feat(memory): add shared history context to social narration prompts

When narrating social interactions, the LLM now receives up to 3 shared
history events between the two NPCs, enabling more contextual narrations
that reference past encounters.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/llm/__tests__/narrationService.test.ts

@@ -205,6 +205,7 @@ describe('NarrationService', () => {
       outcome: 'negative',
       relationship: 'rival',
       sentiment: '-0.3',
+      recentHistory: '',
     });
   });
 });

server/src/llm/narrationService.ts

@@ -13,6 +13,7 @@ export interface InteractionRecord {
   npc1Personality?: string;
   npc2Personality?: string;
   sentiment?: number;
+  sharedHistory?: string;
 }
 
 export interface NarrationService {
@@ -69,6 +70,7 @@ export function createNarrationService(llmService: LlmService): NarrationService
           outcome: record.outcome,
           relationship: record.classification,
           sentiment: String(record.sentiment ?? ''),
+          recentHistory: record.sharedHistory ?? '',
         };
 
         llmService.generate('socialNarration', variables).then((result) => {

server/src/llm/templates.ts

@@ -27,6 +27,7 @@ export const templates: Record<string, PromptTemplate> = {
       '{{npc1Name}} ({{npc1Personality}}) had a {{outcome}} interaction with ' +
       '{{npc2Name}} ({{npc2Personality}}). ' +
       'They are currently {{relationship}} (sentiment: {{sentiment}}/100).\n' +
+      'Their recent shared history:\n{{recentHistory}}\n' +
       'Describe what happened in one vivid sentence.',
   },
 

server/src/systems/narrationEmitter.ts

@@ -5,11 +5,13 @@ import type { World } from '../ecs/World.js';
 import type { NarrationService } from '../llm/narrationService.js';
 import { formatStatsForPrompt } from '../llm/backstoryGenerator.js';
 import { classify } from './relationshipHelpers.js';
+import type { EventMemoryService } from '../llm/eventMemoryService.js';
 
 export function narrationEmitter(
   world: World,
   narrationService: NarrationService,
   followedEntityIds: Set<EntityId>,
+  eventMemoryService?: EventMemoryService,
 ): void {
   const entities = world.query('socialState', 'name', 'stats');
   const processed = new Set<string>();
@@ -69,6 +71,18 @@ export function narrationEmitter(
     const [firstName, secondName] = entity < partnerId ? [name1, name2] : [name2, name1];
     const [firstStats, secondStats] = entity < partnerId ? [stats1, stats2] : [stats2, stats1];
 
+    let sharedHistory = '';
+    if (eventMemoryService) {
+      const events = eventMemoryService.selectForPrompt(firstId, {
+        maxCount: 3,
+        preferEntityId: secondId,
+        preferTypes: ['social_positive', 'social_negative', 'tier_change'],
+      });
+      if (events.length > 0) {
+        sharedHistory = events.map(e => `- ${e.detail}`).join('\n');
+      }
+    }
+
     narrationService.recordInteraction({
       tick: social.lastOutcome.tick,
       entityIds: [firstId, secondId],
@@ -80,6 +94,7 @@ export function narrationEmitter(
       npc1Personality: firstStats ? formatStatsForPrompt(firstStats) : undefined,
       npc2Personality: secondStats ? formatStatsForPrompt(secondStats) : undefined,
       sentiment: relValue,
+      sharedHistory,
     });
   }
 }