test: e2e jump helper prefers undiscovered systems — fixes exhausted-territory ping-pong

CHANGELOG.md

@@ -1,5 +1,34 @@
 # Changelog
 
+## 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.
+- Pure seeded crew generation (`lib/game/crew.ts`, same pattern as world.ts): name pools (16 first × 22 last, unique per roster), role pool of 8, good/bad trait pools of 10 each. `generateStartingCrew` gives a new game 2–3 members with unique names and roles; `rollCrewMember` finds a joining member on ~18% of scans (`CREW_CHANCE = 0.18`).
+- Starting crew is seeded in `ensureSave` from the save seed via `startingCrewRng(seed)` — same per-save derivation pattern as bodies/exploration, so a given seed always starts with the same crew.
+- Exploration extended: the crew roll draws from the SAME per-planet rng stream as the resource/part haul (called after it in `explorePlanet`), so outcomes stay deterministic per save+planet and existing hauls are unchanged. Found members join the roster with origin = '<planet>, <system>'; each body can only be scanned once, so no duplicate joins.
+- New endpoint: `GET /api/crew` → `[{id,name,role,trait_good,trait_bad,origin}]` in join order (auto-initializes like the others). `POST /api/explore` responses now also carry `crewFound` (the joining member or null). OpenAPI spec in code (`lib/openapi.ts`) updated for both.
+- CREW tab now renders REAL data: fetches `/api/crew` on mount (Radix unmounts inactive tabs, so opening the tab always refetches — no polling), cards show name + role, the good (+) and bad (−) traits and an ORIGIN line. Placeholder crew constants removed for this tab only — other tabs keep theirs until their issues land.
+
 ## v0.4.0 — 2026-09-28 22:17
 - LOCAL SYSTEM tab — planet list + exploration to find things (issue #6): the first in-system game loop on top of issue #5's save/world foundation. Single-player, no auth, by design.
 - New tables (`lib/db/schema.ts` + DDL in `lib/db/client.ts`): `planets` (id/system_id/parent_id/name/type/hazard/explored — planets have parent_id NULL, moons point at their planet) and `inventory_items` (id/save_id/kind[name]/qty — the dumb-simple cargo hold SHIP SYSTEMS (#8) will spend from later).

app/api/crew/route.ts

@@ -0,0 +1,8 @@
+import { getGameDb } from '@/lib/db/client'
+import { getCrewState } from '@/lib/game/save'
+
+// The ship's crew roster: starting crew plus members found while exploring. Auto-initializes on first hit.
+export async function GET() {
+  const db = await getGameDb()
+  return Response.json(await getCrewState(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/crew-panel.tsx

@@ -0,0 +1,101 @@
+'use client'
+
+import { useEffect, useState } from 'react'
+import { Badge } from '@/components/ui/badge'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import type { CrewDto } from '@/lib/game/save'
+
+// CREW tab — the ship's roster: starting crew plus members found while exploring. Fetches
+// /api/crew on mount; Radix unmounts inactive tabs, so opening this tab always refetches
+// (no polling needed — turn-based game). Display-only for now: no dismiss/assign actions yet.
+
+interface CrewPanelProps {
+  narrow?: boolean
+}
+
+export function CrewPanel({ narrow }: CrewPanelProps) {
+  const [roster, setRoster] = useState<CrewDto[] | null>(null)
+  const [error, setError] = useState<string | null>(null)
+
+  useEffect(() => {
+    let cancelled = false
+    fetch('/api/crew')
+      .then(async (res) => {
+        if (!res.ok) throw new Error(`HTTP ${res.status}`)
+        return (await res.json()) as CrewDto[]
+      })
+      .then((r) => {
+        if (!cancelled) setRoster(r)
+      })
+      .catch((err: unknown) => {
+        if (!cancelled) setError(err instanceof Error ? err.message : String(err))
+      })
+    return () => {
+      cancelled = true
+    }
+  }, [])
+
+  if (error && !roster) {
+    return (
+      <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' }}>
+          CREW MANIFEST OFFLINE // {error.toUpperCase()}
+        </span>
+      </div>
+    )
+  }
+
+  if (!roster) {
+    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 CREW MANIFEST…</span>
+      </div>
+    )
+  }
+
+  return (
+    <div
+      style={{
+        display: 'grid',
+        gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)',
+        gap: '0.75rem',
+      }}
+    >
+      {roster.map((member) => (
+        <Card key={member.id}>
+          <CardHeader>
+            <div style={{ display: 'flex', alignItems: 'center' }}>
+              <CardTitle>{member.name}</CardTitle>
+              <Badge variant="ACTIVE" className="ml-auto">
+                ACTIVE
+              </Badge>
+            </div>
+            <p
+              style={{
+                fontSize: '0.6rem',
+                color: 'var(--text-muted)',
+                letterSpacing: '0.1em',
+                textTransform: 'uppercase',
+              }}
+            >
+              {member.role}
+            </p>
+          </CardHeader>
+          <CardContent style={{ display: 'flex', flexDirection: 'column', gap: '0.4rem' }}>
+            <div style={{ fontSize: '0.7rem', letterSpacing: '0.05em' }}>
+              <span style={{ color: 'var(--color-green)' }}>+ </span>
+              <span style={{ color: 'var(--text-secondary)' }}>{member.traitGood}</span>
+            </div>
+            <div style={{ fontSize: '0.7rem', letterSpacing: '0.05em' }}>
+              <span style={{ color: 'var(--color-red)' }}>- </span>
+              <span style={{ color: 'var(--text-secondary)' }}>{member.traitBad}</span>
+            </div>
+            <p style={{ fontSize: '0.6rem', color: 'var(--text-muted)', letterSpacing: '0.08em' }}>
+              ORIGIN // {member.origin.toUpperCase()}
+            </p>
+          </CardContent>
+        </Card>
+      ))}
+    </div>
+  )
+}

components/mission-control.tsx

@@ -3,21 +3,27 @@
 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'
 import { StatusGrid, type SystemEntry } from '@/components/ui/status-grid'
 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 { 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 and LOCAL SYSTEM tabs render live data (/api/world, /api/system); the other
+// WORLD MAP, LOCAL SYSTEM, CREW, SHIP SYSTEMS and SKILL TREE tabs render live data (/api/world,
-// tabs keep placeholder content until their own issues land. Single player, no auth, by design.
+// /api/system, /api/crew, /api/ship, /api/tech); the other tabs keep placeholder content until
+// their own issues land. Single player, no auth, by design.
 
 function useNarrow(threshold = 900): boolean {
   const [narrow, setNarrow] = useState(
@@ -37,36 +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 crew = [
-  { name: 'CMDR. E. VANCE', role: 'COMMANDER', good: 'STEADY UNDER PRESSURE', bad: 'RIGID — SLOW TO ADAPT' },
-  { name: 'LT. M. OKONKWO', role: 'PILOT', good: 'RECKLESS COURAGE', bad: 'SHORT FUSE' },
-  { name: 'DR. I. SORENSEN', role: 'MEDIC', good: 'CALM IN A CRISIS', bad: 'OVERCAUTIOUS' },
-  { name: 'R. "SPARK" DELACRUZ', role: 'ENGINEER', good: 'FIXES ANYTHING', bad: 'CARELESS WITH FUSES' },
-]
-
-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' },
@@ -95,6 +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)
@@ -103,6 +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={{
@@ -263,11 +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">
@@ -275,11 +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="HULL INTEGRITY" value={Math.min(100, (ship.systems.find((s) => s.type === 'HULL')?.level ?? 0) * 20)} />
-                  <Progress label="REACTOR OUTPUT" value={94} />
+                    <Progress label="REACTOR OUTPUT" value={Math.min(100, (ship.systems.find((s) => s.type === 'REACTOR')?.level ?? 0) * 20)} />
-                  <Progress label="CREW ROSTER / 6" value={50} />
+                    <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>
@@ -331,118 +371,19 @@ export function MissionControl() {
                     <LocalSystemPanel />
                   </TabsContent>
 
-                  {/* CREW TAB */}
+                  {/* CREW TAB — live data from /api/crew */}
                   <TabsContent value="crew" style={{ margin: 0, padding: '1rem' }}>
-                    <div
+                    <CrewPanel narrow={narrow} />
-                      style={{
-                        display: 'grid',
-                        gridTemplateColumns: narrow ? '1fr' : 'repeat(2, 1fr)',
-                        gap: '0.75rem',
-                      }}
-                    >
-                      {crew.map((member) => (
-                        <Card key={member.name}>
-                          <CardHeader>
-                            <div style={{ display: 'flex', alignItems: 'center' }}>
-                              <CardTitle>{member.name}</CardTitle>
-                              <Badge variant="ACTIVE" className="ml-auto">
-                                ACTIVE
-                              </Badge>
-                            </div>
-                            <p
-                              style={{
-                                fontSize: '0.6rem',
-                                color: 'var(--text-muted)',
-                                letterSpacing: '0.1em',
-                                textTransform: 'uppercase',
-                              }}
-                            >
-                              {member.role}
-                            </p>
-                          </CardHeader>
-                          <CardContent style={{ display: 'flex', flexDirection: 'column', gap: '0.4rem' }}>
-                            <div style={{ fontSize: '0.7rem', letterSpacing: '0.05em' }}>
-                              <span style={{ color: 'var(--color-green)' }}>+ </span>
-                              <span style={{ color: 'var(--text-secondary)' }}>{member.good}</span>
-                            </div>
-                            <div style={{ fontSize: '0.7rem', letterSpacing: '0.05em' }}>
-                              <span style={{ color: 'var(--color-red)' }}>- </span>
-                              <span style={{ color: 'var(--text-secondary)' }}>{member.bad}</span>
-                            </div>
-                          </CardContent>
-                        </Card>
-                      ))}
-                    </div>
                   </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
+                    <ShipSystemsPanel ship={ship} narrow={narrow} onChanged={setShip} researchedSlugs={researchedSlugs} />
-                      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>
                   </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
+                    <SkillTreePanel techs={techs} ship={ship} narrow={narrow} onResearched={setTechs} />
-                      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>
                   </TabsContent>
 
                   {/* MISSIONS TAB */}

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 }
@@ -7,7 +8,12 @@ interface PlanetDto { id: number; name: string; type: string; hazard: boolean; e
 interface InventoryItemDto { kind: string; name: string; qty: number }
 interface SystemState { systemId: number; systemName: string; planets: PlanetDto[]; inventory: InventoryItemDto[]; turn: number }
 interface FoundItem { kind: string; name: string; qty: number }
-interface ExploreResult extends SystemState { outcome: FoundItem[] }
+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 }
+
+const totalQty = (items: InventoryItemDto[], kind: string) => items.filter((i) => i.kind === kind).reduce((sum, i) => sum + i.qty, 0);
 
 test('landing page loads with the SpaceWanderer title', async ({ page }) => {
   await page.goto('/');
@@ -119,6 +125,136 @@ test('exploration yields finds that accumulate in the inventory', async ({ page
   }
 });
 
+test('CREW tab renders real roster cards, each showing both traits and an origin', async ({ page }) => {
+  const roster = (await (await page.request.get('/api/crew')).json()) as CrewDto[];
+  expect(roster.length).toBeGreaterThanOrEqual(2); // starting crew is always seeded
+
+  await page.goto('/');
+  await page.getByRole('tab', { name: 'CREW' }).click();
+
+  for (const member of roster) {
+    const heading = page.getByRole('heading', { name: member.name });
+    await expect(heading).toBeVisible();
+    // The card is the third div ancestor of the title (flex row → CardHeader → Card).
+    const card = heading.locator('xpath=ancestor::div[3]');
+    await expect(card.getByText(member.role)).toBeVisible();
+    await expect(card.getByText(member.traitGood)).toBeVisible();
+    await expect(card.getByText(member.traitBad)).toBeVisible();
+    await expect(card.getByText(`ORIGIN // ${member.origin.toUpperCase()}`)).toBeVisible();
+  }
+});
+
+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('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
@@ -8,11 +9,13 @@ 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.
+// Mirrors the /api/system response shape (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 }
 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[] }
 
 test('app survives a container restart (stack + volume persistence)', async ({ page }) => {
   test.setTimeout(180_000);
@@ -24,22 +27,13 @@ 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;
+  await jumpToFreshSystem(page);
-  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);
 
   // 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;
+    await jumpToFreshSystem(page); // prefer undiscovered territory — first-edge ping-pongs between exhausted systems
-    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);
     sysBefore = (await (await page.request.get('/api/system')).json()) as SystemState;
   }
   const targetPlanet = sysBefore.planets.find((p) => !p.explored)!;
@@ -47,6 +41,18 @@ test('app survives a container restart (stack + volume persistence)', async ({ p
   expect(exploreRes.status()).toBe(200);
   const sysExplored = (await exploreRes.json()) as SystemState;
 
+  // Crew baseline: the roster (starting crew + any finds so far) must survive too.
+  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
+
   // Restart the app container mid-run — the named DB volume must survive it.
   execSync(`docker compose ${composeArgs} restart space-wanderer`, { cwd: repoRoot, stdio: 'pipe' });
 
@@ -68,7 +74,7 @@ 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);
 
@@ -77,6 +83,18 @@ test('app survives a container restart (stack + volume persistence)', async ({ p
   expect(sysAfter.turn).toBe(sysExplored.turn);
   expect(sysAfter.planets.find((p) => p.id === targetPlanet.id)?.explored).toBe(true);
 
+  // Crew roster survived too: same members, traits and origins (no re-seed on restart).
+  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);
+
   // 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 (
@@ -61,6 +62,38 @@ CREATE TABLE IF NOT EXISTS inventory_items (
   qty INTEGER NOT NULL DEFAULT 1
 );
 
+CREATE TABLE IF NOT EXISTS crew (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  save_id INTEGER NOT NULL REFERENCES saves(id),
+  name TEXT NOT NULL,
+  role TEXT NOT NULL,
+  trait_good TEXT NOT NULL,
+  trait_bad TEXT NOT NULL,
+  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 events (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   save_id INTEGER NOT NULL REFERENCES saves(id),
@@ -88,6 +121,14 @@ 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', {
@@ -58,6 +61,53 @@ export const inventoryItems = sqliteTable('inventory_items', {
   qty: integer('qty').notNull().default(1),
 })
 
+// The ship's crew roster: the starting crew (seeded on new game) plus members found while
+// exploring planets/moons. Display-only for now — no dismiss/assign actions yet (#7 scope).
+export const crew = sqliteTable('crew', {
+  id: integer('id').primaryKey({ autoIncrement: true }),
+  saveId: integer('save_id').notNull().references(() => saves.id),
+  name: text('name').notNull(),
+  role: text('role').notNull(),
+  traitGood: text('trait_good').notNull(),
+  traitBad: text('trait_bad').notNull(),
+  // Where the member came from: 'STARTING CREW' or '<planet>, <system>' for found members.
+  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)],
+)
+
 // 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/crew.test.ts

@@ -0,0 +1,74 @@
+import { describe, expect, it } from 'vitest'
+import { CREW_CHANCE, generateStartingCrew, makeCrewName, rollCrewMember, startingCrewRng } from './crew'
+import { explorationRng } from './world'
+
+describe('generateStartingCrew', () => {
+  it('gives a new game 2–3 members, each with exactly one good and one bad trait', () => {
+    for (const seed of [1, 7, 42, 999]) {
+      const crew = generateStartingCrew(startingCrewRng(String(seed)))
+      expect(crew.length).toBeGreaterThanOrEqual(2)
+      expect(crew.length).toBeLessThanOrEqual(3)
+
+      for (const member of crew) {
+        expect(member.name.trim().length).toBeGreaterThan(0)
+        expect(member.role.trim().length).toBeGreaterThan(0)
+        expect(member.traitGood.trim().length).toBeGreaterThan(0)
+        expect(member.traitBad.trim().length).toBeGreaterThan(0)
+      }
+      // Names are unique within the crew; roles too (drawn without replacement).
+      expect(new Set(crew.map((m) => m.name)).size).toBe(crew.length)
+      expect(new Set(crew.map((m) => m.role)).size).toBe(crew.length)
+    }
+  })
+
+  it('is deterministic under a fixed seed and differs across seeds', () => {
+    const a = generateStartingCrew(startingCrewRng('42'))
+    expect(generateStartingCrew(startingCrewRng('42'))).toEqual(a) // same save → same crew
+    const b = generateStartingCrew(startingCrewRng('43'))
+    expect(JSON.stringify(b)).not.toBe(JSON.stringify(a)) // different seed → different crew
+  })
+})
+
+describe('rollCrewMember', () => {
+  it('finds a member with the documented probability and never reuses a taken name', () => {
+    const rng = startingCrewRng('42')
+    let found = 0
+    for (let i = 0; i < 1000; i++) found += rollCrewMember(rng, new Set<string>()) ? 1 : 0
+    // 18% ± a comfortable band — catches an inverted or missing chance without flaking.
+    expect(found).toBeGreaterThan(90)
+    expect(found).toBeLessThan(270)
+
+    const taken = new Set(['Ava Vance'])
+    for (let i = 0; i < 50; i++) {
+      const member = rollCrewMember(startingCrewRng(String(i)), taken)
+      if (member) expect(member.name).not.toBe('Ava Vance') // never reuses a roster name
+    }
+  })
+
+  it('is deterministic per save+planet when drawn from the exploration stream', () => {
+    const first = rollCrewMember(explorationRng('42', 13), new Set<string>())
+    expect(rollCrewMember(explorationRng('42', 13), new Set<string>())).toEqual(first) // same save+planet → same result
+
+    // Across many planets both outcomes occur (someone is found, someone isn't).
+    let found = 0
+    for (let planetId = 1; planetId <= 200; planetId++) {
+      if (rollCrewMember(explorationRng('42', planetId), new Set<string>())) found++
+    }
+    expect(found).toBeGreaterThan(0)
+    expect(found).toBeLessThan(200)
+  })
+
+  it('keeps the crew chance documented and sane', () => {
+    expect(CREW_CHANCE).toBeGreaterThanOrEqual(0.15)
+    expect(CREW_CHANCE).toBeLessThanOrEqual(0.2)
+  })
+})
+
+describe('makeCrewName', () => {
+  it('never reuses a taken name and always terminates', () => {
+    const rng = startingCrewRng('7')
+    const taken = new Set<string>()
+    for (let i = 0; i < 40; i++) makeCrewName(rng, taken)
+    expect(taken.size).toBe(40)
+  })
+})

lib/game/crew.ts

@@ -0,0 +1,90 @@
+// Pure, seeded crew generation — no DB, no Date, no Math.random. Same seed → same starting
+// crew; the exploration crew roll draws from the caller's per-planet rng stream so a found
+// member is deterministic per save+planet (same derivation as the resource/part haul).
+
+import { mulberry32 } from './world'
+
+export interface CrewMember {
+  name: string
+  role: string
+  traitGood: string
+  traitBad: string
+}
+
+const FIRST_NAMES = [
+  'AVA', 'BEN', 'CASS', 'DANA', 'ELI', 'FERN', 'GIDEON', 'HALYA',
+  'IVAR', 'JUNO', 'KAI', 'LORE', 'MARA', 'NICO', 'ODESSA', 'PETRA',
+]
+
+const LAST_NAMES = [
+  'VANCE', 'OKONKWO', 'SORENSEN', 'DELACRUZ', 'HALLOWAY', 'IBARRA', 'KOVAC', 'LINDQVIST',
+  'MERCER', 'NADEAU', 'ORLOV', 'QUINTANA', 'REYES', 'STALKE', 'TANAKA', 'UNDERWOOD',
+  'VALDEZ', 'WHITLOCK', 'YAMADA', 'ZUBEROV', 'ASHFORD', 'BLACKWELL',
+]
+
+const ROLES = ['COMMANDER', 'PILOT', 'ENGINEER', 'MEDIC', 'NAVIGATOR', 'SCIENTIST', 'GUNNER', 'TECHNICIAN']
+
+const GOOD_TRAITS = [
+  'STEADY UNDER PRESSURE', 'RECKLESS COURAGE', 'CALM IN A CRISIS', 'FIXES ANYTHING',
+  'SHARP SHOOTER', 'READS STARS BLIND', 'QUICK HANDS', 'IRON WILL',
+  'FINDS HIDDEN THINGS', 'TALKS TO ANYONE',
+]
+
+const BAD_TRAITS = [
+  'RIGID — SLOW TO ADAPT', 'SHORT FUSE', 'OVERCAUTIOUS', 'CARELESS WITH FUSES',
+  'SLOWS THE CREW DOWN', 'ARGUES WITH EVERYONE', 'FORGETS TO EAT', 'JINXED IN A DOGFIGHT',
+  'HOARDS RATIONS', 'DOUBTS THE CAPTAIN',
+]
+
+const STARTING_CREW_MIN = 2
+const STARTING_CREW_SPREAD = 2 // 2..3 starting members
+export const CREW_CHANCE = 0.18 // a scan finds a crew member who joins the ship (~1 in 5-6 scans)
+
+function title(word: string): string {
+  return word.charAt(0) + word.slice(1).toLowerCase()
+}
+
+function pick<T>(rng: () => number, arr: T[]): T {
+  return arr[Math.floor(rng() * arr.length)]
+}
+
+// A name unique against `taken` (the current roster), claimed into the set on success.
+// 16×22 = 352 combinations — a roster realistically never approaches that size.
+export function makeCrewName(rng: () => number, taken: Set<string>): string {
+  for (;;) {
+    const name = `${title(pick(rng, FIRST_NAMES))} ${pick(rng, LAST_NAMES)}`
+    if (!taken.has(name)) {
+      taken.add(name)
+      return name
+    }
+  }
+}
+
+// The crew a new game starts with: 2–3 members, unique names and roles (roles are drawn
+// without replacement). Pure — the caller derives the rng from the save seed.
+export function generateStartingCrew(rng: () => number): CrewMember[] {
+  const taken = new Set<string>()
+  const roles = [...ROLES]
+  const crew: CrewMember[] = []
+  for (let i = 0; i < STARTING_CREW_MIN + Math.floor(rng() * STARTING_CREW_SPREAD); i++) {
+    const role = roles.splice(Math.floor(rng() * roles.length), 1)[0]
+    crew.push({ name: makeCrewName(rng, taken), role, traitGood: pick(rng, GOOD_TRAITS), traitBad: pick(rng, BAD_TRAITS) })
+  }
+  return crew
+}
+
+// The exploration crew roll: with CREW_CHANCE a member is found and joins the ship. Draws
+// from the SAME per-planet rng stream as the resource/part haul (called after it in
+// save.ts), so the outcome stays deterministic per save+planet. `taken` is the current
+// roster's names, keeping every name on the ship unique.
+export function rollCrewMember(rng: () => number, taken: Set<string>): CrewMember | null {
+  if (rng() >= CREW_CHANCE) return null
+  const role = pick(rng, ROLES)
+  return { name: makeCrewName(rng, taken), role, traitGood: pick(rng, GOOD_TRAITS), traitBad: pick(rng, BAD_TRAITS) }
+}
+
+// Independent PRNG stream for the starting crew of one save (same pattern as bodyRng /
+// explorationRng in world.ts — a fixed offset keeps it away from every other derivation).
+export function startingCrewRng(seed: string): () => number {
+  return mulberry32((Number(seed) + 0x51ed270b) >>> 0)
+}

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

@@ -2,9 +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 { getSystemState, explorePlanet, getWorldState, jumpToSystem, type WorldState } from './save'
+import { generateStartingCrew, rollCrewMember, startingCrewRng } from './crew'
+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[] = []
@@ -228,3 +232,184 @@ describe('explorePlanet', () => {
     expect(state.turn).toBe(planetIds.length) // one turn per scan
   })
 })
+
+describe('getCrewState', () => {
+  it('seeds a starting crew of 2–3 members derived from the save seed', async () => {
+    const { db } = await freshFile()
+    const crew = await getCrewState(db) // ensureSave runs inside, so this also seeds the crew
+
+    expect(crew.length).toBeGreaterThanOrEqual(2)
+    expect(crew.length).toBeLessThanOrEqual(3)
+    for (const member of crew) {
+      expect(member.origin).toBe('STARTING CREW')
+      expect(member.name.trim()).not.toBe('')
+      expect(member.role.trim()).not.toBe('')
+      expect(member.traitGood.trim()).not.toBe('')
+      expect(member.traitBad.trim()).not.toBe('')
+    }
+
+    // The roster is exactly the pure generation for this save's seed.
+    const [save] = await db.db.select().from(schema.saves)
+    const expected = generateStartingCrew(startingCrewRng(save.seed))
+    expect(crew.map((c) => c.name)).toEqual(expected.map((m) => m.name))
+    expect(crew.map((c) => c.role)).toEqual(expected.map((m) => m.role))
+    expect(crew.map((c) => [c.traitGood, c.traitBad])).toEqual(expected.map((m) => [m.traitGood, m.traitBad]))
+  })
+})
+
+describe('explorePlanet crew finds', () => {
+  it('lands a found member in the roster with the planet+system origin and never joins twice (known seed)', async () => {
+    // Hand-built save with a known seed so the crew roll is recomputable offline.
+    const { db } = await freshFile()
+    const [save] = await db.db.insert(schema.saves).values({ seed: '42', turn: 0, createdAt: new Date().toISOString() }).returning()
+    const [sys] = await db.db
+      .insert(schema.solarSystems)
+      .values({ saveId: save.id, name: 'Test System', x: 50, y: 50, discovered: true, isCurrent: true })
+      .returning({ id: schema.solarSystems.id })
+
+    // Find a small planet id whose exploration roll finds crew (deterministic — recomputed here,
+    // mirroring save.ts: the item haul draws first, then the crew roll on the same stream).
+    let crewPlanetId = -1
+    for (let id = 1; id <= 50 && crewPlanetId === -1; id++) {
+      const rng = explorationRng('42', id)
+      rollExploration(rng)
+      if (rollCrewMember(rng, new Set<string>())) crewPlanetId = id
+    }
+    expect(crewPlanetId).toBeGreaterThan(0)
+
+    const planetName = `P${crewPlanetId}`
+    for (let i = 1; i <= crewPlanetId; i++) {
+      await db.db.insert(schema.planets).values({ systemId: sys.id, parentId: null, name: `P${i}`, type: 'ROCKY', hazard: false })
+    }
+
+    const before = await getCrewState(db) // empty — this save was hand-built, no starting crew seeded
+    const result = await explorePlanet(db, crewPlanetId)
+
+    expect(result.crewFound).not.toBeNull()
+    const expectedRng = explorationRng('42', crewPlanetId)
+    rollExploration(expectedRng) // consume the item haul draws first, exactly as save.ts does
+    const expectedMember = rollCrewMember(expectedRng, new Set<string>())! // same save+planet → same member
+    expect(result.crewFound!.name).toBe(expectedMember.name)
+    expect(result.crewFound!.role).toBe(expectedMember.role)
+    expect([result.crewFound!.traitGood, result.crewFound!.traitBad]).toEqual([expectedMember.traitGood, expectedMember.traitBad])
+    expect(result.crewFound!.origin).toBe(`${planetName}, Test System`)
+
+    const after = await getCrewState(db)
+    expect(after.length).toBe(before.length + 1) // exactly one join
+    expect(after.find((c) => c.id === result.crewFound!.id)).toMatchObject({ name: expectedMember.name, origin: `${planetName}, Test System` })
+
+    // The body is already explored → a second scan is rejected and no duplicate joins.
+    await expect(explorePlanet(db, crewPlanetId)).rejects.toMatchObject({ status: 409 })
+    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

@@ -2,6 +2,9 @@ import { eq } from 'drizzle-orm'
 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 { 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.
@@ -44,20 +47,36 @@ 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
+// The bodies of one system (planets + moons), derived from (seed, system id) via bodyRng —
-// never left without worlds to explore. Bodies derive from (seed, system id) via bodyRng —
+// independent of generation order and every other system. Shared by new-game creation and the
-// independent of generation order and every other system.
+// 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))) {
+  await insertBodiesForSystem(db, row.id, seed)
-    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 })
-    }
-  }
   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)
@@ -67,17 +86,51 @@ async function insertRoutes(db: GameDb, edges: [number, number][], resolve: (ind
   }
 }
 
-// Creates the save + starting region when the DB has none. No-op otherwise — safe to call
+// Seeds the starting crew for a fresh save: 2–3 members derived from the seed alone.
-// on every request (single player, one process: check-then-insert cannot race in practice).
+async function seedStartingCrew(db: GameDb, saveId: number, seed: string): Promise<void> {
+  for (const member of generateStartingCrew(startingCrewRng(seed))) {
+    await db.db.insert(schema.crew).values({ saveId, name: member.name, role: member.role, traitGood: member.traitGood, traitBad: member.traitBad, origin: 'STARTING CREW' })
+  }
+}
+
+// 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). When #10 adds
+// seeding, bump SCHEMA_VERSION and append a step here.
+export const SCHEMA_VERSION = 5 // v1: save + start region only · v2: bodies for every system · v3: starting crew · v4: starting ship · v5: tech tree
+
+// 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[] = []
@@ -86,11 +139,42 @@ 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 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 (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)
@@ -210,13 +294,32 @@ export async function getSystemState(db: GameDb): Promise<SystemState> {
   return readSystemState(db)
 }
 
+// --- Crew roster --------------------------------------------------------------
+
+export interface CrewDto {
+  id: number
+  name: string
+  role: string
+  traitGood: string
+  traitBad: string
+  origin: string // 'STARTING CREW' or '<planet>, <system>' for members found while exploring
+}
+
+// The full roster in join order (starting crew first, then finds). Auto-initializes like the other reads.
+export async function getCrewState(db: GameDb): Promise<CrewDto[]> {
+  await ensureSave(db)
+  return (await db.db.select().from(schema.crew)).map((c) => ({ id: c.id, name: c.name, role: c.role, traitGood: c.traitGood, traitBad: c.traitBad, origin: c.origin }))
+}
+
 export interface ExploreResult extends SystemState {
   outcome: FoundItem[] // what this scan found (may be empty — some scans find nothing)
+  crewFound: CrewDto | null // a member who joined the ship on this scan (null when none)
 }
 
 // Scan one body of the save: deterministic haul from (seed, planet id), marks it explored,
-// costs a turn, accumulates finds into inventory and writes an event. Any existing planet
+// costs a turn, accumulates finds into inventory and writes an event. The same per-planet
-// may be scanned (the UI only offers the current system's rows).
+// rng stream also rolls for a crew member (~18% of scans) who joins the roster. Any existing
+// planet may be scanned (the UI only offers the current system's rows).
 export async function explorePlanet(db: GameDb, planetId: number): Promise<ExploreResult> {
   await ensureSave(db)
   const [save] = await db.db.select().from(schema.saves).limit(1)
@@ -225,7 +328,10 @@ export async function explorePlanet(db: GameDb, planetId: number): Promise<Explo
   if (!target) throw new ExploreError(404, `Unknown planet ${planetId}`)
   if (target.explored) throw new ExploreError(409, `${target.name} was already explored`)
 
-  const outcome = rollExploration(explorationRng(save.seed, target.id))
+  const rng = explorationRng(save.seed, target.id)
+  const outcome = rollExploration(rng) // resource/part haul first…
+  const takenNames = new Set((await db.db.select().from(schema.crew)).map((c) => c.name))
+  const foundMember = rollCrewMember(rng, takenNames) // …then the crew roll on the same stream
   const turn = save.turn + 1
 
   await db.db.update(schema.planets).set({ explored: true }).where(eq(schema.planets.id, target.id))
@@ -239,10 +345,19 @@ export async function explorePlanet(db: GameDb, planetId: number): Promise<Explo
     }
   }
 
+  let crewFound: CrewDto | null = null
+  if (foundMember) {
+    const systems = await db.db.select().from(schema.solarSystems)
+    const systemName = systems.find((s) => s.id === target.systemId)?.name ?? 'unknown system'
+    const [row] = await db.db.insert(schema.crew).values({ saveId: save.id, name: foundMember.name, role: foundMember.role, traitGood: foundMember.traitGood, traitBad: foundMember.traitBad, origin: `${target.name}, ${systemName}` }).returning()
+    crewFound = { id: row.id, name: row.name, role: row.role, traitGood: row.traitGood, traitBad: row.traitBad, origin: row.origin }
+  }
+
   const foundText = outcome.length > 0 ? outcome.map((i) => `${i.qty}× ${i.name}`).join(', ') : 'nothing'
+  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}`, createdAt: new Date().toISOString() })
+  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 persist(db)
 
-  return { ...(await readSystemState(db)), outcome }
+  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

@@ -5,14 +5,72 @@ import { openApiSpec } from './openapi';
 describe('OpenAPI spec', () => {
   it('documents every public endpoint', () => {
     expect(Object.keys(openApiSpec.paths).sort()).toEqual([
+      '/api/crew',
       '/api/explore',
       '/api/jump',
+      '/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 /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');
+    expect((crew.items as { $ref: string }).$ref).toBe('#/components/schemas/CrewMember');
+
+    const member = openApiSpec.components.schemas.CrewMember.properties;
+    expect(Object.keys(member)).toEqual(['id', 'name', 'role', 'trait_good', 'trait_bad', 'origin']);
+
+    const exploreResult = openApiSpec.components.schemas.ExploreResult as { allOf: unknown[] };
+    const extra = (exploreResult.allOf[1] as { properties: Record<string, unknown> }).properties;
+    expect(Object.keys(extra)).toEqual(['outcome', 'crewFound']);
+  });
+
   it('describes the system endpoints as SystemState in and out', () => {
     const system = openApiSpec.paths['/api/system'].get.responses[200].content['application/json'].schema;
     expect(system.$ref).toBe('#/components/schemas/SystemState');

lib/openapi.ts

@@ -168,6 +168,292 @@ export const openApiSpec = {
         },
       },
     },
+    '/api/crew': {
+      get: {
+        summary: 'Crew roster',
+        description:
+          'The ship crew in join order — the starting crew (seeded on new game) plus members found while exploring planets/moons. Each member has one good and one bad trait and an origin. Auto-initializes a new game when no save exists yet.',
+        operationId: 'getCrew',
+        responses: {
+          200: {
+            description: 'Crew roster',
+            content: {
+              'application/json': {
+                schema: { type: 'array', items: { $ref: '#/components/schemas/CrewMember' } },
+              },
+            },
+          },
+        },
+      },
+    },
+    '/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' },
+              },
+            },
+          },
+        },
+      },
+    },
   },
   components: {
     schemas: {
@@ -245,6 +531,93 @@ export const openApiSpec = {
         },
         required: ['kind', 'name', 'qty'],
       },
+      CrewMember: {
+        type: 'object',
+        properties: {
+          id: { type: 'integer' },
+          name: { type: 'string' },
+          role: { type: 'string', description: 'Ship role, e.g. PILOT or ENGINEER' },
+          trait_good: { type: 'string', description: 'The member good trait' },
+          trait_bad: { type: 'string', description: 'The member bad trait' },
+          origin: { type: 'string', description: "'STARTING CREW' or '<planet>, <system>' for members found while exploring" },
+        },
+        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'],
+      },
+      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: {
@@ -278,8 +651,12 @@ export const openApiSpec = {
                 description: 'What this scan found — may be empty (some scans find nothing)',
                 items: { $ref: '#/components/schemas/FoundItem' },
               },
+              crewFound: {
+                description: 'A crew member who joined the ship on this scan (~18% of scans), null when none',
+                anyOf: [{ $ref: '#/components/schemas/CrewMember' }, { type: 'null' }],
               },
-            required: ['outcome'],
+            },
+            required: ['outcome', 'crewFound'],
           },
         ],
       },

package.json

@@ -1,6 +1,6 @@
 {
   "name": "space-wanderer",
-  "version": "0.4.0",
+  "version": "0.7.0",
   "private": true,
   "scripts": {
     "dev": "next dev -p 3000",