AGENTS.md

@@ -104,7 +104,7 @@ history/
 │   │   ├── <name>.ts       #   one module per ability: wars / takeovers / leaders / nuclear /
 │   │   │                   #     ideology / industry / economy / hybrid / disasters (v0.41.0 #63) /
 │   │   │                   #     migration (v0.42.0 #64)
-│   │   ├── *.test.ts       #   per-ability unit tests (registry.test.ts pins the 10-ability contract)
+│   │   ├── *.test.ts       #   per-ability unit tests (registry.test.ts pins the 12-ability contract)
 │   │   └── goldens/        #   pinned prompt goldens (system-no-tool / system-tool / user)
 │   └── *.test.ts           # unit tests (vitest)
 └── src/
@@ -583,6 +583,52 @@ history/
   12 named zones**, sole-control semantics, contest-by-higher-military, and a durable
   `seaZones` list — a cleaner, more deterministic model that the LLM can reason about without
   inventing zone names each turn.
+- **Contested regions / frontlines — a `TurnResult.contested` lever opening/resolving war frontlines: a THIRD region state in no nation's `territory` and not in `unowned` (v0.44.0, #66).**
+  `TurnResult.contested = ContestedOps = { open: ContestOp[]; resolve: string[] }` (required,
+  default `{ open: [], resolve: [] }`); `ContestOp = { regionKey, parties }` where `regionKey` is
+  a region key or resolvable name and `parties` are TWO OR MORE nation refs (ids or names, via
+  the shared `resolveNationRef`). Like the `sea` / `industry` layers this is **durable**: it owns
+  the `GameState.contested: ContestedRegion[]` field (`ContestedRegion = { regionKey, parties }`
+  — `parties` store the RESOLVED nation ids; required, `[]` at creation; a legacy SQLite row
+  without the field loads as `[]` — via the generic `ABILITIES` `stateFields` loop in `db.ts`,
+  no `db.ts` code change needed). `applyContested` (run LAST in the `ABILITIES` loop, after
+  territory / wars / economy / sea — it sees the final post-claim ownership) runs **RESOLVE
+  first, then OPEN**: a `resolve` removes a currently-contested key and **releases it to no
+  man's land** (into `unowned`, out of any territory, `regionStats` deleted) — UNLESS a
+  concurrent winning claim by one of the contesting **parties** already re-owned it this turn
+  (the only claim the territory step permits on a contested key), in which case it stays owned
+  and keeps (or re-inits) its `regionStats`; an `open` makes a region a frontline only when it
+  is **contestable** — a **sole owner** at war (a shared **active** `War`) with at least one
+  party, or a **no-man's-land** region (0 owners AND in `unowned`) whose two parties are at war
+  with each other — a 2+-owner key or an owner not at war with any party is **dropped**
+  (an armistice/ended war does not count); on a successful open the key is **stripped from its
+  owner's `territory` (or from `unowned`)**, its `regionStats` entry deleted, and a
+  `{ regionKey, parties }` entry added to `next.contested` (**unique by `regionKey`** — a
+  re-open replaces a kept entry), with the stripped owner's derived stats re-derived (same
+  0-region / no-entry guards). The **sacrosanct sole-ownership invariant is never broken**: a
+  contested key is in **no** territory (never two) and is **never** in `unowned` while
+  contested (the two states are mutually exclusive). The **territory step in `engine.ts` is
+  guarded**: a normal `gain` on a currently-contested key is **dropped** unless this same turn
+  resolves the contest AND the gainer is one of the contesting parties (a party re-claim) — a
+  still-contested key is never a valid normal-claim target. The **map (client-only, like
+  no-man's-land)**: `WorldMap` renders a contested key in the distinct visible
+  `CONTESTED_FILL` / `CONTESTED_STROKE` (orange "hot" frontline) with a `"Contested: A vs B"`
+  hover sub-line (names from `GameState.contested`; a removed party degrades to a dash) — the
+  contested check runs **first** (before unowned / owned); the server `RegionMap` stays
+  owned-vs-absent (it never knows about contested). **The map legend stays at 7 items** (it is
+  derived from the `RegionMap` owners only — a contested key is absent from the `RegionMap`, so
+  no new legend entry; e2e legend assertions are unaffected). `isMeaningful` is
+  `open.length > 0 || resolve.length > 0`; the system prompt documents the field + constraints
+  (at most 1–2 contested-region changes per turn, each narrated in `events`); the user payload
+  carries the current frontlines (region key + party **names**) **only when non-empty** —
+  `payload()` → `{}` on a fresh / no-frontline world (unlike `sea`, which always emits). The
+  **stub never** opens or resolves a frontline (`{ open: [], resolve: [] }`), so e2e (CI,
+  `LLM_STUB=1`) is unaffected and the path is unit-tested only
+  (`server/abilities/contested.test.ts`, 52 tests, each asserting the sole-ownership invariants).
+  **Design note (deviation from the issue body):** the Gitea #66 body sketched a **two-owner**
+  `disputed` / `fronts` design that "relaxes sole-ownership"; the implemented, approved design
+  is this **third region state** (a contested key in NO territory, sole-ownership preserved)
+  with `open` / `resolve` ops and a minimum of two contesting parties.
 - **Map click → dossier target (owner resolved from the RegionMap, by region key).**
   Clicking a sub-region does NOT open a popup — it switches the dossier to that sub-region's
   owning nation (`focusNation(ownerId, {name})` in `App.tsx`, which also records which region was

CHANGELOG.md

@@ -2,6 +2,20 @@
 
 All notable changes to **History** are listed here, newest first.
 
+## v0.44.0 — 2026-10-16 15:10
+- **#66: Contested regions / frontlines — a `TurnResult.contested` lever letting the LLM declare a region a **contested** war frontline (a **third region state**: in **no** nation's `territory` and **not** in `unowned` / no-man's-land) and resolve existing frontlines.** It lands as the **12th ability** of the v0.40.0 modular system, in a new `server/abilities/contested.ts` module, **registered last** in the `ABILITIES` registry (after `sea`). Like the `sea` and `industry` layers it is **durable**: `GameState.contested` persists across turns and in SQLite. It is a **pure territory-state** layer — the contested key simply *leaves* ownership (sole ownership is never broken: a key is in at most one `territory`), it is never placed into two territories, and it never touches borders directly.
+  - **Types (`shared/protocol.ts`).** New `ContestOp` (`{ regionKey; parties }` — `regionKey` is a region key or resolvable name, `parties` are two or more nation refs (ids or names)), `ContestedOps` (`{ open: ContestOp[]; resolve: string[] }`), and `ContestedRegion` (`{ regionKey; parties }` — `parties` store the **resolved** nation ids); `TurnResult.contested` is **required**, placed between `sea` and `markers`, default `{ open: [], resolve: [] }`. New `CONTESTED_FILL = '#f97316'` / `CONTESTED_STROKE` (the distinct visible frontline fill/stroke for the map — a reddish/orange "hot" frontline on the dark basemap, clearly distinct from a nation color and from the no-man's-land grey) and `contestedTooltipLabel(parties)` (a short `"Contested: A vs B"` hover sub-line; a missing party name degrades to a dash, never crashes). `ContestedRegion` is imported into `shared/types.ts`; `GameState.contested: ContestedRegion[]` is **required** (`[]` at creation; a legacy SQLite row without the field loads as `[]` — additive, never wiped, via the generic `ABILITIES` `stateFields` loop in `db.ts` — no `db.ts` code change needed).
+  - **Ability module (`server/abilities/contested.ts`).** `field: 'contested'`; `default()` / `stub()` → a **fresh** `{ open: [], resolve: [] }` each call; `validate` wraps the exported `validateContestedOps` (defensive, never throws — accepts the `{ open, resolve }` object; an `open` op needs a non-empty `regionKey` (trimmed, ≤120) and **two or more** non-empty `party` refs (each trimmed, ≤200), a `resolve` entry a non-empty key (trimmed, ≤120); missing / malformed → dropped; a missing / malformed top-level object yields `{ open: [], resolve: [] }`); `apply` runs the exported `applyContested`; `schemaLine()` / `constraint()` supply the prompt text; **`payload()` → `{ contested: [{ regionKey, parties: [NAMES] }] }`** (the current frontlines with party **names** resolved from the stored ids) **only when non-empty** — `{}` on a fresh / no-frontline world (like the turn-transient layers, unlike `sea` which always emits); `isMeaningful` = `open.length > 0 || resolve.length > 0`; **`stateFields: ['contested']`** (the durable `GameState` field, for the `db.ts` legacy-row migration).
+  - **Open semantics (`applyContested`, OPEN phase).** Each `open` op's `regionKey` resolves to a concrete key (exact key first, then a unique case-insensitive name via the region manifest — with no manifest loaded the raw string is accepted; a key absent from the loaded manifest is dropped). Its `parties` resolve via the shared `resolveNationRef` (id first, then a unique name; unresolvable / ambiguous refs dropped, order preserved, duplicates removed) — an op left with **fewer than two distinct resolved parties** is dropped. A region is **contestable** only when either (a) it has a **sole owner** that is at war (a shared **active** `War`) with at least one of the parties, or (b) it has **zero owners AND is in `unowned`** (no man's land) and **two of the parties are at war with each other**. A region with **two or more owners** (corrupt), or whose owner is **not at war with any party**, is never contestable (dropped — an ended / armistice war does not count). On a successful open the key is **removed from its sole owner's `territory`** (or from `unowned` for a no-man's-land region), its `regionStats` entry is **deleted**, and a `{ regionKey, parties: [ids] }` entry is added to `next.contested` (**unique by `regionKey`** — a re-open replaces any kept entry for the same key). The stripped owner's derived `stats` are **re-derived** (the same 0-region / no-entry guards as the other layers, so a 0-region owner keeps its directly-mutated value).
+  - **Resolve semantics (`applyContested`, RESOLVE phase — runs FIRST).** Each key in `resolve` that is currently in `next.contested` is removed and its region **released to no man's land** (out of any territory, into `unowned`, `regionStats` deleted) — **UNLESS a concurrent winning claim by one of the contesting parties** already re-owned it this turn (the only claim the territory step permits on a contested key), in which case it **stays owned** and its `regionStats` is **kept** (or **re-initialised** as a copy of the owner's stats if absent). A key that is not currently contested is ignored (no-op). A resolved key owned by a **non-party** (defensive) is released as above.
+  - **Territory-step guard (`engine.ts applyTurnResult`).** A **currently-contested** key (in `state.contested`) sits in no nation's territory, so a normal `gain` would otherwise be treated as a free re-claim. The claims step is guarded: a normal claim on a contested key proceeds **only** when this same turn `resolve`s the contest **AND** the gainer is one of the contesting **parties** (a party re-claim); otherwise the frontline **stays contested** for the contested layer (which runs later in the turn) to decide its fate. A still-contested key is therefore never a valid normal-claim target.
+  - **Map (client `WorldMap.tsx`).** The contested state is decided by the client from `GameState.contested` (like no-man's-land), **never by the `RegionMap`** (which stays owned-vs-absent). A contested key is rendered with the distinct `CONTESTED_FILL` / `CONTESTED_STROKE` and a `"Contested: A vs B"` hover sub-line; the contested check runs **first** (before unowned / owned) in the fill-resolution, and the hover handler resolves the party names from `GameState.contested`. **The map legend stays at 7 items** (it is derived from the `RegionMap` owners only — a contested key is absent from the `RegionMap`, so it adds no legend entry — e2e legend assertions unaffected). `App.tsx` passes `contested={game.contested ?? []}` to `<WorldMap>`.
+  - **Registry & prompt.** `contested` is added **last** in `ABILITIES` (existing order untouched — the 12th entry); the system prompt gains the `contested` schema line and its constraint bullet ("a contested region is in NO nation's territory (never two) and is never no man's land while contested; at most 1–2 contested-region changes per turn, each narrated in `events`"); the user prompt gains `"contested"` (region key + party **names**) **only when the list is non-empty** (the one durable ability whose `payload()` can be `{}`). The two committed system-prompt **goldens** (`system-no-tool.txt`, `system-tool.txt`) are regenerated (each gains exactly the new `contested` schema line after `sea` + constraint bullet before the "Prefer 1-4 events" bullet); the **`user.txt` golden gains a `"contested"` entry** (the sample `b-r1` frontline with party names) as a new key after `seaZones`.
+  - **Tests.** New `server/abilities/contested.test.ts` (**52 tests**): the `CONTESTED_FILL` / `CONTESTED_STROKE` / `contestedTooltipLabel` surface; `validateContestedOps` (shape / leniency / drops / field caps / malformed top-level); `applyContested` OPEN (sole-owner-at-war with owner-as-party / party-not-owner, owner-not-at-war drop, no-man's-land open + NML-with-warring-parties + not-in-unowned drop, corrupt 2-owner drop, armistice-not-a-war drop, distinct-party / unresolvable / ambiguous drops, region-name + party-name resolve, manifest-gated key drop, owner stats re-derive + 0-region guard, two-opens-on-same-key, multi-key open); RESOLVE (release-to-NML, party-re-claim keeps + re-inits stats, non-party-owner release, multi-frontline, non-contested no-op, empty no-op); ordering (re-open replaces, resolve-then-open from NML, still-contested not re-openable, combined apply); and the ability const contract (field, `stateFields`, fresh `default()`/`stub()`, `isMeaningful`, `payload()` id→name / missing-nation fallback / `{}` when empty, `validate` wrapping, `apply` ctx wiring). Every apply test asserts the **sole-ownership invariants** (no key in >1 territory; a contested key in no territory and not unowned; an unowned key in no territory and not contested). `registry.test.ts` is updated for the **12-ability** contract (order, distinct fields, `fullDefaultTurn()`, `meaningfulFor`, durable `stateFields`, composes 13 / `extended[12]`, re-export pin, user-golden 15th arg). New `db.test.ts` legacy-row test (a pre-v0.44 save without `contested` loads with `[]`).
+  - **Design note (deviation from the issue body).** The Gitea #66 body sketched a **two-owner** design (`disputed` regions with `fronts`, explicitly "relaxing sole-ownership"). The approved, implemented design is a **third region state**: a contested key is in **no** nation's `territory` and not in `unowned` (sole ownership is preserved — a key is never in two territories), with `open` / `resolve` ops and a **minimum of two contesting parties** tied to an active war. This keeps the engine's sacrosanct sole-ownership invariant intact while still modelling a war frontline.
+- **Guarantees.** No new runtime deps, `shared/` keeps zero runtime deps, no `@turf`/`@types/geojson` in any `.ts`. No engine randomness (the LLM declares; the engine applies fixed, deterministic rules). All existing unit tests green (additive); e2e (CI, `LLM_STUB=1`) unaffected (the stub is contested-inert — it never opens or resolves a frontline, and the map legend stays at 7).
+- **Version** bumped `0.43.0 → 0.44.0`.
+
 ## v0.43.0 — 2026-10-16 12:09
 - **#65: Sea control — a `TurnResult.sea` lever letting the LLM declare sole control over a fixed set of 12 named sea zones (North Atlantic, South Atlantic, Pacific, Indian, Mediterranean, North Sea, Baltic, Arctic, Black Sea, Gulf of Mexico, Red Sea, Sargasso), with a deterministic per-turn +1 military / +1 economy bonus for the controlling nation.** It is a **durable** feature (unlike the turn-transient `hybrid` / `disasters` / `migration` layers): `GameState.seaZones` persists across turns and in SQLite, and the user payload **always** carries the current `seaZones` list (even when empty) so the model knows who controls what. It lands as the **11th ability** of the v0.40.0 modular system, in a new `server/abilities/sea.ts` module, **registered last** in the `ABILITIES` registry (after `migration`). Sea control is fully **parallel to but independent of land**: it never touches `territory` / `unowned`, and moving land never touches a sea zone.
   - **Types (`shared/protocol.ts`).** New `SEA_ZONES` (a frozen array of 12 `{ id, name }` pairs), `SEA_ZONE_IDS` (a `ReadonlySet` of all 12 ids), `isSeaZoneId(id)` (type guard), `seaZoneName(id)` (human-readable name; unknown → raw), `SeaControlOp` (`{ zone; by }`), and `SeaOps` (`{ control: SeaControlOp[] }`); `TurnResult.sea` is **required**, placed between `migration` and `markers`, default `{ control: [] }`. New `SeaZoneClaim` (`{ zone; by }`) in `shared/types.ts`; `GameState.seaZones: SeaZoneClaim[]` is **required** (`[]` at creation; a legacy SQLite row without the field loads as `[]` — additive, never wiped, via the generic `ABILITIES` `stateFields` loop in `db.ts` — no `db.ts` code change needed).

package.json

@@ -1,6 +1,6 @@
 {
   "name": "history",
-  "version": "0.43.0",
+  "version": "0.44.0",
   "private": true,
   "type": "module",
   "description": "AI-driven alternate-history simulator — the LLM is the world engine (Pax Historia style).",

server/abilities/contested.ts

@@ -0,0 +1,301 @@
+// The CONTESTED (contested regions / frontlines) ability (v0.44.0, #66) as a
+// modular LLM-ability (v0.40.0, #67) — a THIRD region state, besides "owned by
+// one nation" and "no man's land": a war frontline that is in **no** nation's
+// `territory` and not in `unowned`, contested by two or more nations at war.
+//
+// Each turn the LLM may `open` a region as a contested frontline and/or
+// `resolve` an existing one. `open` requires the region to have a SOLE owner
+// that is at war with at least one of the parties, or to be no man's land (in
+// `unowned`) with two or more of the parties at war with each other; a region
+// with two or more owners, or whose owner is not at war with any party, cannot
+// be contested (dropped). On a successful open the key is removed from its
+// owner's `territory` (sole ownership is preserved — a contested key is in NO
+// territory) and from `unowned`, its `regionStats` entry is deleted, and a
+// `{ regionKey, parties }` entry (parties = resolved nation ids) is added to
+// `GameState.contested` (unique by `regionKey` — re-opening replaces it).
+// `resolve` removes the entry and releases the key to no man's land — UNLESS a
+// concurrent winning claim by one of the parties (allowed by the
+// territory-step guard in engine.ts) already re-owned it, in which case it
+// stays owned and its stats are kept.
+//
+// A still-contested key is NOT a valid normal-claim target: a plain `gain` on
+// it is dropped in the territory step (only a resolving party's claim
+// re-owns it). The layer NEVER moves a key into two territories (sole
+// ownership is sacrosanct), never touches borders directly (the key simply
+// leaves ownership), and is deterministic (no hidden randomness — the LLM
+// declares, the engine applies fixed rules).
+//
+// This is a DURABLE ability (unlike the turn-transient hybrid / disasters /
+// migration layers): it owns the `GameState.contested` field, and the user
+// payload carries the current contested list (only when non-empty).
+
+import { deriveNationStats } from '../../shared/protocol';
+import type { ContestedOps, ContestedRegion } from '../../shared/protocol';
+// The map-fill constants + tooltip label live in the shared protocol module
+// (like the sea-zone / no-man's-land constants); re-exported here so the
+// index / engine re-export surface is one consistent place.
+export {
+  CONTESTED_FILL,
+  CONTESTED_STROKE,
+  contestedTooltipLabel,
+} from '../../shared/protocol';
+import type { GameState } from '../../shared/types';
+import { atWar } from './apply-helpers';
+import { resolveNationRef, resolveRegionKey, str } from './shared';
+import type { Ability, AbilityCtx } from './types';
+
+/**
+ * (v0.44.0, #66) The SOLE owners of a region key in `next` (a key that is in no
+ * nation's `territory` yields `[]`; a corrupt 2+ owner key yields both). Pure.
+ */
+function currentOwners(next: GameState, key: string): string[] {
+  const owners: string[] = [];
+  for (const n of Object.values(next.nations)) {
+    if (n.territory.includes(key)) owners.push(n.id);
+  }
+  return owners;
+}
+
+/**
+ * (v0.44.0, #66) Resolve a region reference (a raw key or a human name) to a
+ * concrete region key: exact key first, then a unique case-insensitive name
+ * match. With no region-key manifest loaded (`validKeys` undefined) the raw
+ * string is accepted as the key (a name cannot be resolved without the
+ * manifest). Returns `null` when the reference is empty or unresolvable.
+ */
+function resolveKey(
+  ref: string,
+  validKeys?: ReadonlySet<string>,
+  nameOf?: (key: string) => string | undefined,
+): string | null {
+  const r = (ref ?? '').trim();
+  if (!r) return null;
+  if (!validKeys) return r; // no manifest: accept the raw key as-is
+  return resolveRegionKey(r, validKeys, nameOf ?? (() => undefined));
+}
+
+/**
+ * (v0.44.0, #66) Resolve a list of party references to distinct nation ids
+ * (id first, then a case-insensitive unique name), preserving first-appearance
+ * order. An unresolvable ref is dropped. Pure.
+ */
+function resolveParties(next: GameState, refs: string[]): string[] {
+  const out: string[] = [];
+  for (const ref of refs) {
+    const id = resolveNationRef(next, ref);
+    if (id && !out.includes(id)) out.push(id);
+  }
+  return out;
+}
+
+/**
+ * (v0.44.0, #66) Re-derive a nation's aggregate `stats` from its regions'
+ * per-region stats, with the same 0-region / no-entry guards as the engine's
+ * main recompute (a nation with no region, or none with a stats entry, keeps
+ * its directly-mutated `stats`). Used after a contested open strips a region
+ * from its owner. Never throws.
+ */
+function rederiveOwnerStats(
+  next: GameState,
+  ownerId: string,
+  geoOf?: (key: string) => { area: number; population: number } | undefined,
+): void {
+  const n = next.nations[ownerId];
+  if (!n) return;
+  if (n.territory.length > 0 && n.territory.some((k) => next.regionStats[k])) {
+    n.stats = deriveNationStats(n.territory, next.regionStats, geoOf);
+  }
+}
+
+/**
+ * (v0.44.0, #66) Validate the raw `contested` field of a turn into a safe
+ * {@link ContestedOps}. Defensive like the rest of the parser — never throws.
+ * `open`: each op needs a non-empty `regionKey` (capped at 120 chars) and
+ * TWO OR MORE non-empty `parties` refs (each capped at 200 chars); an op with
+ * a missing `regionKey` or fewer than two party refs is dropped. `resolve`:
+ * each entry is a non-empty region key (capped at 120 chars); empty / non-
+ * string entries are dropped. Both region keys and party refs are kept RAW
+ * here (like the hybrid / economy / industry refs) — whether a ref resolves to
+ * a real region / nation, and whether the war-linkage / ownership conditions
+ * hold, is checked at apply time (a ref that does not resolve, or a region that
+ * is not contestable, is dropped there). A missing / malformed top-level object
+ * yields `{ open: [], resolve: [] }`.
+ */
+export function validateContestedOps(raw: unknown): ContestedOps {
+  const out: ContestedOps = { open: [], resolve: [] };
+  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return out;
+  const o = raw as Record<string, unknown>;
+  if (Array.isArray(o.open)) {
+    for (const e of o.open) {
+      if (!e || typeof e !== 'object') continue;
+      const p = e as Record<string, unknown>;
+      const regionKey = str(p.regionKey, 120);
+      if (!regionKey) continue; // missing / empty region key: drop
+      if (!Array.isArray(p.parties)) continue; // missing / malformed parties: drop
+      const parties = p.parties
+        .map((x) => str(x, 200))
+        .filter((x): x is string => x !== null);
+      if (parties.length < 2) continue; // need at least two party refs
+      out.open.push({ regionKey, parties });
+    }
+  }
+  if (Array.isArray(o.resolve)) {
+    for (const e of o.resolve) {
+      const key = str(e, 120);
+      if (key) out.resolve.push(key);
+    }
+  }
+  return out;
+}
+
+/**
+ * (v0.44.0, #66) Apply the turn's contested-region ops to `next`, mutating in
+ * place and never throwing. Runs in the `ABILITIES` loop AFTER the territory
+ * step and the derived-stats recompute, and BEFORE markers / nationOps, so the
+ * owner / unowned / wars it inspects are all final for this turn.
+ *
+ *  (1) RESOLVE (first): each key in `resolve` that is currently contested is
+ *      removed from `next.contested` and released to no man's land (into
+ *      `unowned`, out of any territory, `regionStats` deleted) — UNLESS a
+ *      concurrent winning claim by one of the parties (the only claim the
+ *      territory step permits on a contested key) already re-owned it, in
+ *      which case it stays owned and keeps (or re-inits) its stats.
+ *  (2) OPEN: each op that resolves to a contestable region (a sole owner at
+ *      war with a party, or a no-man's-land region whose parties are at war
+ *      with each other) is moved out of ownership (the owner's territory /
+ *      `unowned`), its `regionStats` is deleted, and it is added to
+ *      `next.contested` (unique by `regionKey` — an open replaces a kept
+ *      entry for the same key). The stripped owner's derived stats are
+ *      re-derived.
+ *
+ * A contested key is never placed into two territories and is never left in
+ * `unowned` (the two states are mutually exclusive), so the sole-ownership
+ * invariant holds after every op.
+ */
+export function applyContested(next: GameState, ops: ContestedOps, ctx: AbilityCtx): void {
+  const validKeys = ctx.validRegionKeys;
+  const nameOf = ctx.regionNameOf;
+  const geoOf = ctx.geoOf;
+  const open = Array.isArray(ops?.open) ? ops.open : [];
+  const resolve = Array.isArray(ops?.resolve) ? ops.resolve : [];
+  const prevContested = Array.isArray(next.contested) ? next.contested : [];
+
+  // (1) RESOLVE first: rebuild the kept list, dropping resolved keys. A
+  // resolved key is released to no man's land unless a party re-owned it.
+  const resolveSet = new Set(resolve);
+  const kept: ContestedRegion[] = [];
+  for (const c of prevContested) {
+    if (!resolveSet.has(c.regionKey)) {
+      kept.push(c); // not resolved this turn: keep
+      continue;
+    }
+    const owners = currentOwners(next, c.regionKey);
+    if (owners.length === 1 && c.parties.includes(owners[0])) {
+      // A party re-owned it via a concurrent winning claim (the territory step
+      // allowed it): keep it owned, ensure it has stats (the claim re-inits an
+      // absent entry; the post-claim recompute already reflected the gain).
+      if (!next.regionStats[c.regionKey]) {
+        next.regionStats[c.regionKey] = { ...next.nations[owners[0]].stats };
+      }
+      continue; // stays owned — not re-added to `contested`
+    }
+    // Release to no man's land: out of any territory (defensive — a contested
+    // key is normally in none), into `unowned`, and its per-region stats leave.
+    for (const n of Object.values(next.nations)) {
+      const i = n.territory.indexOf(c.regionKey);
+      if (i !== -1) n.territory.splice(i, 1);
+    }
+    if (!next.unowned.includes(c.regionKey)) next.unowned.push(c.regionKey);
+    delete next.regionStats[c.regionKey];
+  }
+
+  // (2) OPEN: each op that resolves to a contestable region is moved out of
+  // ownership and added to the contested list (unique by region key).
+  const opened = new Map<string, string[]>(); // region key -> resolved party ids
+  for (const op of open) {
+    const key = resolveKey(op.regionKey, validKeys, nameOf);
+    if (!key) continue;
+    const parties = resolveParties(next, op.parties);
+    if (parties.length < 2) continue; // fewer than two distinct resolved parties
+
+    const owners = currentOwners(next, key);
+    let ok = false;
+    if (owners.length === 1) {
+      // Sole owner present: the owner must be at war with at least one party
+      // (the owner may itself be a party — atWar is false for a==b, so this
+      // checks the owner against the OTHER parties).
+      ok = parties.some((p) => atWar(next.wars, owners[0], p));
+    } else if (owners.length === 0 && next.unowned.includes(key)) {
+      // No owner + no man's land: two of the parties must be at war with
+      // each other.
+      for (let i = 0; i < parties.length && !ok; i++) {
+        for (let j = i + 1; j < parties.length; j++) {
+          if (atWar(next.wars, parties[i], parties[j])) {
+            ok = true;
+            break;
+          }
+        }
+      }
+    }
+    // Two or more owners (corrupt), an owner not at war with any party, or a
+    // not-in-unowned keyless region: never contestable (dropped).
+    if (!ok) continue;
+
+    if (owners.length === 1) {
+      const n = next.nations[owners[0]];
+      const i = n.territory.indexOf(key);
+      if (i !== -1) n.territory.splice(i, 1);
+      rederiveOwnerStats(next, owners[0], geoOf);
+    } else {
+      const i = next.unowned.indexOf(key);
+      if (i !== -1) next.unowned.splice(i, 1);
+    }
+    delete next.regionStats[key];
+    opened.set(key, parties);
+  }
+
+  // Rebuild `next.contested`: the kept (unresolved) entries plus the newly
+  // opened ones, unique by region key (an open replaces a kept entry for the
+  // same key; a resolve removed its key from `kept` above).
+  const final: ContestedRegion[] = [];
+  const seen = new Set<string>();
+  for (const c of kept) {
+    if (opened.has(c.regionKey)) continue; // replaced by a re-open this turn
+    if (seen.has(c.regionKey)) continue; // dedupe (should not happen, but safe)
+    seen.add(c.regionKey);
+    final.push(c);
+  }
+  for (const [key, parties] of opened) {
+    if (seen.has(key)) continue;
+    seen.add(key);
+    final.push({ regionKey: key, parties });
+  }
+  next.contested = final;
+}
+
+export const contested: Ability<'contested'> = {
+  field: 'contested',
+  default: () => ({ open: [], resolve: [] }),
+  validate: (raw) => validateContestedOps(raw),
+  apply: (state, data, ctx) => applyContested(state, data, ctx),
+  schemaLine: () =>
+    '  "contested": {"open":[{"regionKey":"<region key>","parties":["<nation 1>","<nation 2>"]}],"resolve":["<region key>"]},',
+  constraint: () =>
+    '- Contested regions ("contested") are WAR FRONTLINES: a region that no nation controls and that is not no man\'s land, contested by two or more nations at war. An "open" op ({"regionKey":"<key>","parties":["<a>","<b>"]}) makes a region a frontline — it leaves its owner\'s territory (or no-man\'s-land) and is contested: the region\'s sole owner must be at war with at least one of the parties, or (for a no-man\'s-land region) two of the parties must be at war with each other. A "resolve" op (["<key>"]) ends a frontline, releasing the region to no man\'s land — unless a party\'s concurrent claim re-owns it. A contested region is in NO nation\'s territory (never two) and is never no man\'s land while contested. The user message\'s "contested" field lists the current frontlines (region key + party names). Propose at most 1-2 contested-region changes per turn and narrate each one in "events" (a "military" event).',
+  isMeaningful: (data) => data.open.length > 0 || data.resolve.length > 0,
+  stateFields: ['contested'],
+  stub: () => ({ open: [], resolve: [] }),
+  // The user payload carries the current contested frontlines (region key +
+  // party NAMES, resolved from the stored ids) — but only when non-empty (a
+  // fresh / no-frontline world contributes nothing, like the turn-transient
+  // layers).
+  payload: (ctx) => {
+    if (!ctx.contested || ctx.contested.length === 0) return {};
+    return {
+      contested: ctx.contested.map((c) => ({
+        regionKey: c.regionKey,
+        parties: c.parties.map((id) => ctx.state.nations[id]?.name ?? id),
+      })),
+    };
+  },
+};

server/abilities/disasters.test.ts

@@ -72,6 +72,8 @@ function mkState(
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
 }
 

server/abilities/goldens/system-no-tool.txt

@@ -42,6 +42,7 @@ Respond with ONLY a valid JSON object of exactly this shape. No prose, no commen
   "disasters": {"events":[{"type":"<earthquake|flood|volcanic|wildfire|famine|plague|epidemic>","target":"<nation id or name, or region key>","severity":"<minor|moderate|severe>","detail":"<short detail>"}]},
   "migration": {"ops":[{"kind":"<migration|refugees|diaspora|exodus>","from":"<nation id or name>","to":"<nation id or name>","scale":"<small|moderate|large>","detail":"<short detail>"}]},
   "sea": {"control":[{"zone":"<seaZoneId>","by":"<nation id or name>"}]},
+  "contested": {"open":[{"regionKey":"<region key>","parties":["<nation 1>","<nation 2>"]}],"resolve":["<region key>"]},
   "markers": {"add":[{"type":"<city|factory|army|port|capital|fleet|rocket|gathering>","name":"<short name>","regionKey":"<region key>"}],"remove":["<marker id>"]}
 }
 
@@ -70,6 +71,7 @@ HARD CONSTRAINTS
 - Disasters & pandemics ("disasters.events") are natural and man-made catastrophes — earthquakes, floods, volcanic eruptions, wildfires, famines, plagues, and epidemics — that hit a nation or a single region this turn. Each event names a "target" (a nation id / name, or a region key that hits that region's SOLE owner — a region with 0 or 2+ owners can't be hit) and a "severity" (minor / moderate / severe); the engine applies a small, DETERMINISTIC stat dip from the (type, severity) table (a severe plague is the hardest hit; none of them touch population, and none move borders — sole ownership is untouched). There is NO memory of past disasters (the layer is turn-transient): a plague or epidemic that persists is simply RE-DECLARED each turn it continues, with a fresh "severity". Propose at most 1-2 events per turn and narrate each one in "events" (a "disaster" event).
 - Migration & refugees ("migration.ops") are people moving between nations this turn: a "kind" ("migration", "refugees", "diaspora", or "exodus"), a "from" (the source nation — id or name), a "to" (the destination nation — required for every kind except "exodus", which has no destination), and a "scale" (small / moderate / large). The engine applies a DETERMINISTIC effect (no hidden randomness): the source LOSES a small amount of population and economy, the destination GAINS a small amount of population and economy (a "large" influx additionally strains the destination's stability by 2), and the from↔to relation moves one step toward the positive end of the ally/neutral/rival/hostile ladder — capped at "ally" for "refugees" (hosting refugees builds the strongest goodwill), capped at "neutral" for "migration"/"diaspora" (milder ties), and not at all for "exodus"; the nudge never creates or escalates a "war" (a warring pair is left untouched). The layer is turn-transient (no memory): a continuing flow is simply RE-DECLARED each turn it persists. It never moves borders — sole ownership is untouched. Propose at most 1-2 per turn and narrate each one in "events" (a "social" or "diplomatic" event).
 - Sea control ("sea") is the naval layer, fully parallel to but INDEPENDENT of land: each of the 12 fixed sea zones — "north-atlantic" (North Atlantic), "south-atlantic" (South Atlantic), "pacific" (Pacific Ocean), "indian" (Indian Ocean), "mediterranean" (Mediterranean Sea), "north-sea" (North Sea), "baltic" (Baltic Sea), "arctic" (Arctic Ocean), "black-sea" (Black Sea), "gulf-mexico" (Gulf of Mexico), "red-sea" (Red Sea), "sargasso" (Sargasso Sea) — is under the SOLE control of at most one nation. A control op ({"zone":"<id>","by":"<nation>"}) sets or replaces that zone's controller (the user message's "seaZones" field lists who controls what now); if two or more ops this turn claim the SAME zone for DIFFERENT nations, the zone is CONTESTED and the higher current "military" wins (a tie goes to the earlier-listed op). Every committed turn each zone's controller earns a small deterministic +1 military and +1 economy. Sea control NEVER moves land (no territory changes) — it is a parallel track. Propose at most 1-2 claims per turn and narrate each one in "events" (a "military" or "diplomatic" event).
+- Contested regions ("contested") are WAR FRONTLINES: a region that no nation controls and that is not no man's land, contested by two or more nations at war. An "open" op ({"regionKey":"<key>","parties":["<a>","<b>"]}) makes a region a frontline — it leaves its owner's territory (or no-man's-land) and is contested: the region's sole owner must be at war with at least one of the parties, or (for a no-man's-land region) two of the parties must be at war with each other. A "resolve" op (["<key>"]) ends a frontline, releasing the region to no man's land — unless a party's concurrent claim re-owns it. A contested region is in NO nation's territory (never two) and is never no man's land while contested. The user message's "contested" field lists the current frontlines (region key + party names). Propose at most 1-2 contested-region changes per turn and narrate each one in "events" (a "military" event).
 - Prefer 1-4 events per turn; keep each text 1-3 sentences.
 - Keep your internal reasoning brief (a few sentences) and go straight to the JSON result; do not over-deliberate or re-derive facts already present in the state.
 - Keep every stat value between 0 and 100.

server/abilities/goldens/system-tool.txt

@@ -42,6 +42,7 @@ You have a getNeighbours tool: given region keys it returns the region keys that
   "disasters": {"events":[{"type":"<earthquake|flood|volcanic|wildfire|famine|plague|epidemic>","target":"<nation id or name, or region key>","severity":"<minor|moderate|severe>","detail":"<short detail>"}]},
   "migration": {"ops":[{"kind":"<migration|refugees|diaspora|exodus>","from":"<nation id or name>","to":"<nation id or name>","scale":"<small|moderate|large>","detail":"<short detail>"}]},
   "sea": {"control":[{"zone":"<seaZoneId>","by":"<nation id or name>"}]},
+  "contested": {"open":[{"regionKey":"<region key>","parties":["<nation 1>","<nation 2>"]}],"resolve":["<region key>"]},
   "markers": {"add":[{"type":"<city|factory|army|port|capital|fleet|rocket|gathering>","name":"<short name>","regionKey":"<region key>"}],"remove":["<marker id>"]}
 }
 
@@ -70,6 +71,7 @@ HARD CONSTRAINTS
 - Disasters & pandemics ("disasters.events") are natural and man-made catastrophes — earthquakes, floods, volcanic eruptions, wildfires, famines, plagues, and epidemics — that hit a nation or a single region this turn. Each event names a "target" (a nation id / name, or a region key that hits that region's SOLE owner — a region with 0 or 2+ owners can't be hit) and a "severity" (minor / moderate / severe); the engine applies a small, DETERMINISTIC stat dip from the (type, severity) table (a severe plague is the hardest hit; none of them touch population, and none move borders — sole ownership is untouched). There is NO memory of past disasters (the layer is turn-transient): a plague or epidemic that persists is simply RE-DECLARED each turn it continues, with a fresh "severity". Propose at most 1-2 events per turn and narrate each one in "events" (a "disaster" event).
 - Migration & refugees ("migration.ops") are people moving between nations this turn: a "kind" ("migration", "refugees", "diaspora", or "exodus"), a "from" (the source nation — id or name), a "to" (the destination nation — required for every kind except "exodus", which has no destination), and a "scale" (small / moderate / large). The engine applies a DETERMINISTIC effect (no hidden randomness): the source LOSES a small amount of population and economy, the destination GAINS a small amount of population and economy (a "large" influx additionally strains the destination's stability by 2), and the from↔to relation moves one step toward the positive end of the ally/neutral/rival/hostile ladder — capped at "ally" for "refugees" (hosting refugees builds the strongest goodwill), capped at "neutral" for "migration"/"diaspora" (milder ties), and not at all for "exodus"; the nudge never creates or escalates a "war" (a warring pair is left untouched). The layer is turn-transient (no memory): a continuing flow is simply RE-DECLARED each turn it persists. It never moves borders — sole ownership is untouched. Propose at most 1-2 per turn and narrate each one in "events" (a "social" or "diplomatic" event).
 - Sea control ("sea") is the naval layer, fully parallel to but INDEPENDENT of land: each of the 12 fixed sea zones — "north-atlantic" (North Atlantic), "south-atlantic" (South Atlantic), "pacific" (Pacific Ocean), "indian" (Indian Ocean), "mediterranean" (Mediterranean Sea), "north-sea" (North Sea), "baltic" (Baltic Sea), "arctic" (Arctic Ocean), "black-sea" (Black Sea), "gulf-mexico" (Gulf of Mexico), "red-sea" (Red Sea), "sargasso" (Sargasso Sea) — is under the SOLE control of at most one nation. A control op ({"zone":"<id>","by":"<nation>"}) sets or replaces that zone's controller (the user message's "seaZones" field lists who controls what now); if two or more ops this turn claim the SAME zone for DIFFERENT nations, the zone is CONTESTED and the higher current "military" wins (a tie goes to the earlier-listed op). Every committed turn each zone's controller earns a small deterministic +1 military and +1 economy. Sea control NEVER moves land (no territory changes) — it is a parallel track. Propose at most 1-2 claims per turn and narrate each one in "events" (a "military" or "diplomatic" event).
+- Contested regions ("contested") are WAR FRONTLINES: a region that no nation controls and that is not no man's land, contested by two or more nations at war. An "open" op ({"regionKey":"<key>","parties":["<a>","<b>"]}) makes a region a frontline — it leaves its owner's territory (or no-man's-land) and is contested: the region's sole owner must be at war with at least one of the parties, or (for a no-man's-land region) two of the parties must be at war with each other. A "resolve" op (["<key>"]) ends a frontline, releasing the region to no man's land — unless a party's concurrent claim re-owns it. A contested region is in NO nation's territory (never two) and is never no man's land while contested. The user message's "contested" field lists the current frontlines (region key + party names). Propose at most 1-2 contested-region changes per turn and narrate each one in "events" (a "military" event).
 - Prefer 1-4 events per turn; keep each text 1-3 sentences.
 - Keep your internal reasoning brief (a few sentences) and go straight to the JSON result; do not over-deliberate or re-derive facts already present in the state.
 - Keep every stat value between 0 and 100.

server/abilities/goldens/user.txt

@@ -206,5 +206,14 @@
       "type": "industry"
     }
   ],
-  "seaZones": []
+  "seaZones": [],
+  "contested": [
+    {
+      "regionKey": "b-r1",
+      "parties": [
+        "Alpha",
+        "Bravo"
+      ]
+    }
+  ]
 }

server/abilities/index.ts

@@ -1,8 +1,8 @@
 // The ordered LLM-ability registry.
 //
-// `ABILITIES` is the single source of truth for the 11 per-feature LLM abilities.
+// `ABILITIES` is the single source of truth for the 12 per-feature LLM abilities.
 // The engine iterates it in this order:
-//   takeovers → wars → hybrid → economy → industry → nuclear → leaders → ideology → disasters → migration → sea
+//   takeovers → wars → hybrid → economy → industry → nuclear → leaders → ideology → disasters → migration → sea → contested
 // for (a) the system-prompt schema lines + constraint bullets, (b) the per-ability
 // validate calls inside validateTurnResult, (c) the payload fields in buildUserPrompt,
 // (d) the ordered apply block inside applyTurnResult, (e) the isMeaningful check,
@@ -25,10 +25,11 @@ import { ideology } from './ideology';
 import { disasters } from './disasters';
 import { migration } from './migration';
 import { sea } from './sea';
+import { contested } from './contested';
 import type { Ability, AbilityField } from './types';
 
 /**
- * The 11 per-feature LLM abilities in their canonical apply order.
+ * The 12 per-feature LLM abilities in their canonical apply order.
  * The order matters: it determines the order of the schema lines in the
  * system prompt, the order of the validate calls, the order of the apply
  * steps, and the order of the payload fields in the user prompt. New
@@ -47,6 +48,7 @@ export const ABILITIES: readonly Ability<AbilityField>[] = [
   disasters,
   migration,
   sea,
+  contested,
 ];
 
 // ── type re-exports ────────────────────────────────────────────────────────────
@@ -173,3 +175,13 @@ export {
   isSeaZoneId,
   seaZoneName,
 } from './sea';
+
+// ── contested (frontlines) ───────────────────────────────────────────────────
+
+export {
+  validateContestedOps,
+  applyContested,
+  CONTESTED_FILL,
+  CONTESTED_STROKE,
+  contestedTooltipLabel,
+} from './contested';

server/abilities/migration.test.ts

@@ -84,6 +84,8 @@ function mkState(
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
 }
 

server/abilities/registry.test.ts

@@ -12,7 +12,7 @@
 //      by the disasters feature (its payload is always empty).
 //
 //   2. REGISTRY CONTRACT — the ABILITIES registry is the canonical ordered
-//      list of the 11 abilities; each ability's default() equals the canonical
+//      list of the 12 abilities; each ability's default() equals the canonical
 //      TurnResult default for its field, is a FRESH value (never a shared
 //      reference), its default is not "meaningful" while a populated value is,
 //      and the registry composes (a hypothetical extra ability can be appended
@@ -76,6 +76,12 @@ import {
   SEA_ZONE_IDS,
   isSeaZoneId,
   seaZoneName,
+  // contested (v0.44.0, #66)
+  validateContestedOps,
+  applyContested,
+  CONTESTED_FILL,
+  CONTESTED_STROKE,
+  contestedTooltipLabel,
 } from '../engine';
 import { createPresetStore } from '../presets';
 import { ABILITIES } from './index';
@@ -92,7 +98,7 @@ import type {
   SeaZoneClaim,
   TradeAgreement,
 } from '../../shared/types';
-import type { MarkerInfo, TurnResult, WarInfo } from '../../shared/protocol';
+import type { ContestedRegion, MarkerInfo, TurnResult, WarInfo } from '../../shared/protocol';
 
 const here = path.dirname(fileURLToPath(import.meta.url));
 const goldensDir = path.join(here, 'goldens');
@@ -165,6 +171,8 @@ const state: GameState = {
   industry: [],
   // (v0.43.0, #65) no sea-zone control on a fresh state.
   seaZones: [],
+  // (v0.44.0, #66) no contested regions on a fresh state.
+  contested: [],
 };
 
 // --- buildUserPrompt arguments: every optional branch exercised. ---
@@ -202,6 +210,10 @@ const nationResources: Record<string, RegionResources> = {
 const industryProjects: IndustryProject[] = [{ regionKey: 'a-r1', type: 'industry' }];
 const nuclear: Record<string, boolean> = { a1: true, b2: false, c3: false };
 const seaZones: SeaZoneClaim[] = [];
+// (v0.44.0, #66) a non-empty contested sample so the golden's user payload
+// includes the `contested` key (region key + party NAMES, resolved from the
+// state's nations). `b-r1` is owned by b2; the parties are a1 + b2.
+const contested: ContestedRegion[] = [{ regionKey: 'b-r1', parties: ['a1', 'b2'] }];
 
 /**
  * Assert the current prompt output is byte-identical to the committed golden —
@@ -241,6 +253,7 @@ function fullDefaultTurn(): TurnResult {
     disasters: { events: [] },
     migration: { ops: [] },
     sea: { control: [] },
+    contested: { open: [], resolve: [] },
     markers: { add: [], remove: [] },
   };
 }
@@ -270,11 +283,13 @@ function meaningfulFor(field: AbilityField): TurnResult[AbilityField] {
       return { ops: [{ kind: 'migration', from: 'a1', to: 'b2', scale: 'small' }] };
     case 'sea':
       return { control: [{ zone: 'pacific', by: 'a1' }] };
+    case 'contested':
+      return { open: [{ regionKey: 'b-r1', parties: ['a1', 'b2'] }], resolve: [] };
   }
 }
 
 describe('ABILITIES registry (v0.40.0, #67)', () => {
-  it('is the canonical 11-ability order (takeovers → sea)', () => {
+  it('is the canonical 12-ability order (takeovers → contested)', () => {
     expect(ABILITIES.map((a) => a.field)).toEqual([
       'takeovers',
       'wars',
@@ -287,13 +302,14 @@ describe('ABILITIES registry (v0.40.0, #67)', () => {
       'disasters',
       'migration',
       'sea',
+      'contested',
     ]);
   });
 
-  it('lists 11 distinct fields, each a key of TurnResult', () => {
+  it('lists 12 distinct fields, each a key of TurnResult', () => {
     const fields = ABILITIES.map((a) => a.field);
-    expect(fields).toHaveLength(11);
+    expect(fields).toHaveLength(12);
-    expect(new Set(fields).size).toBe(11);
+    expect(new Set(fields).size).toBe(12);
     const all = fullDefaultTurn();
     for (const f of fields) expect(f in all).toBe(true);
   });
@@ -324,6 +340,7 @@ describe('ABILITIES registry (v0.40.0, #67)', () => {
         industryProjects,
         nuclear,
         seaZones,
+        contested,
       ),
     );
   });
@@ -353,13 +370,13 @@ describe('ABILITIES registry (v0.40.0, #67)', () => {
   it('declares exactly the durable GameState fields the db migration must default', () => {
     const owned: string[] = [];
     for (const a of ABILITIES) if (a.stateFields) owned.push(...a.stateFields);
-    expect([...owned].sort()).toEqual(['embargoes', 'industry', 'seaZones', 'trades', 'wars']);
+    expect([...owned].sort()).toEqual(['contested', 'embargoes', 'industry', 'seaZones', 'trades', 'wars']);
   });
 
   it('composes: a hypothetical extra ability can be appended and every uniform loop still runs', () => {
     // The registry is a plain ordered array the engine iterates uniformly. A
     // structural (field-name-agnostic) loop over the abilities — schema line,
-    // constraint bullet — must keep working when an 11th ability is appended.
+    // constraint bullet — must keep working when a 12th ability is appended.
     // This documents the extension point without widening the closed
     // AbilityField union.
     interface Loopable {
@@ -378,9 +395,9 @@ describe('ABILITIES registry (v0.40.0, #67)', () => {
       'custom',
     ]);
     // every uniform loop runs over all N abilities, the appended one included:
-    expect(extended.map((a) => a.schemaLine())).toHaveLength(12);
+    expect(extended.map((a) => a.schemaLine())).toHaveLength(13);
-    expect(extended.map((a) => a.constraint())).toHaveLength(12);
+    expect(extended.map((a) => a.constraint())).toHaveLength(13);
-    expect(extended[11].schemaLine()).toBe('  "custom": [],');
+    expect(extended[12].schemaLine()).toBe('  "custom": [],');
   });
 
   it('the engine still re-exports every name its callers import from it', () => {
@@ -439,6 +456,12 @@ describe('ABILITIES registry (v0.40.0, #67)', () => {
       SEA_ZONE_IDS,
       isSeaZoneId,
       seaZoneName,
+      // contested (v0.44.0, #66)
+      validateContestedOps,
+      applyContested,
+      CONTESTED_FILL,
+      CONTESTED_STROKE,
+      contestedTooltipLabel,
     };
     for (const [name, value] of Object.entries(reexported)) {
       expect(value, `engine should re-export ${name}`).toBeDefined();

server/abilities/sea.test.ts

@@ -85,6 +85,8 @@ function mkState(
     embargoes: [],
     industry: [],
     seaZones,
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
 }
 

server/abilities/types.ts

@@ -15,14 +15,14 @@ import type {
   SeaZoneClaim,
   TradeAgreement,
 } from '../../shared/types';
-import type { MarkerInfo, TurnResult, WarInfo } from '../../shared/protocol';
+import type { ContestedRegion, MarkerInfo, TurnResult, WarInfo } from '../../shared/protocol';
 
 /**
- * The 11 per-feature LLM abilities a turn can exercise, by the `TurnResult`
+ * The 12 per-feature LLM abilities a turn can exercise, by the `TurnResult`
  * field each one owns. This is the closed universe the ordered `ABILITIES`
  * registry (./index.ts) is built from: a turn's world changes are exactly the
  * core engine effects (events / stats / territory / no-man's-land / nation-ops
- * / markers) plus, in order, these eleven abilities.
+ * / markers) plus, in order, these twelve abilities.
  */
 export type AbilityField =
   | 'takeovers'
@@ -35,7 +35,8 @@ export type AbilityField =
   | 'ideology'
   | 'disasters'
   | 'migration'
-  | 'sea';
+  | 'sea'
+  | 'contested';
 
 /**
  * Everything a single ability's `apply` may need from the surrounding turn.
@@ -92,6 +93,7 @@ export interface UserPromptCtx {
   readonly nationResources?: Record<string, RegionResources>;
   readonly industryProjects?: IndustryProject[];
   readonly seaZones?: SeaZoneClaim[];
+  readonly contested?: ContestedRegion[];
 }
 
 /**

server/db.test.ts

@@ -40,6 +40,8 @@ function makeState(id: string): GameState {
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
 }
 
@@ -257,6 +259,17 @@ describe('openDb', () => {
     db.close();
   });
 
+  it('(v0.44.0 #66) a legacy row saved before the contested field existed loads with it defaulted to []', () => {
+    const db = openDb(':memory:');
+    const legacy = makeState('legacy');
+    delete (legacy as { contested?: unknown[] }).contested; // a pre-v0.44 save (field absent)
+    db.save(legacy);
+    const loaded = db.load('legacy');
+    expect(loaded).not.toBeNull();
+    expect(loaded!.contested).toEqual([]);
+    db.close();
+  });
+
   it('delete removes a game by id and reports absence otherwise', () => {
     const db = openDb(':memory:');
     db.save(makeState('a'));

server/engine.test.ts

@@ -135,6 +135,8 @@ function baseState(): GameState {
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
 }
 
@@ -572,7 +574,7 @@ describe('validateNationOps (v0.23 #16 P4a)', () => {
       relations: [],
       territoryChanges: [],
       unowned: [],
-      nationOps: [{ kind: 'rename', nationRef: 'France', to: 'French Republic' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [{ kind: 'rename', nationRef: 'France', to: 'French Republic' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     });
     expect(withOps).not.toBeNull();
     expect(withOps!.nationOps).toEqual([{ kind: 'rename', nationRef: 'France', to: 'French Republic' }]);
@@ -594,7 +596,7 @@ describe('applyTurnResult (nation-op proposals, v0.23 #16 P4a)', () => {
       relations: [],
       territoryChanges: [],
       unowned: [],
-      nationOps: [{ kind: 'rename', nationRef: 'de', to: 'Reich' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [{ kind: 'rename', nationRef: 'de', to: 'Reich' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     });
     expect(next.nations.de.name).toBe('DE'); // still the old name
     expect(next.pendingNationOps).toEqual([{ kind: 'rename', nationRef: 'de', to: 'Reich' }]);
@@ -615,7 +617,7 @@ describe('applyTurnResult (nation-op proposals, v0.23 #16 P4a)', () => {
       relations: [],
       territoryChanges: [],
       unowned: [],
-      nationOps: [{ kind: 'rename', nationRef: 'us', to: 'USA' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] }, // new proposal this turn
+      nationOps: [{ kind: 'rename', nationRef: 'us', to: 'USA' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] }, // new proposal this turn
     });
     expect(next.pendingNationOps).toEqual([
       { kind: 'rename', nationRef: 'de', to: 'Reich' }, // the old one survived
@@ -634,7 +636,7 @@ describe('applyTurnResult (nation-op proposals, v0.23 #16 P4a)', () => {
       relations: [],
       territoryChanges: [],
       unowned: [],
-      nationOps: [{ kind: 'rename', nationRef: 'de', to: 'Reich' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [{ kind: 'rename', nationRef: 'de', to: 'Reich' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     });
     expect(next.pendingNationOps).toEqual([{ kind: 'rename', nationRef: 'de', to: 'Reich' }]);
   });
@@ -1091,7 +1093,7 @@ describe('applyTurnResult', () => {
       relations: [],
       territoryChanges: [],
       unowned: [],
-      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     applyTurnResult(state, result);
     expect(JSON.stringify(state)).toBe(snapshot);
@@ -1108,7 +1110,7 @@ describe('applyTurnResult', () => {
       relations: [],
       territoryChanges: [],
       unowned: [],
-      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     expect(next.pending).toEqual([]);
@@ -1131,7 +1133,7 @@ describe('applyTurnResult', () => {
       // is not a real key at all. Both are proposed as a gain by DE.
       territoryChanges: [{ nation: 'de', gain: ['wales-bbbb', 'not-a-region-xyz'], lose: [] }],
       unowned: [],
-      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result, new Set(['wales-bbbb']));
     // the valid key was gained (taken from its sole previous owner); the bogus one was ignored
@@ -1157,7 +1159,7 @@ describe('applyTurnResult', () => {
       // released (not in state.unowned), so it does not enter GameState.unowned.
       territoryChanges: [{ nation: 'de', gain: ['POL', 'wales-bbbb'], lose: [] }],
       unowned: [],
-      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result); // no validKeys -> nothing filtered
     expect(next.nations.de.territory).toContain('wales-bbbb');
@@ -1175,7 +1177,7 @@ describe('applyTurnResult (sole-ownership invariants, v0.21 #16 P2)', () => {
     regionChanges: [],
     relations: [],
     unowned: [],
-    nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+    nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
   };
 
   it('a double claim (two different gainers, one key) is rejected: the key stays with its original owner', () => {
@@ -1265,7 +1267,7 @@ describe('applyTurnResult (no man\'s land, v0.22 #16 P3)', () => {
     relations: [],
     territoryChanges: [],
     unowned: [],
-    nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+    nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
   };
 
   it('a release removes the key from its sole owner and marks it in GameState.unowned', () => {
@@ -1380,7 +1382,7 @@ describe('applyTurnResult (no man\'s land, v0.22 #16 P3)', () => {
 
   it('a lone release is meaningful (it survives the retry/nudge path)', () => {
     expect(
-      isMeaningful({ date: 'x', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [], unowned: ['GBR'], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] } }),
+      isMeaningful({ date: 'x', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [], unowned: ['GBR'], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] } }),
     ).toBe(true);
   });
 
@@ -1687,9 +1689,9 @@ describe('buildSystemPrompt (tool mode, v0.21 #16 P2)', () => {
 
 describe('isMeaningful', () => {
   it('is true with an event, false when everything is empty', () => {
-    expect(isMeaningful({ date: 'x', events: [{ nation: 'uk', type: 'military', title: 't', text: 'b', outcome: 'neutral' }], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [], unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] } })).toBe(true);
+    expect(isMeaningful({ date: 'x', events: [{ nation: 'uk', type: 'military', title: 't', text: 'b', outcome: 'neutral' }], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [], unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] } })).toBe(true);
-    expect(isMeaningful({ date: 'x', events: [], stateChanges: [{ nation: 'uk', stat: 'military', op: 'set', value: 5 }], regionChanges: [], relations: [], territoryChanges: [], unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] } })).toBe(true);
+    expect(isMeaningful({ date: 'x', events: [], stateChanges: [{ nation: 'uk', stat: 'military', op: 'set', value: 5 }], regionChanges: [], relations: [], territoryChanges: [], unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] } })).toBe(true);
-    expect(isMeaningful({ date: 'x', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [], unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] } })).toBe(false);
+    expect(isMeaningful({ date: 'x', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [], unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] } })).toBe(false);
   });
 
   it('(v0.23 #16 P4a) a turn that only proposes a nation-op is meaningful (it survives the retry/nudge path)', () => {
@@ -1702,7 +1704,7 @@ describe('isMeaningful', () => {
         relations: [],
         territoryChanges: [],
         unowned: [],
-        nationOps: [{ kind: 'rename', nationRef: 'de', to: 'Reich' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+        nationOps: [{ kind: 'rename', nationRef: 'de', to: 'Reich' }], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
       }),
     ).toBe(true);
   });
@@ -1723,7 +1725,7 @@ describe('isMeaningful', () => {
         hybrid: { ops: [] },
         economy: { trade: [], embargo: [] }, industry: { projects: [] },
         nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [{ type: 'city', name: 'Lyon', regionKey: 'rhone-rhne' }], remove: [] },
+        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [{ type: 'city', name: 'Lyon', regionKey: 'rhone-rhne' }], remove: [] },
       }),
     ).toBe(true);
   });
@@ -1744,7 +1746,7 @@ describe('isMeaningful', () => {
         hybrid: { ops: [] },
         economy: { trade: [], embargo: [] }, industry: { projects: [] },
         nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
       }),
     ).toBe(true);
   });
@@ -1767,7 +1769,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     expect(next.nations.de.name).toBe('The Reich');
@@ -1800,7 +1802,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     expect(next.playerNationId).toBe('uk'); // player still leads it
@@ -1824,7 +1826,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     // no nation was renamed
@@ -1851,7 +1853,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     // neither was renamed (ambiguous)
@@ -1877,7 +1879,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     });
     expect(validated!.takeovers).toEqual([]);
     const next = applyTurnResult(state, validated!);
@@ -1903,7 +1905,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     expect(next.nations.uk.name).toBe('The Commonwealth');
@@ -1927,7 +1929,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     expect(next.version).toBe(2); // exactly one bump for the whole turn
@@ -1949,7 +1951,7 @@ describe('takeovers (regime change, v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     };
     const next = applyTurnResult(state, result);
     expect(next.nations.de.name).toBe('The Reich');
@@ -1983,7 +1985,7 @@ describe('markers (point placement, v0.27 #44)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [mk('city', 'Strasbourg', 'moselle-rygy')], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [mk('city', 'Strasbourg', 'moselle-rygy')], remove: [] },
     };
     const next = applyTurnResult(state, result, undefined, centroidOf);
     expect(next.markers).toHaveLength(1);
@@ -2007,13 +2009,13 @@ describe('markers (point placement, v0.27 #44)', () => {
     const add = [mk('city', 'Strasbourg', 'moselle-rygy')];
     const first = applyTurnResult(state, {
       date: '1939-09-03', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [],
-      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add, remove: [] },
+      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add, remove: [] },
     }, undefined, centroidOf);
     expect(first.markers).toHaveLength(1);
     // a second turn proposes the exact same marker again
     const second = applyTurnResult(first, {
       date: '1939-09-05', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [],
-      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add, remove: [] },
+      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add, remove: [] },
     }, undefined, centroidOf);
     expect(second.markers).toHaveLength(1);
     expect(second.markers[0].id).toBe(first.markers[0].id); // stable id, no second copy
@@ -2040,7 +2042,7 @@ describe('markers (point placement, v0.27 #44)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: {
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: {
         add: [
           { type: 'city', name: 'Good', regionKey: 'moselle-rygy' }, // valid + centroid → kept
           { type: 'city', name: 'NoCent', regionKey: 'other-key' }, // in validKeys, no centroid → dropped
@@ -2087,7 +2089,7 @@ describe('markers (point placement, v0.27 #44)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: {
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: {
         add: [
           { type: 'city', name: 'NewA', regionKey: 'new-a' },
           { type: 'city', name: 'NewB', regionKey: 'new-b' },
@@ -2112,7 +2114,7 @@ describe('markers (point placement, v0.27 #44)', () => {
     ];
     const next = applyTurnResult(state, {
       date: '1939-09-03', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [],
-      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [idA, 'zzzz-not-there'] },
+      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [idA, 'zzzz-not-there'] },
     }, undefined, centroidOf);
     expect(next.markers).toHaveLength(1);
     expect(next.markers[0].id).toBe(idB); // only A removed; the bogus id was a no-op
@@ -2128,14 +2130,14 @@ describe('markers (point placement, v0.27 #44)', () => {
     // 1) uk releases the region → the marker becomes ownerless
     const released = applyTurnResult(state, {
       date: '1939-09-03', events: [], stateChanges: [], regionChanges: [], relations: [], territoryChanges: [],
-      unowned: ['moselle-rygy'], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      unowned: ['moselle-rygy'], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     }, undefined, centroidOf);
     expect(released.markers[0].ownerNationId).toBeNull();
     // 2) de re-claims the region → the marker's owner follows to de
     const reclaimed = applyTurnResult(released, {
       date: '1939-09-05', events: [], stateChanges: [], regionChanges: [], relations: [],
       territoryChanges: [{ nation: 'de', gain: ['moselle-rygy'], lose: [] }],
-      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      unowned: [], nationOps: [], takeovers: [], wars: { declare: [], end: [] }, hybrid: { ops: [] }, economy: { trade: [], embargo: [] }, industry: { projects: [] }, nuclear: { arm: [], strikes: [] }, leaders: { changes: [] }, ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     }, undefined, centroidOf);
     expect(reclaimed.markers[0].ownerNationId).toBe('de');
   });
@@ -2205,7 +2207,7 @@ describe('markers (point placement, v0.27 #44)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [{ type: 'city', name: 'Strasbourg', regionKey: 'moselle-rygy' }], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [{ type: 'city', name: 'Strasbourg', regionKey: 'moselle-rygy' }], remove: [] },
     });
     const { state } = await runTurn({
       llm: fakeLlm([result]),
@@ -2282,6 +2284,8 @@ function mkTurnState(
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
 }
 
@@ -2306,6 +2310,7 @@ function mkTurnResult(partial: Partial<TurnResult>): TurnResult {
     disasters: partial.disasters ?? { events: [] },
     migration: partial.migration ?? { ops: [] },
     sea: partial.sea ?? { control: [] },
+    contested: partial.contested ?? { open: [], resolve: [] },
     markers: partial.markers ?? { add: [], remove: [] },
   };
 }
@@ -3031,7 +3036,7 @@ describe('validateTakeovers (v0.32.0 #54)', () => {
       hybrid: { ops: [] },
       economy: { trade: [], embargo: [] }, industry: { projects: [] },
       nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+      ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
     });
     expect(withTakeovers).not.toBeNull();
     // the valid one survives, the empty-name one is dropped
@@ -3419,7 +3424,7 @@ describe('isMeaningful — wars (v0.33.0 #56)', () => {
         hybrid: { ops: [] },
         economy: { trade: [], embargo: [] }, industry: { projects: [] },
         nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
       }),
     ).toBe(true);
   });
@@ -3440,7 +3445,7 @@ describe('isMeaningful — wars (v0.33.0 #56)', () => {
         hybrid: { ops: [] },
         economy: { trade: [], embargo: [] }, industry: { projects: [] },
         nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
       }),
     ).toBe(true);
   });
@@ -3461,7 +3466,7 @@ describe('isMeaningful — wars (v0.33.0 #56)', () => {
         hybrid: { ops: [] },
         economy: { trade: [], embargo: [] }, industry: { projects: [] },
         nuclear: { arm: [], strikes: [] }, leaders: { changes: [] },
-        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, markers: { add: [], remove: [] },
+        ideology: { changes: [] }, disasters: { events: [] }, migration: { ops: [] }, sea: { control: [] }, contested: { open: [], resolve: [] }, markers: { add: [], remove: [] },
       }),
     ).toBe(false);
   });

server/engine.ts

@@ -35,6 +35,7 @@ import {
   markerId,
   MAX_MARKERS,
   nationForPrompt,
+  type ContestedRegion,
   type MarkerInfo,
   type MarkerSpec,
   type NationOp,
@@ -113,6 +114,11 @@ export {
   SEA_ZONE_IDS,
   isSeaZoneId,
   seaZoneName,
+  validateContestedOps,
+  applyContested,
+  CONTESTED_FILL,
+  CONTESTED_STROKE,
+  contestedTooltipLabel,
 } from './abilities';
 
 // --- The LLM's getNeighbours tool (v0.21, #16 P2: contiguous region transfers) ---
@@ -393,6 +399,14 @@ export function buildUserPrompt(
    * `TurnResult.sea`. Omitted entirely when undefined.
    */
   seaZones?: SeaZoneClaim[],
+  /**
+   * (v0.44.0, #66) The game's current contested regions (each a `{ regionKey,
+   * parties }` pair — a war frontline in no nation's territory and not in
+   * `unowned`). Emitted verbatim (even when empty) so the model knows which
+   * regions are frontlines (and can `resolve` them or see their parties);
+   * omitted entirely when undefined.
+   */
+  contested?: ContestedRegion[],
 ): string {
   const player = state.nations[state.playerNationId];
   const playerName = player?.name ?? state.playerNationId;
@@ -503,6 +517,7 @@ export function buildUserPrompt(
     nationResources,
     industryProjects,
     seaZones,
+    contested,
   };
   Object.assign(payload, ABILITIES[0].payload(upCtx)); // takeovers → takeoverRisks
   if (noMansLand !== undefined) payload.unowned = noMansLand;
@@ -512,6 +527,7 @@ export function buildUserPrompt(
   Object.assign(payload, ABILITIES[3].payload(upCtx)); // economy → trades, embargoes
   Object.assign(payload, ABILITIES[4].payload(upCtx)); // industry → resources, industry
   Object.assign(payload, ABILITIES[10].payload(upCtx)); // sea → seaZones (always emitted)
+  Object.assign(payload, ABILITIES[11].payload(upCtx)); // contested → contested (only when non-empty)
   return JSON.stringify(payload, null, 2);
 }
 
@@ -653,6 +669,7 @@ export function validateTurnResult(
     disasters: { events: [] },
     migration: { ops: [] },
     sea: { control: [] },
+    contested: { open: [], resolve: [] },
     markers: { add: [], remove: [] },
   };
 
@@ -940,6 +957,9 @@ export function applyTurnResult(
   // (v0.43.0, #65) sea-zone control; a legacy/corrupt clone without the field
   // starts empty (the turn then upserts this turn's claims into it).
   next.seaZones = next.seaZones ?? [];
+  // (v0.44.0, #66) contested regions (war frontlines); a legacy/corrupt clone
+  // without the field starts empty (the turn then opens/resolves contests).
+  next.contested = next.contested ?? [];
   const actingTurn = state.turn; // this action resolves the current turn
   next.turn = state.turn + 1; // then we advance to the next turn to play
   next.date = isDateLike(result.date) ? result.date : addDays(state.date, 2);
@@ -1035,12 +1055,34 @@ export function applyTurnResult(
     }
     set.add(gainer);
   }
+  // (v0.44.0, #66) Contested-region guard for the claims step below: a region
+  // that is currently a war frontline (in `state.contested`) sits in no
+  // nation's territory, so a normal `gain` would otherwise treat it as a free
+  // re-claim. A contested key may only be claimed by a normal claim when this
+  // same turn resolves the contest AND the gainer is one of the contesting
+  // parties (a party re-claim); otherwise the frontline stays contested for
+  // the contested layer (later in the turn) to decide its fate.
+  const contestedBefore = new Set((state.contested ?? []).map((c) => c.regionKey));
+  const resolveThisTurn = new Set(result.contested.resolve);
+  const contestedParties = new Map(
+    (state.contested ?? []).map((c) => [c.regionKey, c.parties]),
+  );
   for (const [key, claiming] of claimants) {
     if (claiming.size !== 1) continue; // double claim: the key stays as it was
     const gainer = [...claiming][0];
     const owner = ownerOf.get(key); // undefined: no owner; '': 2+ owners (corrupt)
     if (owner === '') continue; // pre-existing double ownership: never touched
     if (owner !== undefined && owner === gainer) continue; // self-gain: no-op
+    // (v0.44.0, #66) a currently-contested frontline is not a normal claim
+    // target: a claim on it only proceeds when this turn resolves the contest
+    // and the gainer is one of the contesting parties (a party re-claim);
+    // otherwise the frontline stays contested for the contested layer below.
+    if (
+      contestedBefore.has(key) &&
+      (!resolveThisTurn.has(key) || !contestedParties.get(key)?.includes(gainer))
+    ) {
+      continue;
+    }
     // (v0.30, #50) MILITARY HARD GATE: a CONTESTED conquest (the key has a
     // different sole owner) only proceeds when the attacker's derived military
     // is not MORE than CONQUEST_MILITARY_MARGIN below the defender's. A
@@ -1620,6 +1662,10 @@ export async function runTurn(opts: {
     // (v0.43.0, #65) the current sea-zone control (always emitted — even when
     // empty — so the model knows who controls which of the fixed sea zones).
     state.seaZones ?? [],
+    // (v0.44.0, #66) the current contested regions (war frontlines) — emitted
+    // verbatim (even when empty) so the model knows which regions are
+    // frontlines and can resolve them.
+    state.contested ?? [],
   );
   const nudge =
     'Your previous output was invalid. Respond with ONLY the JSON object described above for this batch — no prose, no fences.';

server/index.ts

@@ -192,6 +192,8 @@ app.post('/api/games', (req: Request, res) => {
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
   // v0.19 (#16 P1): expand each nation's ISO_A3 country list to the region keys
   // of all its sub-regions, so ownership (and the choropleth) is at region

server/map.test.ts

@@ -61,6 +61,8 @@ const state: GameState = {
   industry: [],
   // (v0.43.0, #65) no sea-zone control on a fresh state.
   seaZones: [],
+  // (v0.44.0, #66) no contested regions on a fresh state.
+  contested: [],
 };
 
 // The RegionMap built from the fixture: the authoritative region key → owner source.

server/protocol.test.ts

@@ -50,6 +50,8 @@ function mkState(
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
   if (regionStats !== undefined) base.regionStats = regionStats as GameState['regionStats'];
   else delete (base as { regionStats?: unknown }).regionStats; // simulate a legacy row

server/regions.test.ts

@@ -120,6 +120,8 @@ describe('regions (region-key loader, v0.19 #16 P1)', () => {
       industry: [],
       // (v0.43.0, #65) no sea-zone control on a fresh state.
       seaZones: [],
+      // (v0.44.0, #66) no contested regions on a fresh state.
+      contested: [],
     };
     // 16 GBR sub-regions + 42 FRA sub-regions, no overlap between the two.
     expect(allTerritoryKeys(state).size).toBe(58);

server/stub.ts

@@ -108,6 +108,13 @@ export interface StubPayload {
    * deterministicTurn), so the sea path is covered by unit tests only.
    */
   seaZones?: Array<{ zone: string; by: string }>;
+  /**
+   * (v0.44.0, #66) The currently contested regions (war frontlines,
+   * `{ regionKey, parties }`), emitted by the engine's user prompt. The stub
+   * ignores this field — it never opens or resolves a contest (see
+   * deterministicTurn), so the contested path is covered by unit tests only.
+   */
+  contested?: Array<{ regionKey: string; parties: string[] }>;
 }
 
 function truncate(s: string, n: number): string {
@@ -193,6 +200,11 @@ function truncate(s: string, n: number): string {
  * (v0.43.0, #65) The stub likewise NEVER claims, contests or re-claims a sea
  * zone (it always returns `sea: { control: [] }`) — the sea-control path is
  * covered by unit tests only, keeping the e2e assertions untouched.
+ *
+ * (v0.44.0, #66) The stub likewise NEVER opens or resolves a contested region
+ * (a war frontline) — it always returns `contested: { open: [], resolve: [] }`
+ * — the contested path is covered by unit tests only, keeping the e2e
+ * assertions untouched.
  */
 export function deterministicTurn(p: StubPayload): TurnResult {
   const state = p.state;
@@ -272,13 +284,14 @@ export function deterministicTurn(p: StubPayload): TurnResult {
     nationOps: [], // the stub never proposes nation ops (see doc comment)
   };
 
-  // The 11 ability fields, filled by the registry in its canonical order. The
+  // The 12 ability fields, filled by the registry in its canonical order. The
   // stub is ability-inert: every ability contributes its own no-op default
   // (each ability's `stub()` — see the per-ability doc comments above), so the
   // e2e assertions are unaffected. The insertion order here (ABILITIES) is the
   // historical key order pinned by the stub's deterministic output
   // (takeovers → wars → hybrid → economy → industry → nuclear → leaders →
-  // ideology → disasters → migration → sea), which must stay byte-identical.
+  // ideology → disasters → migration → sea → contested), which must stay
+  // byte-identical.
   const abilities = {} as Record<AbilityField, unknown>;
   for (const a of ABILITIES) abilities[a.field] = a.stub();
 

shared/protocol.ts

@@ -783,6 +783,53 @@ export interface SeaOps {
   control: SeaControlOp[];
 }
 
+/**
+ * (v0.44.0, #66) A single `open` op: make a region **contested** — a war
+ * frontline that is in **no** nation's `territory` and not in `unowned` (a
+ * third region state, besides "owned by one nation" and "no man's land").
+ * `regionKey` is the region key (or a resolvable region name); `parties` are
+ * two or more nation refs (ids or names), resolved via the shared
+ * `resolveNationRef` — the stored `ContestedRegion.parties` are the resolved
+ * nation ids.
+ */
+export interface ContestOp {
+  /** The region key to make contested (the model names it by key or name). */
+  regionKey: string;
+  /**
+   * The nations contesting the region — two or more refs (ids or names). At
+   * least two distinct, resolvable nations are required, and the region's
+   * sole owner (if any) must be at war with one of them (or, for a
+   * no-man's-land region, two of the parties must be at war with each other).
+   */
+  parties: string[];
+}
+
+/**
+ * The contested-region block of a `TurnResult`. Required; default
+ * `{ open: [], resolve: [] }`. `open` makes a region a contested frontline
+ * (it leaves its owner's `territory` and `unowned` — sole ownership is
+ * preserved); `resolve` ends a contest, releasing the region to no man's
+ * land — unless a concurrent winning claim by one of the parties re-owns it
+ * (re-initialising its `regionStats`).
+ */
+export interface ContestedOps {
+  /** Regions to make contested this turn. */
+  open: ContestOp[];
+  /** Region keys to resolve (release to no man's land) this turn. */
+  resolve: string[];
+}
+
+/**
+ * A contested region — a region key that is a war frontline: in **no**
+ * nation's `territory` and not in `unowned`, contested by `parties` (resolved
+ * nation ids, two or more). Stored in `GameState.contested` (unique by
+ * `regionKey`).
+ */
+export interface ContestedRegion {
+  regionKey: string;
+  parties: string[];
+}
+
 /** The exact JSON object the world-simulator LLM must return for a turn. */
 export interface TurnResult {
   date: string;
@@ -992,6 +1039,19 @@ export interface TurnResult {
    * `{ control: [] }`.
    */
   sea: SeaOps;
+  /**
+   * (v0.44.0, #66) Contested regions / frontlines: `open` makes a region a
+   * contested war frontline (it leaves its owner's `territory` and `unowned`
+   * — a third region state in no territory and not no man's land — and is
+   * contested by two or more nations at war); `resolve` ends a contest,
+   * releasing the region to no man's land unless a concurrent winning claim
+   * by one of the parties re-owns it. A region with a sole owner not at war
+   * with any party, or two or more owners, cannot be contested. Sole
+   * ownership is never broken; a still-contested key is not a valid normal
+   * claim target. At most 1–2 per turn, each narrated in `events`. Required;
+   * default `{ open: [], resolve: [] }`.
+   */
+  contested: ContestedOps;
   /**
    * (v0.27, #44) Map-marker ops this turn. `add` places new named markers
    * (the engine positions each at its region's centroid + a small
@@ -1233,6 +1293,27 @@ export const UNOWNED_STROKE = 'rgba(255,255,255,0.14)';
 /** The border of an owned region (brighter than unowned). */
 export const OWNED_STROKE = 'rgba(255,255,255,0.30)';
 
+/**
+ * The distinct, visible fill + stroke for a **contested** region (a war
+ * frontline — a key that is in no nation's `territory` and not in `unowned`).
+ * Reddish/orange to read as a "hot" frontline on the dark basemap — clearly
+ * distinct from a nation color and from the no-man's-land grey. The contested
+ * state is decided by the client (via `GameState.contested`), never by the
+ * `RegionMap` (which only knows owned vs absent).
+ */
+export const CONTESTED_FILL = '#f97316';
+export const CONTESTED_STROKE = 'rgba(255,237,213,0.55)';
+
+/**
+ * The hover-tooltip sub-line for a contested region: a short "Contested:
+ * A vs B" line naming the contesting parties. A missing party name (a nation
+ * removed by a merge/split) degrades to a dash, never crashes.
+ */
+export function contestedTooltipLabel(parties: string[]): string {
+  const names = parties.map((p) => p || '—');
+  return `Contested: ${names.join(' vs ')}`;
+}
+
 /** The hover-tooltip sub-line for a region with no owning nation. */
 export function unownedTooltipLabel(isNoMansLand: boolean): string {
   return isNoMansLand ? "No man's land" : 'No owner';

shared/scenario.ts

@@ -463,6 +463,8 @@ export function worldDraftToGameState(
     industry: [],
     // (v0.43.0, #65) no sea-zone control on a fresh state.
     seaZones: [],
+    // (v0.44.0, #66) no contested regions on a fresh state.
+    contested: [],
   };
   return state;
 }

shared/types.ts

@@ -3,7 +3,7 @@
 // (The single `import type` below erases at compile time, so no runtime
 // dependency on protocol.ts is introduced — see the GameState.pendingNationOps
 // doc comment.)
-import type { NationOp } from './protocol';
+import type { NationOp, ContestedRegion } from './protocol';
 
 /** A nation's 0–100 status indices. Every value is clamped to 0–100 by the engine. */
 export interface NationStats {
@@ -474,6 +474,18 @@ export interface GameState {
    * server/db.ts) — additive, no data wipe.
    */
   seaZones: SeaZoneClaim[];
+  /**
+   * (v0.44.0, #66) Contested regions / frontlines (see {@link ContestedRegion}):
+   * one entry per region key that is a war frontline — a key in **no** nation's
+   * `territory` and not in `unowned`, contested by two or more nations at war.
+   * A region becomes contested when a turn's `contested.open` succeeds (it
+   * leaves its owner's `territory` and `unowned` — sole ownership is preserved);
+   * it is resolved (released to no man's land, or re-claimed by a party) by a
+   * later `contested.resolve`. At most ONE entry per region key (unique by
+   * `regionKey`). Always `[]` on a fresh game; rows saved before v0.44 load
+   * with this defaulted to `[]` (see server/db.ts) — additive, no data wipe.
+   */
+  contested: ContestedRegion[];
 }
 
 /**

src/App.tsx

@@ -834,6 +834,7 @@ function GameScreen({
         unowned={game.unowned ?? []}
         markers={game.markers ?? []}
         regionStats={game.regionStats ?? {}}
+        contested={game.contested ?? []}
         onFocusNation={focusNation}
       />
 

src/components/WorldMap.tsx

@@ -9,11 +9,15 @@ import 'maplibre-gl/dist/maplibre-gl.css';
 import workerUrl from 'maplibre-gl/dist/maplibre-gl-worker.mjs?url';
 maplibregl.setWorkerUrl(workerUrl);
 import {
+  CONTESTED_FILL,
+  CONTESTED_STROKE,
+  contestedTooltipLabel,
   mapFeatureOwner,
   MARKER_TYPE_INFO,
   nationColor,
   regionFillStyle,
   unownedTooltipLabel,
+  type ContestedRegion,
   type RegionMap,
   type RegionOwner,
 } from '@shared/protocol';
@@ -146,6 +150,12 @@ function cameraForPreset(presetId: string): { center: [number, number]; zoom: nu
  * no man's land mid-game (`GameState.unowned`) — gets the distinct visible grey
  * (`NO_MANS_LAND_FILL`); every other ownerless region keeps the faint
  * preset-unassigned look. Both come from the shared `regionFillStyle` contract.
+ *
+ * (v0.44.0, #66) A **contested** region (a war frontline — `contestedSet`, from
+ * `GameState.contested`) takes precedence over both unowned looks: it is in no
+ * nation's territory and not no man's land, so it renders the distinct
+ * reddish/orange `CONTESTED_FILL` / `CONTESTED_STROKE`. The state is decided by
+ * the client, never by the RegionMap (which has no entry for a contested key).
  */
 function applyRegions(
   geo: FeatureCollection,
@@ -153,6 +163,7 @@ function applyRegions(
   playerNationId: string,
   idKey: Record<string, string>,
   unownedSet: ReadonlySet<string>,
+  contestedSet: ReadonlySet<string>,
 ): FeatureCollection {
   const out: FeatureCollection = JSON.parse(JSON.stringify(geo));
   for (const f of out.features) {
@@ -165,6 +176,18 @@ function applyRegions(
     // key the RegionMap by it — never the sub-region id or the repacked id.
     const key = idKey[subId] ?? '';
     f.properties.regionKey = key;
+    // (v0.44.0, #66) A contested frontline takes precedence over every other
+    // state (owned, unowned, no man's land): the key is in no nation's
+    // territory and not no man's land, so it renders the distinct contested
+    // fill/stroke (decided by the client from `GameState.contested`, never by
+    // the RegionMap, which has no entry for it).
+    if (key !== '' && contestedSet.has(key)) {
+      f.properties.fill = CONTESTED_FILL;
+      f.properties.stroke = CONTESTED_STROKE;
+      f.properties.owner = '';
+      f.properties.ownerId = '';
+      f.properties.isPlayer = 0;
+    } else {
       const r = key ? regions[key] : undefined;
       if (r) {
         const style = regionFillStyle(r, false);
@@ -184,6 +207,7 @@ function applyRegions(
         f.properties.isPlayer = 0;
       }
     }
+  }
   return out;
 }
 
@@ -412,8 +436,14 @@ function hoverHtml(
   noMansLand = false,
   regionKey?: string,
   regionStats?: Record<string, RegionStats>,
+  contestedParties?: string[],
 ): string {
   if (!region || !nation) {
+    // (v0.44.0, #66) A contested frontline (a region in no nation's territory
+    // and not no man's land) names its contesting parties in the sub-line.
+    if (contestedParties && contestedParties.length > 0) {
+      return `<div class="hm-popup"><div class="hm-popup-title">${esc(subRegionName || 'Contested')}</div><div class="hm-popup-sub">${contestedTooltipLabel(contestedParties)}</div></div>`;
+    }
     return `<div class="hm-popup"><div class="hm-popup-title">${esc(subRegionName || 'Unclaimed')}</div><div class="hm-popup-sub">${unownedTooltipLabel(noMansLand)}</div></div>`;
   }
   // (v0.29, #46 PR 2) The region's OWN per-region stats (not the nation's
@@ -479,6 +509,15 @@ interface Props {
    * stats.
    */
   regionStats?: Record<string, RegionStats>;
+  /**
+   * (v0.44.0, #66) The game's contested regions / war frontlines
+   * (`GameState.contested` — a region key + its contesting party ids). Such a
+   * region is in no nation's territory and not no man's land (a third region
+   * state): it renders the distinct reddish/orange `CONTESTED_FILL` and its
+   * hover tooltip names the parties. The map legend is unaffected (a
+   * contested key is absent from the RegionMap, so it adds no entry).
+   */
+  contested?: ContestedRegion[];
 }
 
 /**
@@ -536,6 +575,7 @@ export default function WorldMap({
   onFocusNation,
   markers,
   regionStats,
+  contested,
 }: Props) {
   const containerRef = useRef<HTMLDivElement>(null);
   const mapRef = useRef<maplibregl.Map | null>(null);
@@ -553,6 +593,10 @@ export default function WorldMap({
   const markersRef = useRef<MapMarker[]>(markers ?? []);
   // (v0.29, #46 PR 2) latest per-region stats, for the hover tooltip.
   const regionStatsRef = useRef<Record<string, RegionStats>>(regionStats ?? {});
+  // (v0.44.0, #66) latest contested regions, region key -> contesting party
+  // NAMES (the stored parties are resolved nation ids, resolved here so the
+  // hover tooltip can show "Contested: A vs B").
+  const contestedRef = useRef<Map<string, string[]>>(new Map());
   regionsRef.current = regions;
   nationsRef.current = nations;
   playerRef.current = playerNationId;
@@ -561,6 +605,11 @@ export default function WorldMap({
   onFocusNationRef.current = onFocusNation;
   markersRef.current = markers ?? [];
   regionStatsRef.current = regionStats ?? {};
+  {
+    const m = new Map<string, string[]>();
+    for (const c of contested ?? []) m.set(c.regionKey, c.parties.map((id) => nations[id]?.name ?? id));
+    contestedRef.current = m;
+  }
 
   // Diffing state for the transient territory-change flash (owned by this component
   // so a resync with identical data never re-flashes).
@@ -721,9 +770,12 @@ export default function WorldMap({
       const pKey = f.properties?.regionKey;
       const keyStr = typeof pKey === 'string' && pKey !== '' ? pKey : undefined;
       const noMansLand = !region && keyStr !== undefined && unownedRef.current.has(keyStr);
+      // (v0.44.0, #66) a contested frontline (in no territory, not no man's
+      // land) names its contesting parties in the tooltip sub-line.
+      const contestedParties = !region && keyStr !== undefined ? contestedRef.current.get(keyStr) : undefined;
       hoverPopup
         .setLngLat(e.lngLat)
-        .setHTML(hoverHtml(p?.name ?? subId, region, nation, noMansLand, keyStr, regionStatsRef.current))
+        .setHTML(hoverHtml(p?.name ?? subId, region, nation, noMansLand, keyStr, regionStatsRef.current, contestedParties))
         .addTo(map);
       map.getCanvas().style.cursor = 'pointer';
     };
@@ -799,7 +851,7 @@ export default function WorldMap({
       const idKey = idKeyRef.current;
       const src = map.getSource(REGIONS_SOURCE) as GeoSource | undefined;
       if (!geo || !idKey || !src) return;
-      src.setData(applyRegions(geo, regionsRef.current, playerRef.current, idKey, unownedRef.current));
+      src.setData(applyRegions(geo, regionsRef.current, playerRef.current, idKey, unownedRef.current, new Set(contestedRef.current.keys())));
     };
 
     // Stamp the current markers onto the marker source (v0.27, #44).
@@ -977,7 +1029,7 @@ export default function WorldMap({
 
     if (map && geo && idKey) {
       const src = map.getSource(REGIONS_SOURCE) as GeoSource | undefined;
-      if (src) void src.setData(applyRegions(geo, cur, playerNationId, idKey, unownedSet));
+      if (src) void src.setData(applyRegions(geo, cur, playerNationId, idKey, unownedSet, new Set(contestedRef.current.keys())));
     }
 
     if (wasPrimed && prev && idKey) {
@@ -989,7 +1041,9 @@ export default function WorldMap({
       // up as ownerId changes above, so they flash like any other transfer.
       if (changed.size > 0) flashApiRef.current?.([...changed]);
     }
-  }, [regions, playerNationId, unowned]);
+    // (v0.44.0, #66) re-paint when the contested set changes too — a contested
+    // key is absent from the RegionMap, so the diff alone wouldn't repaint it.
+  }, [regions, playerNationId, unowned, contested]);
 
   // (v0.27, #44) Repaint the marker symbol layer whenever the marker list
   // changes (a turn placed/removed markers) or the nations record changes