Support group Harkonnen traitor calls

components/game-table.tsx

@@ -390,10 +390,10 @@ export function GameTable({
   const canActivateKarama = (card: Card) => canSpendKarama(card, kullSpecialPurpose(me.faction));
   const traitorBattle = g.battle;
   const traitorBeneficiary =
-    traitorBattle &&
+    traitorBattle?.traitorBeneficiary ?? (traitorBattle &&
     [traitorBattle.attacker, traitorBattle.defender].includes(me.id)
       ? me.id
-      : me.ally;
+      : me.ally);
   const traitorPlan = traitorBattle?.revealed
     ? traitorBattle.plans[
         traitorBattle.attacker === traitorBeneficiary

docs/CURRENT_STATUS.md

@@ -17,6 +17,14 @@ open mode gates.
 
 ## Current checkpoint and work
 
+**Staged group Harkonnen traitor support — 28 October. Prototyped / Partial.**
+Harkonnen can use its own traitor in either ally's battle through the native
+vote, Karama and outcome flow. Applying this to two allies is provisional;
+five related files pass 56 cases, including real Nexus, sealed plans, calls,
+outcomes and server-rendered controls after a staged position. Other group
+abilities and normal lobby access remain unfinished.
+[Scope](OPTIONAL_ALLIANCE_VICTORY.md#group-harkonnen-traitor-support--28-october-2026).
+
 **Staged group Voice and Prescience — 28 October. Prototyped / Partial.**
 Bene Gesserit and Atreides can offer their native battle powers for either
 ally in a staged Basic classic group; the same beneficiary quote is used by
@@ -310,7 +318,10 @@ Run 12 was canceled before starting; run 21 for `1eeeb32` passed 25
 administrator and 69 HTTP checks, origin/restart/replacement verification,
 and published both revision and checkpoint tags with digest
 `sha256:fbfc252a46f2ee900e4640e1ef8ad29c0605088267b992f42fe2fa5519dc91db`.
-Run 22 was canceled before starting; run 23 for `9081249` was running at the
+Run 22 was canceled before starting; run 23 for `9081249` succeeded and
+published revision and checkpoint tags with digest
+`sha256:ca98dec808c4e9709241c5a2e5ebca144941eb700ee538fed89904455600d886`.
+Run 24 was canceled before starting; run 25 for `83ccd71` was running at the
 last check.
 Deployment remains unverified.
 Existing NAS deployment and its persistent storage remain untouched.

docs/OPTIONAL_ALLIANCE_VICTORY.md

@@ -83,6 +83,16 @@ single-ally wording to both group members is provisional. Advanced, expansion
 factions and optional modules remain outside this prototype, and normal
 group starts are not yet available.
 
+## Group Harkonnen traitor support — 28 October 2026
+
+In the unexposed Basic classic group prototype, Harkonnen may call its held
+traitor against the opponent of either allied combatant. The choice remains
+Harkonnen's, and the native allied-call Karama response, other combatants'
+votes, mutual calls and battle resolution continue through the existing
+windows. Applying the printed single-ally power to both group members is a
+provisional interpretation. Other profiles and normal lobby access remain
+separate; the remaining group abilities and interactions are unfinished.
+
 ## Group Nexus negotiation — 28 October 2026
 
 **Integrated groundwork, not a selectable game mode.** In a staged Basic

docs/RULE_DECISIONS.md

@@ -1,5 +1,10 @@
 # Rule decision index
 
+## Group Harkonnen traitor support — 28 October 2026
+
+The staged Basic group prototype provisionally allows Harkonnen to support
+either ally's battle with its own held traitor. [Scope](OPTIONAL_ALLIANCE_VICTORY.md#group-harkonnen-traitor-support--28-october-2026).
+
 ## Group Voice and Prescience — 28 October 2026
 
 The staged Basic group prototype provisionally applies these native alliance

game/bots.ts

@@ -4125,9 +4125,9 @@ function policyActions(g: GameView): Action[] {
     if (b.revealed) {
       const ownsTraitorDecision =
         b.traitorVoters.includes(me.id) && !b.traitorSubmitted.includes(me.id);
-      const beneficiary = [b.attacker, b.defender].includes(me.id)
+      const beneficiary = b.traitorBeneficiary ?? ([b.attacker, b.defender].includes(me.id)
         ? me.id
-        : me.ally;
+        : me.ally);
       const enemy = b.attacker === beneficiary ? b.defender : b.attacker;
       const preferredCall =
         ownsTraitorDecision &&

game/engine.ts

@@ -3939,8 +3939,12 @@ function nexusTraitorParentSignature(g: Game, event: string) {
 function traitorDeclarationContext(g: Game): TraitorDeclarationContext {
   const b = g.battle!;
   return { event: b.event!, attacker: b.attacker, defender: b.defender, plans: b.plans,
+    status: g.status, advanced: g.advanced, coalitionState: g.coalitionState, expansions: g.expansions,
+    homeworlds: g.homeworlds, nexusCards: g.nexusCards, leaderSkills: g.leaderSkills,
+    techTokens: g.techTokens, strongholdCards: g.strongholdCards, ecazTreachery: g.ecazTreachery,
+    discoveryEnabled: g.discoveryEnabled,
     ...(b.ecazOccupy ? { ecazOccupy: ecazBattleProfile(g)! } : {}),
-    players: g.players.map(({id,faction,ally,traitors}) => ({id,faction,ally,traitors})),
+    players: g.players.map(({id,faction,ally,allySinceTurn,traitors}) => ({id,faction,ally,allySinceTurn,traitors})),
     heroLeaderIds: physicalTreacheryCards(g).filter(c => c.kind === 'hero').map(c => c.id),
   };
 }
@@ -32545,9 +32549,10 @@ function traitorVoters(g: Game, b: Battle) {
     for (const owner of [b.ecazOccupy.ecaz, b.ecazOccupy.ally])
       if (!voters.includes(owner)) voters.push(owner);
   const harkonnen = byFaction(g, 'harkonnen');
+  const harkonnenBeneficiary = harkonnen && coalitionBattleBeneficiary(g, harkonnen.id, b.attacker, b.defender);
   if (
-    harkonnen?.ally &&
+    harkonnen && harkonnenBeneficiary &&
-    voters.includes(harkonnen.ally) &&
+    voters.includes(harkonnenBeneficiary) &&
     !voters.includes(harkonnen.id)
   )
     voters.push(harkonnen.id);
@@ -32555,7 +32560,7 @@ function traitorVoters(g: Game, b: Battle) {
 }
 function traitorBeneficiary(g: Game, b: Battle, id: string) {
   if (b.ecazOccupy?.lead && [b.ecazOccupy.ecaz, b.ecazOccupy.ally].includes(id)) return b.ecazOccupy.lead;
-  return [b.attacker, b.defender].includes(id) ? id : getPlayer(g, id).ally;
+  return coalitionBattleBeneficiary(g, id, b.attacker, b.defender);
 }
 /** One native eligibility quote for declarations and private Truthtrance answers. */
 function traitorCallBlock(g: Game, b: Battle, id: string, held = getPlayer(g, id).traitors): string | null {
@@ -47453,6 +47458,7 @@ export function viewGame(state: Game, id: string, now?: number) {
               ? { [id]: b.plans[id] }
               : {},
           traitorSubmitted: Object.keys(b.traitorCalls),
+          traitorBeneficiary: traitorVoters(g, b).includes(id) ? traitorBeneficiary(g, b, id) : null,
           traitorCallChoices: (() => { const context = traitorTruthContext(g, id); return context
             ? turnActionTraitorChoices(g, id,
               traitorDecisionRule(() => traitorDecisionChoices(context, b.traitorDecisionPromises ?? []))) : null; })(),

game/reference.ts

@@ -4500,11 +4500,11 @@ export const RULE_TOPICS: RuleTopic[] = [
     example:
       'At the final turn with neither Guild nor Fremen, two players each hold two qualifying strongholds and a third holds one. The two leaders of the count share the win.',
     checklist: [
-      { area: 'Implementation', status: 'Partial', detail: 'A host-selectable shorter two-member target shares victory calculation. Unexposed staged Basic groups connect Nexus, selected funding, Emperor and Fremen aid, and native Voice and Prescience; other group benefits remain open.', evidence: ['game/alliance-victory-option.ts', 'game/victory-progress.ts', 'game/victory-quote.ts', 'game/engine.ts', 'game/coalition-battle-preparation.ts', 'game/terminal-cancellation.ts'] },
+      { area: 'Implementation', status: 'Partial', detail: 'A host-selectable shorter two-member target shares victory calculation. Unexposed staged Basic groups connect Nexus, selected funding, Emperor and Fremen aid, Voice, Prescience and Harkonnen traitor support; other group benefits remain open.', evidence: ['game/alliance-victory-option.ts', 'game/victory-progress.ts', 'game/victory-quote.ts', 'game/engine.ts', 'game/coalition-battle-preparation.ts', 'game/traitor-declarations.ts', 'game/terminal-cancellation.ts'] },
       { area: 'Player controls', status: 'Partial', detail: 'The lobby offers the pair option. A staged group Emperor can choose either ally for spice and extra revival; group games cannot yet be started from the lobby.', evidence: ['components/game-table.tsx', 'components/coalition-emperor-aid.tsx', 'tests/short-alliance-victory-controls.test.tsx'] },
       { area: 'AI', status: 'Partial', detail: 'Legal alliance and victory paths use the shared target; staged group Emperor bots can offer a targeted revival. Strategic tuning remains deferred.', evidence: ['game/bots.ts', 'game/victory-progress.ts'] },
       { area: 'Documentation', status: 'Partial', detail: 'The printed option and provisional two-controller precedence are recorded.', evidence: ['docs/OPTIONAL_ALLIANCE_VICTORY.md'] },
-      { area: 'Verification', status: 'Partial', detail: 'Focused pair and staged group evidence includes real Nexus actions, Emperor and Fremen aid and battle preparation; larger alliances and full combinations remain open.', evidence: ['tests/alliance-victory-option.test.ts', 'tests/short-alliance-victory-runtime.test.ts', 'tests/coalition-emperor-aid.test.ts', 'tests/coalition-fremen-revival.test.ts', 'tests/coalition-battle-preparation.test.ts', 'tests/coalition-battle-power-question.test.ts'] },
+      { area: 'Verification', status: 'Partial', detail: 'Focused pair and staged group evidence includes real Nexus actions, Emperor and Fremen aid, battle preparation and allied traitor votes; larger alliances and full combinations remain open.', evidence: ['tests/alliance-victory-option.test.ts', 'tests/short-alliance-victory-runtime.test.ts', 'tests/coalition-emperor-aid.test.ts', 'tests/coalition-fremen-revival.test.ts', 'tests/coalition-battle-preparation.test.ts', 'tests/coalition-battle-power-question.test.ts', 'tests/coalition-harkonnen-traitor.test.ts', 'tests/coalition-traitor-declarations.test.ts'] },
     ],
     related: [
       'mentat',

game/traitor-declarations.ts

@@ -1,8 +1,9 @@
 import { FACTIONS, type FactionId } from './catalog';
 import { CHEAP_HERO_TRAITOR } from './traitors';
 import { quoteEcazOccupyBattle, type EcazOccupyBattleProfile } from './ecaz-occupy-battle';
+import { coalitionBattleBeneficiary, type CoalitionBattlePreparationContext } from './coalition-battle-preparation';
 
-export type TraitorDeclarationContext = {
+export type TraitorDeclarationContext = Omit<Partial<CoalitionBattlePreparationContext>, 'players'> & {
   ecazOccupy?: EcazOccupyBattleProfile;
   event: string;
   attacker: string;
@@ -12,6 +13,7 @@ export type TraitorDeclarationContext = {
     id: string;
     faction: FactionId;
     ally?: string | null;
+    allySinceTurn?: number;
     traitors: readonly string[];
   }[];
   heroLeaderIds: readonly string[];
@@ -98,7 +100,9 @@ function declaredElements(context: TraitorDeclarationContext, voter: string) {
   const combatants = [context.attacker, context.defender];
   const occupy = context.ecazOccupy;
   const coSide = !!occupy && [occupy.ecaz, occupy.ally].includes(voter);
-  const beneficiary = coSide ? occupy.lead : combatants.includes(voter) ? voter : owner.ally;
+  const beneficiary = coSide ? occupy.lead : combatants.includes(voter) ? voter :
+    owner.faction === 'harkonnen' ? coalitionBattleBeneficiary(
+      {...context, status: context.status ?? ''}, voter, context.attacker, context.defender) : null;
   requireDeclaration(
     beneficiary &&
       combatants.includes(beneficiary) &&

tests/coalition-harkonnen-traitor.test.ts

@@ -0,0 +1,199 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { registerHooks } from 'node:module';
+import { readFileSync } from 'node:fs';
+import { createElement } from 'react';
+import { renderToStaticMarkup } from 'react-dom/server';
+import { baseDeck } from '../game/cards';
+import { coalitionOf, emptyCoalitionState } from '../game/coalition-alliance';
+import { botActions } from '../game/bots';
+import { applyAction, battles, createGame, newPlayer, viewGame, type Action, type Game } from '../game/engine';
+import { traitorDeck } from '../game/traitors';
+
+const aliases = registerHooks({
+  resolve(specifier, context, next) {
+    return next(specifier === 'next/image' ? 'vinext/shims/image' :
+      specifier === 'next/link' ? 'vinext/shims/link' : specifier, context);
+  },
+  load(url, context, next) {
+    if (!url.endsWith('.module.css')) return next(url, context);
+    const css = readFileSync(new URL(url), 'utf8');
+    const classes = Object.fromEntries([...css.matchAll(/\.([a-zA-Z_][\w-]*)/g)].map(match => [match[1], match[1]]));
+    return {format:'module', source:`export default ${JSON.stringify(classes)}`, shortCircuit:true};
+  },
+});
+const {GameTable} = await import('../components/game-table');
+aliases.deregister();
+
+const send = (game: Game, id: string, action: Action) => applyAction(game, id, action);
+const player = (game: Game, id: string) => game.players.find(seat => seat.id === id)!;
+const physicalTraitors = (game: Game) => [
+  ...(game.traitorReserve ?? []), ...game.players.flatMap(seat => [...seat.traitors, ...seat.traitorChoices]),
+].sort();
+
+/** Three-member groups cannot be started in the lobby. Stage a Nexus, form
+ * the pair and group through actual actions, then stage conserved forces in
+ * Arrakeen and transfer physical Traitor identities out of their reserve. */
+function source(ally: 'e' | 'f' | 'h', options: { group?: boolean; mutual?: boolean } = {}) {
+  let game = createGame('GROUPTRAITOR', newPlayer('h', 'Harkonnen', 'harkonnen'), false);
+  game.players.push(newPlayer('e', 'Emperor', 'emperor'), newPlayer('f', 'Fremen', 'fremen'),
+    newPlayer('g', 'Guild', 'guild'));
+  Object.assign(game, {status:'playing', phase:1, turn:2, nexus:true, order:['h','e','f','g'],
+    ready:[], storm:18, deck:baseDeck(), response:null, decision:null, phaseOpening:null});
+  game.coalitionState = emptyCoalitionState();
+  game = send(game, 'h', {type:'alliance', target:'e'});
+  game = send(game, 'e', {type:'alliance', target:'h'});
+  if (options.group !== false) {
+    const pair = coalitionOf(game.players, game.coalitionState, 'h'); assert.ok(pair);
+    game = send(game, 'h', {type:'coalitionPropose', groupId:pair.id, entrant:'f',
+      expectedRevision:game.coalitionState!.revision});
+    for (const id of ['e','f']) {
+      const proposal = game.coalitionState!.proposal!;
+      game = send(game, id, {type:'coalitionAnswer', event:proposal.event, nexus:proposal.nexus,
+        turn:proposal.turn, accept:true, expectedRevision:game.coalitionState!.revision});
+    }
+    assert.deepEqual(coalitionOf(game.players, game.coalitionState, 'h')!.members, ['e','f','h']);
+  }
+  Object.assign(game, {phase:6, nexus:false, ready:[], response:null, decision:null,
+    phaseOpening:null, battle:null});
+  for (const seat of game.players) {
+    seat.forces = {}; seat.reserves = 20; seat.tanks = 0; seat.spice = 10;
+    seat.hand = []; seat.traitors = []; seat.traitorChoices = [];
+  }
+  for (const id of [ally,'g']) {
+    player(game, id).forces = {'arrakeen:10':4};
+    player(game, id).reserves = 16;
+  }
+  const opponentLeader = player(game, 'g').leaders[0].id;
+  const allyLeader = player(game, ally).leaders[0].id;
+  game.traitorReserve = traitorDeck(game.players);
+  const inventory = physicalTraitors(game);
+  const transfer = (identity: string, holder: string) => {
+    const index = game.traitorReserve!.indexOf(identity); assert.ok(index >= 0);
+    player(game, holder).traitors.push(...game.traitorReserve!.splice(index, 1));
+  };
+  transfer(opponentLeader, 'h');
+  if (options.mutual) transfer(allyLeader, 'g');
+  assert.deepEqual(physicalTraitors(game), inventory);
+  const karamaIndex = game.deck.findIndex(card => card.effect === 'karama'); assert.ok(karamaIndex >= 0);
+  const [karama] = game.deck.splice(karamaIndex, 1); player(game, 'g').hand.push(karama);
+  const choice = battles(game).find(candidate => candidate.territory === 'arrakeen' &&
+    [candidate.attacker,candidate.defender].includes(ally) && [candidate.attacker,candidate.defender].includes('g'));
+  assert.ok(choice);
+  game.active = choice.chooser;
+  const enemy = choice.attacker === choice.chooser ? choice.defender : choice.attacker;
+  game = send(game, choice.chooser, {type:'chooseBattle', territory:'arrakeen', target:enemy});
+  assert.ok(game.battle && !game.battle.preparation);
+  game = send(game, ally, {type:'battlePlan', leader:allyLeader, dial:0, support:0, weapon:null, defense:null});
+  assert.ok(!game.battle?.revealed);
+  game = send(game, 'g', {type:'battlePlan', leader:opponentLeader, dial:0, support:0, weapon:null, defense:null});
+  assert.equal(game.battle?.revealed, true);
+  return {game, ally, opponentLeader, allyLeader, karama, inventory};
+}
+function passResponses(game: Game): Game {
+  for (let count = 0; game.response && count < 24; count++) {
+    const next = game.players.find(seat => !game.response!.passed.includes(seat.id));
+    assert.ok(next);
+    game = send(game, next.id, {type:'passResponse'});
+  }
+  assert.equal(game.response ?? null, null);
+  return game;
+}
+function conserved(game: Game) {
+  for (const seat of game.players)
+    assert.equal(seat.reserves + seat.tanks + Object.values(seat.forces).reduce((a,b) => a+b, 0), 20);
+}
+function reject(game: Game, id: string, action: Action) {
+  const before = structuredClone(game);
+  assert.throws(() => send(game, id, action));
+  assert.deepEqual(game, before);
+}
+
+for (const ally of ['e','f'] as const) {
+  void test(`Harkonnen may reveal its Guild traitor for group ally ${ally}`, () => {
+    const f = source(ally); let game = f.game;
+    const own = viewGame(game, 'h').battle!;
+    assert.ok(own.traitorVoters.includes('h'));
+    assert.equal(own.traitorBeneficiary, ally);
+    assert.ok(own.traitorCallChoices?.includes(true));
+    game = send(game, 'h', {type:'traitorCall', call:true});
+    assert.equal(game.response?.kind, 'harkonnenTraitor');
+    assert.equal(game.battle?.traitorCalls.h, true);
+    game = passResponses(game);
+    game = send(game, ally, {type:'traitorCall', call:false});
+    game = send(game, 'g', {type:'traitorCall', call:false});
+    assert.equal(game.lastBattleContext?.result, 'traitor');
+    assert.equal(game.lastBattleContext?.winner, ally);
+    assert.equal(player(game, 'g').leaders.find(leader => leader.id === f.opponentLeader)?.dead, true);
+    assert.deepEqual(physicalTraitors(game), f.inventory);
+    conserved(game);
+  });
+  void test(`Karama cancels Harkonnen's group traitor call for ${ally}`, () => {
+    const f = source(ally); let game = send(f.game, 'h', {type:'traitorCall', call:true});
+    assert.equal(game.response?.kind, 'harkonnenTraitor');
+    game = send(game, 'g', {type:'card', mode:'cancel', card:f.karama.id});
+    game = passResponses(game);
+    assert.equal(game.battle?.traitorCalls.h, false);
+    reject(game, 'h', {type:'traitorCall', call:true});
+    game = send(game, ally, {type:'traitorCall', call:false});
+    game = send(game, 'g', {type:'traitorCall', call:false});
+    assert.equal(game.lastBattleContext?.result, 'normal');
+    assert.equal(game.discard.filter(card => card.id === f.karama.id).length, 1);
+    assert.deepEqual(physicalTraitors(game), f.inventory);
+    conserved(game);
+  });
+}
+
+void test('an opposing Guild call and Harkonnen group call destroy both sides', () => {
+  const f = source('f', {mutual:true}); let game = send(f.game, 'g', {type:'traitorCall', call:true});
+  game = send(game, 'h', {type:'traitorCall', call:true});
+  game = passResponses(game);
+  game = send(game, 'f', {type:'traitorCall', call:false});
+  assert.equal(game.lastBattleContext?.result, 'mutualTraitors');
+  assert.equal(player(game, 'g').leaders.find(leader => leader.id === f.opponentLeader)?.dead, true);
+  assert.equal(player(game, 'f').leaders.find(leader => leader.id === f.allyLeader)?.dead, true);
+  assert.deepEqual(physicalTraitors(game), f.inventory);
+  conserved(game);
+});
+
+void test('the existing two-member Harkonnen ally call keeps its implicit beneficiary', () => {
+  const f = source('e', {group:false});
+  assert.equal(viewGame(f.game, 'h').battle?.traitorBeneficiary, 'e');
+  const game = send(f.game, 'h', {type:'traitorCall', call:true});
+  assert.equal(game.response?.kind, 'harkonnenTraitor');
+});
+
+void test('Harkonnen still calls its own traitor as a combatant in a group', () => {
+  const f = source('h');
+  assert.equal(viewGame(f.game, 'h').battle?.traitorBeneficiary, 'h');
+  const game = send(f.game, 'h', {type:'traitorCall', call:true});
+  assert.equal(game.battle?.traitorCalls.h, true);
+  assert.notEqual(game.response?.kind, 'harkonnenTraitor');
+});
+
+void test('a Medium Harkonnen bot offers a legal allied group traitor call', () => {
+  const {game} = source('f');
+  const view = viewGame(game, 'h');
+  view.players.find(seat => seat.id === 'h')!.bot = 'Medium';
+  const action = botActions(view).find(candidate => candidate.type === 'traitorCall');
+  assert.ok(action); assert.equal(action.call, true);
+  assert.equal(send(game, 'h', action).response?.kind, 'harkonnenTraitor');
+});
+
+void test('the actual group table gives Harkonnen an enabled allied call without revealing its hand to the other ally', () => {
+  const {game, opponentLeader} = source('e');
+  const own = viewGame(game, 'h');
+  const ownMarkup = renderToStaticMarkup(createElement(GameTable, {
+    game:own, busy:false, send:async () => {}, onExit() {},
+  }));
+  const button = ownMarkup.match(/<button\b[^>]*>(?:(?!<\/button>)[\s\S])*Reveal ally’s opponent as traitor(?:(?!<\/button>)[\s\S])*<\/button>/)?.[0];
+  assert.ok(button, 'The allied call is offered to Harkonnen.');
+  assert.doesNotMatch(button, /\bdisabled(?:=|\s|>)/);
+  assert.ok(own.players.find(seat => seat.id === 'h')?.traitors?.includes(opponentLeader));
+  const observer = viewGame(game, 'f');
+  assert.equal(observer.players.find(seat => seat.id === 'h')?.traitors, undefined);
+  const observerMarkup = renderToStaticMarkup(createElement(GameTable, {
+    game:observer, busy:false, send:async () => {}, onExit() {},
+  }));
+  assert.doesNotMatch(observerMarkup, /Reveal ally’s opponent as traitor/);
+});

tests/coalition-traitor-declarations.test.ts

@@ -0,0 +1,95 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { coalitionOf, emptyCoalitionState } from '../game/coalition-alliance';
+import { applyAction, createGame, newPlayer } from '../game/engine';
+import { createTraitorDeclaration, validateTraitorDeclaration, validateTraitorDeclarations,
+  type TraitorDeclarationContext } from '../game/traitor-declarations';
+
+/** The ledger is staged because the lobby does not yet expose group play.
+ * Pair formation and unanimous admission use real Nexus actions. The battle
+ * plans and Harkonnen's known identity are staged for this receipt quote. */
+function source(group = true): TraitorDeclarationContext {
+  let game = createGame('GROUPTRAITOR', newPlayer('h', 'Harkonnen', 'harkonnen'), false);
+  game.players.push(newPlayer('a', 'Atreides', 'atreides'),
+    newPlayer('e', 'Emperor', 'emperor'), newPlayer('g', 'Guild', 'guild'));
+  Object.assign(game, {status:'playing', phase:1, turn:2, nexus:true,
+    order:['h','a','e','g'], ready:[], storm:18, response:null, decision:null, phaseOpening:null});
+  game.coalitionState = emptyCoalitionState();
+  game = applyAction(game, 'h', {type:'alliance', target:'a'});
+  game = applyAction(game, 'a', {type:'alliance', target:'h'});
+  if (group) {
+    const pair = coalitionOf(game.players, game.coalitionState, 'h'); assert.ok(pair);
+    game = applyAction(game, 'h', {type:'coalitionPropose', groupId:pair.id, entrant:'e',
+      expectedRevision:game.coalitionState!.revision});
+    for (const id of ['a','e']) {
+      const proposal = game.coalitionState!.proposal!;
+      game = applyAction(game, id, {type:'coalitionAnswer', event:proposal.event, nexus:proposal.nexus,
+        turn:proposal.turn, accept:true, expectedRevision:game.coalitionState!.revision});
+    }
+    assert.deepEqual(coalitionOf(game.players, game.coalitionState, 'h')!.members, ['a','e','h']);
+  }
+  return {event:'group-battle', attacker:'a', defender:'g',
+    status:'playing', advanced:false, expansions:[], coalitionState:game.coalitionState,
+    plans:{a:{leader:'a-leader'}, e:{leader:'e-leader'}, g:{leader:'g-leader'}},
+    players:game.players.map(player => ({id:player.id, faction:player.faction, ally:player.ally,
+      ...(player.allySinceTurn === undefined ? {} : {allySinceTurn:player.allySinceTurn}),
+      traitors:player.id === 'h' ? ['g-leader'] : []})), heroLeaderIds:[]};
+}
+
+void test('a Harkonnen group declaration binds each actual ally, opponent and identity', () => {
+  for (const ally of ['a','e']) {
+    const game = source();
+    game.attacker = ally;
+    const before = structuredClone(game);
+    const receipt = createTraitorDeclaration(game, 'h');
+    assert.deepEqual({voter:receipt.voter, beneficiary:receipt.beneficiary, target:receipt.target,
+      leader:receipt.leader, identity:receipt.identity},
+      {voter:'h', beneficiary:ally, target:'g', leader:'g-leader', identity:'g-leader'});
+    validateTraitorDeclaration(game, receipt);
+    validateTraitorDeclarations(game, {h:true}, {h:receipt}, 1);
+    assert.deepEqual(game, before);
+  }
+});
+
+void test('a group declaration rejects retargeted battle, leader, identity and receipt', () => {
+  const game = source();
+  const receipt = createTraitorDeclaration(game, 'h');
+  for (const mutate of [
+    (value: TraitorDeclarationContext) => { value.attacker = 'e'; },
+    (value: TraitorDeclarationContext) => { value.defender = 'e'; },
+    (value: TraitorDeclarationContext) => { value.plans.g.leader = 'replacement'; },
+    (value: TraitorDeclarationContext) => { value.plans.g.kwisatz = true; },
+    (value: TraitorDeclarationContext) => { value.event = 'another-battle'; },
+  ]) {
+    const changed = structuredClone(game);
+    mutate(changed);
+    assert.throws(() => validateTraitorDeclaration(changed, receipt));
+  }
+  for (const field of ['beneficiary','target','leader','identity','signature'] as const) {
+    const changed = {...receipt, [field]:'incorrect'};
+    assert.throws(() => validateTraitorDeclaration(game, changed));
+  }
+  const noIdentity = structuredClone(game);
+  noIdentity.players.find(player => player.id === 'h')!.traitors = [];
+  assert.throws(() => createTraitorDeclaration(noIdentity, 'h'));
+  validateTraitorDeclaration(noIdentity, receipt);
+});
+
+void test('group declaration is unavailable in unsupported profiles or ambiguous group battles', () => {
+  const game = source();
+  for (const patch of [{advanced:true}, {expansions:['ix']}, {homeworlds:{}},
+    {nexusCards:{}}, {leaderSkills:{}}, {techTokens:{}}, {strongholdCards:{}},
+    {ecazTreachery:true}, {discoveryEnabled:true}]) {
+    assert.throws(() => createTraitorDeclaration({...game, ...patch}, 'h'));
+  }
+  const ambiguous = {...game, defender:'e'};
+  assert.throws(() => createTraitorDeclaration(ambiguous, 'h'));
+});
+
+void test('the legacy Harkonnen pair retains implicit allied beneficiary', () => {
+  const game = source(false);
+  const receipt = createTraitorDeclaration(game, 'h');
+  assert.equal(receipt.beneficiary, 'a');
+  assert.equal(receipt.target, 'g');
+  validateTraitorDeclaration(game, receipt);
+});