beforeShip)
+    expect(techShape(await db.db.select().from(schema.tech))).toEqual(beforeTech)
+    for (const s of systems) {
+      const rows = await rowsFor(s.id)
+      expect(bodyShape(rows.sort((a, b) => a.id - b.id))).toEqual(beforeBodies[s.id])
+    }
+  })
+
+  it('leaves an up-to-date save untouched', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db)
+    const planetCount = (await db.db.select().from(schema.planets)).length
+    const [save] = await db.db.select().from(schema.saves)
+    expect(save.schemaVersion).toBe(SCHEMA_VERSION)
+
+    await getWorldState(db) // second read: no backfill work to do
+    expect((await db.db.select().from(schema.planets)).length).toBe(planetCount)
+  })
+
+  it('seeds the starting ship on a new game: core types built at base values, WEAPONS unbuilt', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db)
+    const rows = (await db.db.select().from(schema.shipSystems)).sort((a, b) => a.type.localeCompare(b.type))
+    expect(rows).toHaveLength(SHIP_TYPES.length)
+    for (const def of SHIP_TYPES) {
+      const row = rows.find((r) => r.type === def.type)!
+      if (def.builtAtStart) {
+        expect({ level: row.level, capacity: row.capacity }).toEqual({ level: BASE_LEVEL, capacity: BASE_CAPACITY })
+      } else {
+        expect(row.level).toBe(0) // unbuilt until a BUILD action
+        expect(row.capacity).toBe(0)
+      }
+    }
+  })
+
+  it('seeds the tech tree on a new game: one row per known tech, none researched', async () => {
+    const { db } = await freshFile()
+    await getWorldState(db)
+    const rows = (await db.db.select().from(schema.tech)).sort((a, b) => a.slug.localeCompare(b.slug))
+    expect(rows).toHaveLength(TECHS.length)
+    for (const def of TECHS) {
+      const row = rows.find((r) => r.slug === def.slug)!
+      expect({ name: row.name, costKind: row.costKind, costQty: row.costQty, prerequisites: row.prerequisites, effect: row.effect }).toEqual({
+        name: def.name,
+        costKind: def.costKind,
+        costQty: def.costQty,
+        prerequisites: def.prereqs.join(','),
+        effect: def.effect,
+      })
+      expect(row.researched).toBe(false) // nothing is researched at the start
+    }
+  })
+})

lib/game/save.ts

@@ -3,6 +3,9 @@ import type { GameDb } from '@/lib/db/client'
 import { persist } from '@/lib/db/client'
 import * as schema from '@/lib/db/schema'
 import { generateStartingCrew, rollCrewMember, startingCrewRng, type CrewMember } from './crew'
+import { BASE_CAPACITY, BASE_LEVEL, SHIP_TYPES } from './ship-costs'
+import { checkMissionCompletion, topUpMissionBoard } from './missions'
+import { TECHS } from './tech'
 import { bodyRng, explorationRng, generatePlanets, generateRing, generateStartRegion, mulberry32, rollExploration, type FoundItem } from './world'
 
 // Save lifecycle: auto-init on first hit, world state reads, and the jump action.
@@ -45,20 +48,36 @@ function expansionRng(seed: string, turn: number): () => number {
   return mulberry32((Number(seed) + turn * 1_000_003) >>> 0)
 }
 
-// Inserts one system together with its generated bodies (planets + moons), so a system is
-// never left without worlds to explore. Bodies derive from (seed, system id) via bodyRng —
-// independent of generation order and every other system.
+// The bodies of one system (planets + moons), derived from (seed, system id) via bodyRng —
+// independent of generation order and every other system. Shared by new-game creation and the
+// v2 backfill so both produce identical rows for a given save+system.
+async function insertBodiesForSystem(db: GameDb, systemId: number, seed: string): Promise<void> {
+  for (const body of generatePlanets(bodyRng(seed, systemId))) {
+    const [planet] = await db.db.insert(schema.planets).values({ systemId, parentId: null, name: body.name, type: body.type, hazard: body.hazard }).returning({ id: schema.planets.id })
+    for (const moon of body.moons) {
+      await db.db.insert(schema.planets).values({ systemId, parentId: planet.id, name: moon.name, type: moon.type, hazard: moon.hazard })
+    }
+  }
+}
+
+// Inserts one system together with its generated bodies, so a system is never left without
+// worlds to explore.
 async function insertSystemWithBodies(db: GameDb, saveId: number, ws: { name: string; x: number; y: number }, seed: string): Promise<number> {
   const [row] = await db.db.insert(schema.solarSystems).values({ saveId, name: ws.name, x: ws.x, y: ws.y }).returning({ id: schema.solarSystems.id })
-  for (const body of generatePlanets(bodyRng(seed, row.id))) {
-    const [planet] = await db.db.insert(schema.planets).values({ systemId: row.id, parentId: null, name: body.name, type: body.type, hazard: body.hazard }).returning({ id: schema.planets.id })
-    for (const moon of body.moons) {
-      await db.db.insert(schema.planets).values({ systemId: row.id, parentId: planet.id, name: moon.name, type: moon.type, hazard: moon.hazard })
-    }
-  }
+  await insertBodiesForSystem(db, row.id, seed)
   return row.id
 }
 
+// v2 backfill: every system without planets gets its generated bodies. Idempotent — systems
+// that already have rows are skipped, so a second run changes nothing.
+async function ensureBodiesForAllSystems(db: GameDb, saveId: number, seed: string): Promise<void> {
+  const systems = await db.db.select().from(schema.solarSystems)
+  for (const system of systems) {
+    const rows = await db.db.select({ id: schema.planets.id }).from(schema.planets).where(eq(schema.planets.systemId, system.id))
+    if (rows.length === 0) await insertBodiesForSystem(db, system.id, seed)
+  }
+}
+
 async function insertRoutes(db: GameDb, edges: [number, number][], resolve: (index: number) => number): Promise<void> {
   for (const [a, b] of edges) {
     const from = resolve(a)
@@ -75,17 +94,43 @@ async function seedStartingCrew(db: GameDb, saveId: number, seed: string): Promi
   }
 }
 
-// Creates the save + starting region when the DB has none. No-op otherwise — safe to call
-// on every request (single player, one process: check-then-insert cannot race in practice).
+// What each schema version added to a save. Saves created by older code lack the data newer
+// versions seed at new-game time, so ensureSave runs these steps in order for anything below
+// current — each step is idempotent (a no-op when its data already exists).
+export const SCHEMA_VERSION = 6 // v1: save + start region only · v2: bodies for every system · v3: starting crew · v4: starting ship · v5: tech tree · v6: mission board
+
+// Seeds the starting ship: one row per known type — core types built at base values, the rest
+// unbuilt (level/capacity 0) until a BUILD action.
+async function seedStartingShip(db: GameDb, saveId: number): Promise<void> {
+  for (const def of SHIP_TYPES) {
+    await db.db.insert(schema.shipSystems).values({ saveId, type: def.type, level: def.builtAtStart ? BASE_LEVEL : 0, capacity: def.builtAtStart ? BASE_CAPACITY : 0 })
+  }
+}
+
+// Seeds the tech tree: one row per known tech (definitions from lib/game/tech.ts), none researched.
+async function seedStartingTech(db: GameDb, saveId: number): Promise<void> {
+  for (const def of TECHS) {
+    await db.db.insert(schema.tech).values({ saveId, slug: def.slug, name: def.name, costKind: def.costKind, costQty: def.costQty, prerequisites: def.prereqs.join(','), effect: def.effect })
+  }
+}
+
+// Creates the save + starting region when the DB has none; backfills older saves otherwise.
+// Safe to call on every request (single player, one process: check-then-insert cannot race).
 export async function ensureSave(db: GameDb): Promise<void> {
   const existing = await db.db.select().from(schema.saves).limit(1)
-  if (existing.length > 0) return
+  if (existing.length === 0) {
+    await createNewGame(db)
+    return
+  }
+  await backfillSave(db, existing[0])
+}
 
+async function createNewGame(db: GameDb): Promise<void> {
   const seed = newSeed()
   const region = generateStartRegion(mulberry32(Number(seed)))
   const nowIso = new Date().toISOString()
 
-  const [save] = await db.db.insert(schema.saves).values({ seed, turn: 0, createdAt: nowIso }).returning()
+  const [save] = await db.db.insert(schema.saves).values({ seed, turn: 0, createdAt: nowIso, schemaVersion: SCHEMA_VERSION }).returning()
   // All inserted as undiscovered first; the start is then marked discovered + current.
   const startId = await insertSystemWithBodies(db, save.id, region.start, seed)
   const neighborIds: number[] = []
@@ -95,11 +140,46 @@ export async function ensureSave(db: GameDb): Promise<void> {
   const resolve = (index: number) => (index === 0 ? startId : neighborIds[index - 1])
   await insertRoutes(db, region.edges, resolve)
   await seedStartingCrew(db, save.id, seed)
+  await seedStartingShip(db, save.id)
+  await seedStartingTech(db, save.id)
+  await topUpMissionBoard(db) // only the start system is discovered yet — no DELIVER targets on a fresh game
 
   await db.db.insert(schema.events).values({ saveId: save.id, turn: 0, type: 'new_game', message: `New game — seed ${seed}, starting system ${region.start.name}`, createdAt: nowIso })
   await persist(db)
 }
 
+// Ordered idempotent backfill for a save created by older code. A NULL version means v1.
+async function backfillSave(db: GameDb, save: { id: number; seed: string; schemaVersion: number | null }): Promise<void> {
+  const from = save.schemaVersion ?? 1
+  let version = from
+
+  if (version < 2) {
+    await ensureBodiesForAllSystems(db, save.id, save.seed) // bodies derive from (seed, system id) — identical to fresh generation
+    version = 2
+  }
+  if (version < 3) {
+    if ((await db.db.select().from(schema.crew)).length === 0) await seedStartingCrew(db, save.id, save.seed)
+    version = 3
+  }
+  if (version < 4) {
+    if ((await db.db.select().from(schema.shipSystems)).length === 0) await seedStartingShip(db, save.id)
+    version = 4
+  }
+  if (version < 5) {
+    if ((await db.db.select().from(schema.tech)).length === 0) await seedStartingTech(db, save.id)
+    version = 5
+  }
+  if (version < 6) {
+    await topUpMissionBoard(db) // idempotent — only inserts when fewer than MIN_AVAILABLE AVAILABLE contracts exist
+    version = 6
+  }
+
+  if (from !== SCHEMA_VERSION) {
+    await db.db.update(schema.saves).set({ schemaVersion: version }).where(eq(schema.saves.id, save.id))
+    await persist(db)
+  }
+}
+
 export async function getWorldState(db: GameDb): Promise<WorldState> {
   await ensureSave(db)
   const [save] = await db.db.select().from(schema.saves).limit(1)
@@ -158,6 +238,8 @@ export async function jumpToSystem(db: GameDb, systemId: number): Promise<WorldS
 
   await db.db.update(schema.saves).set({ turn }).where(eq(schema.saves.id, save.id))
   await db.db.insert(schema.events).values({ saveId: save.id, turn, type: 'jump', message: `Jumped to ${target.name}`, createdAt: new Date().toISOString() })
+  await checkMissionCompletion(db, save.id, turn, { jumpedTo: target.id }) // an ACTIVE DELIVER may have arrived at its destination
+  await topUpMissionBoard(db)
   await persist(db)
 
   return getWorldState(db)
@@ -282,6 +364,8 @@ export async function explorePlanet(db: GameDb, planetId: number): Promise<Explo
   const crewText = crewFound ? ` — ${crewFound.name} joined the crew` : ''
   await db.db.update(schema.saves).set({ turn }).where(eq(schema.saves.id, save.id))
   await db.db.insert(schema.events).values({ saveId: save.id, turn, type: 'explore', message: `Explored ${target.name} — found ${foundText}${crewText}`, createdAt: new Date().toISOString() })
+  await checkMissionCompletion(db, save.id, turn, { outcome }) // an ACTIVE EXPLORE/FIND may have advanced or completed
+  await topUpMissionBoard(db)
   await persist(db)
 
   return { ...(await readSystemState(db)), outcome, crewFound }

lib/game/ship-costs.ts

@@ -0,0 +1,48 @@
+// Pure ship-system model: the known system types, base values and the action cost model.
+// No DB imports — both lib/game/ship.ts (server) and the frontend import from here so the
+// UI's affordability/cap logic can never drift from what the API enforces.
+
+export interface ShipTypeDef {
+  type: string
+  builtAtStart: boolean // part of the starting ship? (otherwise unbuilt until BUILD)
+}
+
+// The known system types — display order. Reuses the placeholder SHIP SYSTEMS tab card names
+// for continuity, plus HULL so the vessel-metrics hull bar can be driven by a real level.
+export const SHIP_TYPES: ShipTypeDef[] = [
+  { type: 'HULL', builtAtStart: true },
+  { type: 'REACTOR', builtAtStart: true },
+  { type: 'LIFE SUPPORT', builtAtStart: true },
+  { type: 'NAV COMPUTER', builtAtStart: true },
+  { type: 'COMMS ARRAY', builtAtStart: true },
+  { type: 'WEAPONS', builtAtStart: false },
+]
+
+export const BASE_LEVEL = 1 // what a system starts at when built (starting ship or BUILD)
+export const BASE_CAPACITY = 2
+export const MAX_LEVEL = 5 // UPGRADE cap
+export const MAX_CAPACITY = 10 // EXPAND cap
+
+// Display-only cap for the VESSEL METRICS crew roster bar (no gameplay effect yet).
+export const CREW_CAPACITY = 6
+
+// Cost model — all costs are in inventory items, consumed from the oldest cargo row of the
+// required kind first (see spendItems in lib/game/ship.ts):
+//   UPGRADE {systemId} — `level` units of any resource (scales with current level)
+//   EXPAND  {systemId} — `capacity` units of any resource (scales with current capacity)
+//   BUILD   {type}     — a flat amount of parts (parts are rarer than resources, so builds
+//                        are the bigger investment)
+export function upgradeCost(level: number): number {
+  return level
+}
+
+export function expandCost(capacity: number): number {
+  return capacity
+}
+
+export const BUILD_PART_COST = 3
+
+// Total qty of one kind across the cargo hold — used for affordability checks.
+export function totalQty(items: { kind: string; qty: number }[], kind: 'resource' | 'part'): number {
+  return items.filter((i) => i.kind === kind).reduce((sum, i) => sum + i.qty, 0)
+}

lib/game/ship.test.ts

@@ -0,0 +1,152 @@
+import { mkdtemp, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import { afterAll, describe, expect, it } from 'vitest'
+import { eq } from 'drizzle-orm'
+import { openGameDb, type GameDb } from '@/lib/db/client'
+import * as schema from '@/lib/db/schema'
+import { BASE_CAPACITY, BASE_LEVEL, BUILD_PART_COST, MAX_CAPACITY, MAX_LEVEL, SHIP_TYPES } from './ship-costs'
+import { buildSystem, expandSystem, getShipState, upgradeSystem, type ShipState } from './ship'
+
+const dirs: string[] = []
+
+async function freshFile(): Promise<{ db: GameDb; file: string }> {
+  const dir = await mkdtemp(path.join(tmpdir(), 'sw-ship-test-'))
+  dirs.push(dir)
+  const file = path.join(dir, 'test.db')
+  return { db: await openGameDb(file), file }
+}
+
+afterAll(async () => {
+  for (const d of dirs) await rm(d, { recursive: true, force: true })
+})
+
+async function addItem(db: GameDb, kind: 'resource' | 'part', name: string, qty: number): Promise<void> {
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  await db.db.insert(schema.inventoryItems).values({ saveId: save.id, kind, name, qty })
+}
+
+const systemOf = (state: ShipState, type: string): ShipState['systems'][number] => state.systems.find((s) => s.type === type)!
+
+describe('getShipState', () => {
+  it('new game: starting ship in display order — core types built at base values, WEAPONS unbuilt', async () => {
+    const { db } = await freshFile()
+    const state = await getShipState(db)
+
+    expect(state.systems.map((s) => s.type)).toEqual(SHIP_TYPES.map((t) => t.type)) // display order follows SHIP_TYPES
+    for (const def of SHIP_TYPES) {
+      const row = systemOf(state, def.type)
+      if (def.builtAtStart) {
+        expect(row.built).toBe(true)
+        expect({ level: row.level, capacity: row.capacity }).toEqual({ level: BASE_LEVEL, capacity: BASE_CAPACITY })
+      } else {
+        expect(row.built).toBe(false) // unbuilt until a BUILD action
+        expect(row.level).toBe(0)
+        expect(row.capacity).toBe(0)
+      }
+    }
+    expect(state.inventory).toEqual([])
+    expect(state.turn).toBe(0)
+  })
+})
+
+describe('upgradeSystem', () => {
+  it('rejects with 422 and mutates nothing when the hold is empty', async () => {
+    const { db } = await freshFile()
+    const before = await getShipState(db)
+    const reactorId = systemOf(before, 'REACTOR').id
+
+    await expect(upgradeSystem(db, reactorId)).rejects.toMatchObject({ status: 422 })
+
+    const after = await getShipState(db)
+    expect(systemOf(after, 'REACTOR').level).toBe(BASE_LEVEL) // no level change…
+    expect(after.turn).toBe(before.turn) // …and no turn spent on a failed action
+  })
+
+  it('rejects unknown systemId with 404 and unbuilt systems with 409', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    await expect(upgradeSystem(db, 999)).rejects.toMatchObject({ status: 404 })
+    const weaponsId = systemOf(await getShipState(db), 'WEAPONS').id
+    await expect(upgradeSystem(db, weaponsId)).rejects.toMatchObject({ status: 409 })
+  })
+
+  it('consumes the cost from the oldest resource row first (deleting rows that hit zero), costs a turn and writes an event', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    await addItem(db, 'resource', 'IRON ORE', 1) // oldest — fully consumed by the cost of 1
+    await addItem(db, 'resource', 'CRYSTAL DUST', 5)
+
+    const reactorId = systemOf(await getShipState(db), 'REACTOR').id
+    const state = await upgradeSystem(db, reactorId) // level 1 → cost 1 resource
+
+    expect(systemOf(state, 'REACTOR').level).toBe(BASE_LEVEL + 1)
+    expect((await db.db.select().from(schema.inventoryItems)).map((i) => [i.name, i.qty])).toEqual([['CRYSTAL DUST', 5]]) // IRON ORE row deleted
+    expect(state.turn).toBe(1)
+
+    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'upgrade')!
+    expect(event.turn).toBe(1)
+    expect(event.message).toContain('REACTOR')
+  })
+
+  it('caps at MAX_LEVEL with 409', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    const reactorId = systemOf(await getShipState(db), 'REACTOR').id
+    await db.db.update(schema.shipSystems).set({ level: MAX_LEVEL }).where(eq(schema.shipSystems.id, reactorId)) // cost path covered above
+
+    await expect(upgradeSystem(db, reactorId)).rejects.toMatchObject({ status: 409 })
+    expect((await getShipState(db)).turn).toBe(0)
+  })
+})
+
+describe('expandSystem', () => {
+  it('raises capacity by one for `capacity` resources; caps at MAX_CAPACITY with 409', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    await addItem(db, 'resource', 'IRON ORE', BASE_CAPACITY + 1) // cost is the current capacity (2), one left over
+
+    const hullId = systemOf(await getShipState(db), 'HULL').id
+    const state = await expandSystem(db, hullId)
+    expect(systemOf(state, 'HULL').capacity).toBe(BASE_CAPACITY + 1)
+    expect((await db.db.select().from(schema.inventoryItems)).map((i) => [i.name, i.qty])).toEqual([['IRON ORE', 1]])
+
+    await db.db.update(schema.shipSystems).set({ capacity: MAX_CAPACITY }).where(eq(schema.shipSystems.id, hullId))
+    await expect(expandSystem(db, hullId)).rejects.toMatchObject({ status: 409 })
+  })
+
+  it('rejects unknown systemId with 404 and unbuilt systems with 409', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+    await expect(expandSystem(db, 999)).rejects.toMatchObject({ status: 404 })
+    const weaponsId = systemOf(await getShipState(db), 'WEAPONS').id
+    await expect(expandSystem(db, weaponsId)).rejects.toMatchObject({ status: 409 })
+  })
+})
+
+describe('buildSystem', () => {
+  it('builds an unbuilt type at base values for a flat parts cost; a second build is 409 and unknown types are 404', async () => {
+    const { db } = await freshFile()
+    await getShipState(db)
+
+    // WEAPONS is gated behind the WEAPONS SYSTEMS tech (issue #9) — research it directly so this
+    // test keeps covering the cost path; the gate itself is covered in research.test.ts.
+    await db.db.update(schema.tech).set({ researched: true }).where(eq(schema.tech.slug, 'WEAPONS_SYSTEMS'))
+
+    await expect(buildSystem(db, 'WEAPONS')).rejects.toMatchObject({ status: 422 }) // no parts in the hold yet
+
+    await addItem(db, 'part', 'SERVO ACTUATOR', BUILD_PART_COST)
+    const state = await buildSystem(db, 'WEAPONS')
+    const weapons = systemOf(state, 'WEAPONS')
+    expect(weapons.built).toBe(true)
+    expect({ level: weapons.level, capacity: weapons.capacity }).toEqual({ level: BASE_LEVEL, capacity: BASE_CAPACITY })
+    expect(await db.db.select().from(schema.inventoryItems)).toHaveLength(0) // parts row deleted
+    expect(state.turn).toBe(1)
+
+    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'build')!
+    expect(event.message).toContain('WEAPONS')
+
+    await expect(buildSystem(db, 'WEAPONS')).rejects.toMatchObject({ status: 409 }) // already built
+    await expect(buildSystem(db, 'SHIELDS')).rejects.toMatchObject({ status: 404 }) // not a known type
+  })
+})

lib/game/ship.ts

@@ -0,0 +1,136 @@
+import { eq } from 'drizzle-orm'
+import * as schema from '@/lib/db/schema'
+import { persist, type GameDb } from '@/lib/db/client'
+import { BUILD_PART_COST, BASE_CAPACITY, BASE_LEVEL, SHIP_TYPES, expandCost, upgradeCost } from './ship-costs'
+import { buildGate, effectiveCapacityCap, effectiveLevelCap } from './tech'
+import { ensureSave, type InventoryItemDto } from './save'
+
+export interface ShipSystemDto {
+  id: number
+  type: string
+  level: number
+  capacity: number
+  built: boolean // derived — level > 0 (unbuilt rows sit at level/capacity 0)
+}
+
+// The ship's full state for the SHIP SYSTEMS tab and left column.
+export interface ShipState {
+  systems: ShipSystemDto[] // display order follows SHIP_TYPES
+  inventory: InventoryItemDto[]
+  turn: number
+}
+
+// Carries an HTTP status so route handlers can map failures to responses without re-parsing.
+export class ShipError extends Error {
+  constructor(
+    public readonly status: number,
+    message: string,
+  ) {
+    super(message)
+  }
+}
+
+async function readShipState(db: GameDb): Promise<ShipState> {
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  const rows = await db.db.select().from(schema.shipSystems)
+  const orderOf = (type: string) => {
+    const i = SHIP_TYPES.findIndex((t) => t.type === type)
+    return i === -1 ? 99 : i // unknown types (shouldn't exist) sort last
+  }
+  const systems = [...rows]
+    .sort((a, b) => orderOf(a.type) - orderOf(b.type))
+    .map((r) => ({ id: r.id, type: r.type, level: r.level, capacity: r.capacity, built: r.level > 0 }))
+  const inventory = (await db.db.select().from(schema.inventoryItems)).map((i) => ({ kind: i.kind as 'resource' | 'part', name: i.name, qty: i.qty }))
+  return { systems, inventory, turn: save.turn }
+}
+
+// The ship's systems + cargo hold + turn. Auto-initializes like the other reads.
+export async function getShipState(db: GameDb): Promise<ShipState> {
+  await ensureSave(db)
+  return readShipState(db)
+}
+
+// Consume `amount` units of one kind from the oldest cargo rows first (id order); rows that hit
+// zero are deleted. The total is checked up front, so an insufficient hold mutates nothing.
+// Exported: research.ts spends tech costs through the same path.
+export async function spendItems(db: GameDb, saveId: number, kind: 'resource' | 'part', amount: number): Promise<void> {
+  const rows = (await db.db.select().from(schema.inventoryItems)).filter((i) => i.kind === kind).sort((a, b) => a.id - b.id)
+  if (rows.reduce((sum, r) => sum + r.qty, 0) < amount) {
+    throw new ShipError(422, `Insufficient ${kind === 'resource' ? 'resources' : 'parts'} in the cargo hold — need ${amount}`)
+  }
+  let remaining = amount
+  for (const row of rows) {
+    if (remaining <= 0) break
+    const take = Math.min(row.qty, remaining)
+    remaining -= take
+    if (take >= row.qty) await db.db.delete(schema.inventoryItems).where(eq(schema.inventoryItems.id, row.id))
+    else await db.db.update(schema.inventoryItems).set({ qty: row.qty - take }).where(eq(schema.inventoryItems.id, row.id))
+  }
+}
+
+async function bumpTurnAndEvent(db: GameDb, saveId: number, turn: number, type: string, message: string): Promise<void> {
+  await db.db.update(schema.saves).set({ turn }).where(eq(schema.saves.id, saveId))
+  await db.db.insert(schema.events).values({ saveId, turn, type, message, createdAt: new Date().toISOString() })
+}
+
+// Slugs of the researched techs on this save — drives the effective caps and build gates below.
+async function researchedTechSlugs(db: GameDb): Promise<Set<string>> {
+  return new Set((await db.db.select().from(schema.tech)).filter((t) => t.researched).map((t) => t.slug))
+}
+
+// UPGRADE — level up a built system by one (capped at the effective max level, raised by techs). Cost: `level` units of any resource.
+export async function upgradeSystem(db: GameDb, systemId: number): Promise<ShipState> {
+  await ensureSave(db)
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  const target = (await db.db.select().from(schema.shipSystems)).find((s) => s.id === systemId)
+  if (!target) throw new ShipError(404, `Unknown ship system ${systemId}`)
+  if (target.level <= 0) throw new ShipError(409, `${target.type} is not built`)
+  const maxLevel = effectiveLevelCap(target.type, await researchedTechSlugs(db))
+  if (target.level >= maxLevel) throw new ShipError(409, `${target.type} is at max level (${maxLevel})`)
+
+  const cost = upgradeCost(target.level)
+  await spendItems(db, save.id, 'resource', cost)
+  const turn = save.turn + 1
+  await db.db.update(schema.shipSystems).set({ level: target.level + 1 }).where(eq(schema.shipSystems.id, target.id))
+  await bumpTurnAndEvent(db, save.id, turn, 'upgrade', `Upgraded ${target.type} to level ${target.level + 1} (cost: ${cost}× resources)`)
+  await persist(db)
+  return readShipState(db)
+}
+
+// EXPAND — raise a built system's capacity by one (capped at the effective max capacity, raised by techs). Cost: `capacity` units of any resource.
+export async function expandSystem(db: GameDb, systemId: number): Promise<ShipState> {
+  await ensureSave(db)
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  const target = (await db.db.select().from(schema.shipSystems)).find((s) => s.id === systemId)
+  if (!target) throw new ShipError(404, `Unknown ship system ${systemId}`)
+  if (target.level <= 0) throw new ShipError(409, `${target.type} is not built`)
+  const maxCapacity = effectiveCapacityCap(target.type, await researchedTechSlugs(db))
+  if (target.capacity >= maxCapacity) throw new ShipError(409, `${target.type} is at max capacity (${maxCapacity})`)
+
+  const cost = expandCost(target.capacity)
+  await spendItems(db, save.id, 'resource', cost)
+  const turn = save.turn + 1
+  await db.db.update(schema.shipSystems).set({ capacity: target.capacity + 1 }).where(eq(schema.shipSystems.id, target.id))
+  await bumpTurnAndEvent(db, save.id, turn, 'expand', `Expanded ${target.type} capacity to ${target.capacity + 1} (cost: ${cost}× resources)`)
+  await persist(db)
+  return readShipState(db)
+}
+
+// BUILD — build an unbuilt type at base values. Cost: a flat amount of parts. Some types are
+// gated behind a researched tech (see EFFECTS in lib/game/tech.ts).
+export async function buildSystem(db: GameDb, type: string): Promise<ShipState> {
+  await ensureSave(db)
+  const [save] = await db.db.select().from(schema.saves).limit(1)
+  const target = (await db.db.select().from(schema.shipSystems)).find((s) => s.type === type)
+  if (!target) throw new ShipError(404, `Unknown ship system type ${type}`)
+  if (target.level > 0) throw new ShipError(409, `${target.type} is already built`)
+  const gate = buildGate(type, await researchedTechSlugs(db))
+  if (gate) throw new ShipError(409, `Building ${type} requires the ${gate} tech`)
+
+  await spendItems(db, save.id, 'part', BUILD_PART_COST)
+  const turn = save.turn + 1
+  await db.db.update(schema.shipSystems).set({ level: BASE_LEVEL, capacity: BASE_CAPACITY }).where(eq(schema.shipSystems.id, target.id))
+  await bumpTurnAndEvent(db, save.id, turn, 'build', `Built ${target.type} at base values (cost: ${BUILD_PART_COST}× parts)`)
+  await persist(db)
+  return readShipState(db)
+}

lib/game/tech.ts

@@ -0,0 +1,102 @@
+// Pure technology model: the known techs, their costs/prerequisites and what each unlock does.
+// No DB imports — both lib/game/research.ts + lib/game/ship.ts (server) and the frontend import
+// from here so research/cap/gate logic can never drift from what the API enforces.
+
+import { MAX_CAPACITY, MAX_LEVEL } from './ship-costs'
+
+export interface TechDef {
+  slug: string // stable key used in DB + prerequisites
+  name: string // display name
+  costKind: 'resource' | 'part'
+  costQty: number
+  prereqs: string[] // slugs that must be researched first (short chains only)
+  effect: string // effect slug — see EFFECTS below
+}
+
+// The technology tree, in display order. Roots have no prerequisites; the two chains are
+// WEAPONS SYSTEMS → PLASMA CANNON and REACTOR OVERCLOCK → FUSION CORE. Costs stay small so a
+// handful of scans makes something affordable (the e2e scan loop relies on that).
+export const TECHS: TechDef[] = [
+  { slug: 'WEAPONS_SYSTEMS', name: 'WEAPONS SYSTEMS', costKind: 'part', costQty: 2, prereqs: [], effect: 'BUILD_WEAPONS' },
+  { slug: 'REACTOR_OVERCLOCK', name: 'REACTOR OVERCLOCK', costKind: 'resource', costQty: 3, prereqs: [], effect: 'REACTOR_LEVEL_CAP' },
+  { slug: 'HULL_PLATING', name: 'HULL PLATING', costKind: 'resource', costQty: 3, prereqs: [], effect: 'HULL_CAPACITY_CAP' },
+  { slug: 'NAV_AI', name: 'NAVIGATION AI', costKind: 'resource', costQty: 2, prereqs: [], effect: 'NAV_LEVEL_CAP' },
+  { slug: 'PLASMA_CANNON', name: 'PLASMA CANNON', costKind: 'part', costQty: 3, prereqs: ['WEAPONS_SYSTEMS'], effect: 'WEAPONS_LEVEL_CAP' },
+  { slug: 'FUSION_CORE', name: 'FUSION CORE', costKind: 'resource', costQty: 4, prereqs: ['REACTOR_OVERCLOCK'], effect: 'REACTOR_CAPACITY_CAP' },
+]
+
+// What each researched tech changes on the ship. `unlock_build` gates a BUILD action; the cap
+// effects raise the UPGRADE/EXPAND ceiling for one system type (stacked over the base caps).
+export interface TechEffect {
+  kind: 'unlock_build' | 'raise_level_cap' | 'raise_capacity_cap'
+  shipType: string
+  bonus?: number // cap effects only
+}
+
+export const EFFECTS: Record<string, TechEffect & { description: string }> = {
+  BUILD_WEAPONS: { kind: 'unlock_build', shipType: 'WEAPONS', description: 'Unlocks building the WEAPONS system' },
+  REACTOR_LEVEL_CAP: { kind: 'raise_level_cap', shipType: 'REACTOR', bonus: 2, description: `Raises REACTOR max level by 2 (${MAX_LEVEL} → ${MAX_LEVEL + 2})` },
+  HULL_CAPACITY_CAP: { kind: 'raise_capacity_cap', shipType: 'HULL', bonus: 3, description: `Raises HULL max capacity by 3 (${MAX_CAPACITY} → ${MAX_CAPACITY + 3})` },
+  NAV_LEVEL_CAP: { kind: 'raise_level_cap', shipType: 'NAV COMPUTER', bonus: 2, description: `Raises NAV COMPUTER max level by 2 (${MAX_LEVEL} → ${MAX_LEVEL + 2})` },
+  WEAPONS_LEVEL_CAP: { kind: 'raise_level_cap', shipType: 'WEAPONS', bonus: 2, description: `Raises WEAPONS max level by 2 (once built)` },
+  REACTOR_CAPACITY_CAP: { kind: 'raise_capacity_cap', shipType: 'REACTOR', bonus: 3, description: `Raises REACTOR max capacity by 3 (${MAX_CAPACITY} → ${MAX_CAPACITY + 3})` },
+}
+
+export type TechStateName = 'RESEARCHED' | 'AVAILABLE' | 'LOCKED'
+
+// One tech as served to the UI (GET /api/tech) and consumed by both tabs.
+export interface TechDto {
+  id: number
+  slug: string
+  name: string
+  costKind: 'resource' | 'part'
+  costQty: number
+  prereqs: string[] // prerequisite NAMES (for display), in TECHS order
+  effect: string // human-readable unlock description
+  state: TechStateName
+  missingPrereqs: string[] // unmet prerequisite names — non-empty only when LOCKED
+}
+
+export function techBySlug(slug: string): TechDef | undefined {
+  return TECHS.find((t) => t.slug === slug)
+}
+
+// RESEARCHED if done, AVAILABLE if all prerequisites are researched, LOCKED otherwise (with the
+// missing prerequisite names so the UI can say which one is blocking it).
+export function techStatus(def: TechDef, researchedSlugs: Set<string>): { state: TechStateName; missingPrereqs: string[] } {
+  if (researchedSlugs.has(def.slug)) return { state: 'RESEARCHED', missingPrereqs: [] }
+  const missing = def.prereqs.filter((p) => !researchedSlugs.has(p)).map((slug) => techBySlug(slug)?.name ?? slug)
+  return missing.length === 0 ? { state: 'AVAILABLE', missingPrereqs: [] } : { state: 'LOCKED', missingPrereqs: missing }
+}
+
+// The UPGRADE ceiling for a system type given what is researched (base cap + bonuses).
+export function effectiveLevelCap(shipType: string, researchedSlugs: Set<string>): number {
+  let cap = MAX_LEVEL
+  for (const def of TECHS) {
+    if (!researchedSlugs.has(def.slug)) continue
+    const effect = EFFECTS[def.effect]
+    if (effect?.kind === 'raise_level_cap' && effect.shipType === shipType) cap += effect.bonus ?? 0
+  }
+  return cap
+}
+
+// The EXPAND ceiling for a system type given what is researched.
+export function effectiveCapacityCap(shipType: string, researchedSlugs: Set<string>): number {
+  let cap = MAX_CAPACITY
+  for (const def of TECHS) {
+    if (!researchedSlugs.has(def.slug)) continue
+    const effect = EFFECTS[def.effect]
+    if (effect?.kind === 'raise_capacity_cap' && effect.shipType === shipType) cap += effect.bonus ?? 0
+  }
+  return cap
+}
+
+// The name of the tech that must be researched before a system type can be BUILT, or null when
+// building it is not gated (or the gate is already researched).
+export function buildGate(shipType: string, researchedSlugs: Set<string>): string | null {
+  for (const def of TECHS) {
+    const effect = EFFECTS[def.effect]
+    if (effect?.kind === 'unlock_build' && effect.shipType === shipType && !researchedSlugs.has(def.slug)) return def.name
+  }
+  return null
+}

lib/openapi.test.ts

@@ -8,12 +8,75 @@ describe('OpenAPI spec', () => {
       '/api/crew',
       '/api/explore',
       '/api/jump',
+      '/api/missions',
+      '/api/missions/{id}/accept',
+      '/api/research',
+      '/api/ship',
+      '/api/ship/build',
+      '/api/ship/expand',
+      '/api/ship/upgrade',
       '/api/system',
+      '/api/tech',
       '/api/version',
       '/api/world',
     ]);
   });
 
+  it('describes the ship endpoints as ShipState in and out, with error responses on the actions', () => {
+    const ship = openApiSpec.paths['/api/ship'].get.responses[200].content['application/json'].schema;
+    expect(ship.$ref).toBe('#/components/schemas/ShipState');
+
+    const system = openApiSpec.components.schemas.ShipSystem.properties;
+    expect(Object.keys(system)).toEqual(['id', 'type', 'level', 'capacity', 'built']);
+
+    for (const [path, request] of [
+      ['/api/ship/upgrade', '#/components/schemas/UpgradeRequest'],
+      ['/api/ship/expand', '#/components/schemas/ExpandRequest'],
+      ['/api/ship/build', '#/components/schemas/BuildRequest'],
+    ] as const) {
+      const post = openApiSpec.paths[path].post;
+      expect(post.requestBody.content['application/json'].schema.$ref).toBe(request);
+      expect(post.responses[200].content['application/json'].schema.$ref).toBe('#/components/schemas/ShipState');
+      for (const status of ['400', '404', '409', '422'] as const) {
+        expect(post.responses[status].content['application/json'].schema.$ref).toBe('#/components/schemas/Error');
+      }
+    }
+  });
+
+  it('describes the tech endpoints: GET /api/tech → Tech[], POST /api/research with error responses', () => {
+    const tech = openApiSpec.paths['/api/tech'].get.responses[200].content['application/json'].schema;
+    expect(tech.type).toBe('array');
+    expect((tech.items as { $ref: string }).$ref).toBe('#/components/schemas/Tech');
+
+    const techProps = openApiSpec.components.schemas.Tech.properties;
+    expect(Object.keys(techProps)).toEqual(['id', 'slug', 'name', 'costKind', 'costQty', 'prereqs', 'effect', 'state', 'missingPrereqs']);
+    expect((techProps.state as { enum: string[] }).enum).toEqual(['RESEARCHED', 'AVAILABLE', 'LOCKED']);
+
+    const post = openApiSpec.paths['/api/research'].post;
+    expect(post.requestBody.content['application/json'].schema.$ref).toBe('#/components/schemas/ResearchRequest');
+    expect(post.responses[200].content['application/json'].schema.items.$ref).toBe('#/components/schemas/Tech');
+    for (const status of ['400', '404', '409', '422'] as const) {
+      expect(post.responses[status].content['application/json'].schema.$ref).toBe('#/components/schemas/Error');
+    }
+  });
+
+  it('describes the mission endpoints: GET /api/missions → Mission[], POST accept with error responses', () => {
+    const missions = openApiSpec.paths['/api/missions'].get.responses[200].content['application/json'].schema;
+    expect(missions.type).toBe('array');
+    expect((missions.items as { $ref: string }).$ref).toBe('#/components/schemas/Mission');
+
+    const props = openApiSpec.components.schemas.Mission.properties;
+    expect(Object.keys(props)).toEqual(['id', 'type', 'description', 'targetSystemId', 'conditionKind', 'progressTarget', 'progress', 'rewardKind', 'rewardQty', 'state']);
+    expect((props.type as { enum: string[] }).enum).toEqual(['DELIVER', 'EXPLORE', 'FIND']);
+    expect((props.state as { enum: string[] }).enum).toEqual(['AVAILABLE', 'ACTIVE', 'DONE']);
+
+    const post = openApiSpec.paths['/api/missions/{id}/accept'].post;
+    expect(post.responses[200].content['application/json'].schema.items.$ref).toBe('#/components/schemas/Mission');
+    for (const status of ['400', '404', '409'] as const) {
+      expect(post.responses[status].content['application/json'].schema.$ref).toBe('#/components/schemas/Error');
+    }
+  });
+
   it('describes /api/crew as an array of CrewMember and crewFound on ExploreResult', () => {
     const crew = openApiSpec.paths['/api/crew'].get.responses[200].content['application/json'].schema;
     expect(crew.type).toBe('array');

lib/openapi.ts

@@ -186,6 +186,343 @@ export const openApiSpec = {
         },
       },
     },
+    '/api/ship': {
+      get: {
+        summary: 'Ship state',
+        description:
+          "The ship's systems (built flag derived from level), the cargo hold and the turn counter. The starting ship is seeded on new game — core types built at base values, the rest unbuilt until a build action. Auto-initializes a new game when no save exists yet.",
+        operationId: 'getShip',
+        responses: {
+          200: {
+            description: 'Current ship state',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/ShipState' },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/ship/upgrade': {
+      post: {
+        summary: 'Upgrade a ship system',
+        description:
+          "Level up a built ship system by one (capped at max level). Costs `level` units of any resource, consumed from the oldest cargo row first, plus a turn. Returns the fresh ship state.",
+        operationId: 'upgradeShipSystem',
+        requestBody: {
+          required: true,
+          content: {
+            'application/json': {
+              schema: { $ref: '#/components/schemas/UpgradeRequest' },
+            },
+          },
+        },
+        responses: {
+          200: {
+            description: 'Fresh ship state after the upgrade',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/ShipState' },
+              },
+            },
+          },
+          400: {
+            description: 'Malformed body or non-integer systemId',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          404: {
+            description: 'Unknown ship system id',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          409: {
+            description: 'System is not built or already at max level',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          422: {
+            description: 'Not enough resources in the cargo hold for the cost',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/ship/expand': {
+      post: {
+        summary: 'Expand a ship system',
+        description:
+          "Raise a built ship system's capacity by one (capped at max capacity). Costs `capacity` units of any resource, consumed from the oldest cargo row first, plus a turn. Returns the fresh ship state.",
+        operationId: 'expandShipSystem',
+        requestBody: {
+          required: true,
+          content: {
+            'application/json': {
+              schema: { $ref: '#/components/schemas/ExpandRequest' },
+            },
+          },
+        },
+        responses: {
+          200: {
+            description: 'Fresh ship state after the expansion',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/ShipState' },
+              },
+            },
+          },
+          400: {
+            description: 'Malformed body or non-integer systemId',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          404: {
+            description: 'Unknown ship system id',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          409: {
+            description: 'System is not built or already at max capacity',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          422: {
+            description: 'Not enough resources in the cargo hold for the cost',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/ship/build': {
+      post: {
+        summary: 'Build a ship system',
+        description:
+          'Build an unbuilt ship system type at base values. Costs a flat amount of parts, consumed from the oldest cargo row first, plus a turn. Returns the fresh ship state.',
+        operationId: 'buildShipSystem',
+        requestBody: {
+          required: true,
+          content: {
+            'application/json': {
+              schema: { $ref: '#/components/schemas/BuildRequest' },
+            },
+          },
+        },
+        responses: {
+          200: {
+            description: 'Fresh ship state after the build',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/ShipState' },
+              },
+            },
+          },
+          400: {
+            description: 'Malformed body or empty type',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          404: {
+            description: 'Unknown ship system type',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          409: {
+            description: 'System is already built',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          422: {
+            description: 'Not enough parts in the cargo hold for the cost',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/tech': {
+      get: {
+        summary: 'Tech tree state',
+        description:
+          "The full technology tree with per-save state — RESEARCHED if done, AVAILABLE if all prerequisites are researched, LOCKED otherwise (with the missing prerequisite names). Researching a tech gates or raises ship actions (e.g. building WEAPONS requires the WEAPONS SYSTEMS tech). Auto-initializes a new game when no save exists yet.",
+        operationId: 'getTech',
+        responses: {
+          200: {
+            description: 'The tech tree with per-save state',
+            content: {
+              'application/json': {
+                schema: { type: 'array', items: { $ref: '#/components/schemas/Tech' } },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/research': {
+      post: {
+        summary: 'Research a tech',
+        description:
+          "Validates the prerequisites (409, naming what is missing) and the cost against the cargo hold (422), spends the cost from the oldest row first, marks the tech researched, increments the turn counter and writes a research event. Returns the fresh tech tree state.",
+        operationId: 'researchTech',
+        requestBody: {
+          required: true,
+          content: {
+            'application/json': {
+              schema: { $ref: '#/components/schemas/ResearchRequest' },
+            },
+          },
+        },
+        responses: {
+          200: {
+            description: 'Fresh tech tree state after the research',
+            content: {
+              'application/json': {
+                schema: { type: 'array', items: { $ref: '#/components/schemas/Tech' } },
+              },
+            },
+          },
+          400: {
+            description: 'Malformed body or non-integer techId',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          404: {
+            description: 'Unknown tech id',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          409: {
+            description: 'Tech is already researched or a prerequisite is not researched yet (message names the missing prereq)',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          422: {
+            description: 'Not enough of the required kind in the cargo hold for the cost',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/missions': {
+      get: {
+        summary: 'Mission board',
+        description:
+          "The save's mission contracts — generated deterministically from the seed, always topped up to at least three AVAILABLE. One mission is ACTIVE at a time; completion is checked after jumps and scans (DELIVER on arrival at its target system, EXPLORE after N scans, FIND when a haul contains its kind) and grants the reward into the cargo hold. Auto-initializes a new game when no save exists yet.",
+        operationId: 'getMissions',
+        responses: {
+          200: {
+            description: 'The mission board',
+            content: {
+              'application/json': {
+                schema: { type: 'array', items: { $ref: '#/components/schemas/Mission' } },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/api/missions/{id}/accept': {
+      post: {
+        summary: 'Accept a mission',
+        description:
+          "Makes an AVAILABLE contract the single ACTIVE one (409 while another is active, or when it isn't AVAILABLE). Costs a turn and writes a mission event. Returns the fresh board.",
+        operationId: 'acceptMission',
+        parameters: [
+          {
+            name: 'id',
+            in: 'path',
+            required: true,
+            schema: { type: 'integer' },
+            description: 'missions.id of the contract to accept',
+          },
+        ],
+        responses: {
+          200: {
+            description: 'Fresh mission board after the acceptance',
+            content: {
+              'application/json': {
+                schema: { type: 'array', items: { $ref: '#/components/schemas/Mission' } },
+              },
+            },
+          },
+          400: {
+            description: 'Non-integer id in the path',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          404: {
+            description: 'Unknown mission id',
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+          409: {
+            description: "Mission isn't AVAILABLE, or another mission is already ACTIVE (one at a time)",
+            content: {
+              'application/json': {
+                schema: { $ref: '#/components/schemas/Error' },
+              },
+            },
+          },
+        },
+      },
+    },
   },
   components: {
     schemas: {
@@ -275,6 +612,97 @@ export const openApiSpec = {
         },
         required: ['id', 'name', 'role', 'trait_good', 'trait_bad', 'origin'],
       },
+      ShipSystem: {
+        type: 'object',
+        properties: {
+          id: { type: 'integer' },
+          type: { type: 'string', description: "System type, e.g. REACTOR or WEAPONS" },
+          level: { type: 'integer', description: '0 when not built yet' },
+          capacity: { type: 'integer', description: '0 when not built yet' },
+          built: { type: 'boolean', description: 'Derived — true when level > 0' },
+        },
+        required: ['id', 'type', 'level', 'capacity', 'built'],
+      },
+      ShipState: {
+        type: 'object',
+        properties: {
+          systems: {
+            type: 'array',
+            description: "The ship's systems in display order",
+            items: { $ref: '#/components/schemas/ShipSystem' },
+          },
+          inventory: { type: 'array', items: { $ref: '#/components/schemas/InventoryItem' } },
+          turn: { type: 'integer', description: 'Turn counter — one per jump, exploration or ship action' },
+        },
+        required: ['systems', 'inventory', 'turn'],
+      },
+      Tech: {
+        type: 'object',
+        properties: {
+          id: { type: 'integer' },
+          slug: { type: 'string', description: "Stable key, e.g. WEAPONS_SYSTEMS" },
+          name: { type: 'string', description: "Display name, e.g. 'WEAPONS SYSTEMS'" },
+          costKind: { type: 'string', enum: ['resource', 'part'] },
+          costQty: { type: 'integer' },
+          prereqs: {
+            type: 'array',
+            description: 'Prerequisite tech names (empty for roots)',
+            items: { type: 'string' },
+          },
+          effect: { type: 'string', description: "Human-readable unlock, e.g. 'Unlocks building the WEAPONS system'" },
+          state: { type: 'string', enum: ['RESEARCHED', 'AVAILABLE', 'LOCKED'] },
+          missingPrereqs: {
+            type: 'array',
+            description: 'Unmet prerequisite names — non-empty only when LOCKED',
+            items: { type: 'string' },
+          },
+        },
+        required: ['id', 'slug', 'name', 'costKind', 'costQty', 'prereqs', 'effect', 'state', 'missingPrereqs'],
+      },
+      ResearchRequest: {
+        type: 'object',
+        properties: {
+          techId: { type: 'integer', description: 'tech.id of the tech to research' },
+        },
+        required: ['techId'],
+      },
+      Mission: {
+        type: 'object',
+        properties: {
+          id: { type: 'integer' },
+          type: { type: 'string', enum: ['DELIVER', 'EXPLORE', 'FIND'] },
+          description: { type: 'string', description: "Human-readable objective, e.g. 'Jump to Kepler Drift'" },
+          targetSystemId: { type: ['integer', 'null'], nullable: true, description: 'DELIVER only — destination system (NULL otherwise)' },
+          conditionKind: { type: ['string', 'null'], enum: ['resource', 'part', null], description: 'FIND only — item kind to haul in (NULL otherwise)' },
+          progressTarget: { type: 'integer', description: 'EXPLORE: scans required; 1 for the others' },
+          progress: { type: 'integer', description: 'Scans counted since acceptance; 0/1 for DELIVER/FIND' },
+          rewardKind: { type: 'string', enum: ['resource', 'part'] },
+          rewardQty: { type: 'integer', description: 'Reward quantity (1–3), granted into the cargo hold on completion' },
+          state: { type: 'string', enum: ['AVAILABLE', 'ACTIVE', 'DONE'] },
+        },
+        required: ['id', 'type', 'description', 'targetSystemId', 'conditionKind', 'progressTarget', 'progress', 'rewardKind', 'rewardQty', 'state'],
+      },
+      UpgradeRequest: {
+        type: 'object',
+        properties: {
+          systemId: { type: 'integer', description: 'ship_systems.id of the built system to level up' },
+        },
+        required: ['systemId'],
+      },
+      ExpandRequest: {
+        type: 'object',
+        properties: {
+          systemId: { type: 'integer', description: 'ship_systems.id of the built system to expand' },
+        },
+        required: ['systemId'],
+      },
+      BuildRequest: {
+        type: 'object',
+        properties: {
+          type: { type: 'string', description: "Ship system type to build, e.g. WEAPONS (see ShipSystem.type)" },
+        },
+        required: ['type'],
+      },
       SystemState: {
         type: 'object',
         properties: {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "space-wanderer",
-  "version": "0.5.0",
+  "version": "0.8.0",
   "private": true,
   "scripts": {
     "dev": "next dev -p 3000",