fix(transcript): project only a fork's own turns into its transcript

.changeset/fork-transcript-own-turns.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fix /btw side-chat transcripts showing inherited main-conversation turns with mismatched prompts and answers.

packages/agent-core-v2/docs/state-manifest.d.ts

@@ -1241,6 +1241,7 @@ export interface AgentStateSnapshot {
       detail?: unknown;
     }>;
     readonly note?: string;
+    readonly inherited?: boolean;
   })[];
   // src/agent/contextProjector/contextProjectorService.ts
   'contextProjector.lastRepairSignature': string | null;

packages/agent-core-v2/docs/wire-manifest.d.ts

@@ -140,6 +140,7 @@ interface ContextAppendMessagePayload {
     isError?: boolean;
     toolCallDisplays?: Record<string, ToolInputDisplay>;
     note?: string;
+    inherited?: boolean;
   };
 }
 

packages/agent-core-v2/src/agent/contextMemory/contextTranscript.ts

@@ -30,6 +30,7 @@ interface MutableMessage {
   isError?: boolean;
   note?: string;
   origin?: ContextMessage['origin'];
+  inherited?: boolean;
 }
 
 interface MutableEntry {
@@ -175,6 +176,7 @@ function toMutableEntry(message: ContextMessage, time: number | undefined): Muta
       ...(message.toolCallId !== undefined ? { toolCallId: message.toolCallId } : {}),
       ...(message.isError !== undefined ? { isError: message.isError } : {}),
       ...(message.origin !== undefined ? { origin: message.origin } : {}),
+      inherited: message.inherited,
     },
     time,
   };

packages/agent-core-v2/src/agent/contextMemory/types.ts

@@ -126,6 +126,7 @@ export type ContextMessage = Message & {
   readonly isError?: boolean;
   toolCallDisplays?: Record<string, ToolInputDisplay>;
   readonly note?: string;
+  readonly inherited?: boolean;
 };
 
 export interface UserMessageRecord {

packages/agent-core-v2/src/session/agentLifecycle/agentLifecycleService.ts

@@ -320,9 +320,11 @@ export class AgentLifecycleService extends Disposable implements IAgentLifecycle
 
     const sourceMessages = source.accessor.get(IAgentContextMemoryService)?.get();
     if (sourceMessages !== undefined && sourceMessages.length > 0) {
-      child.accessor
-        .get(IAgentContextMemoryService)
-        ?.append(...closeTrailingOpenToolExchange(sourceMessages));
+      const inherited = closeTrailingOpenToolExchange(sourceMessages).map((message) => ({
+        ...message,
+        inherited: true,
+      }));
+      child.accessor.get(IAgentContextMemoryService)?.append(...inherited);
     }
     return childContext;
   }

packages/agent-core-v2/test/session/agentLifecycle/agentLifecycle.test.ts

@@ -1258,6 +1258,29 @@ describe('AgentLifecycleService', () => {
     });
   });
 
+  it('fork marks the seeded context messages as inherited without touching the source', async () => {
+    const svc = ix.get(IAgentLifecycleService);
+    const source = await svc.create({ agentId: 'main' });
+    const sourceHandle = svc.handleOf('main')!;
+    const history: ContextMessage[] = [
+      { role: 'user', content: [{ type: 'text', text: 'analyze this repo' }], toolCalls: [] },
+      { role: 'assistant', content: [{ type: 'text', text: 'done' }], toolCalls: [] },
+    ];
+    sourceHandle.accessor.get(IAgentContextMemoryService).append(...history);
+
+    const child = await svc.fork(agentContextOf(sourceHandle), { agentId: 'forked' });
+
+    const seeded = svc.handleOf(child.agentId)!.accessor.get(IAgentContextMemoryService).get();
+    expect(seeded).toHaveLength(2);
+    expect(seeded.every((message) => message.inherited === true)).toBe(true);
+    expect(
+      sourceHandle.accessor
+        .get(IAgentContextMemoryService)
+        .get()
+        .every((message) => message.inherited === undefined),
+    ).toBe(true);
+  });
+
   it('fork leaves the child context empty when the source history is empty', async () => {
     const svc = ix.get(IAgentLifecycleService);
     const source = await svc.create({ agentId: 'main' });

packages/kap-server/src/services/transcript/transcriptService.ts

@@ -425,19 +425,26 @@ export class TranscriptService {
   async readColdRoster(sessionId: string): Promise<AgentDescriptor[] | undefined> {
     const summary = await this.deps.core.accessor.get(ISessionIndex).get(sessionId);
     if (summary === undefined) return undefined;
-    let meta: SessionMeta;
+    const meta = await this.readSessionMeta(summary.workspaceId, sessionId);
+    if (meta === undefined) return [];
+    return Object.entries(meta.agents ?? {}).map(([agentId, agentMeta]) =>
+      descriptorFromMeta(agentId, agentMeta),
+    );
+  }
+
+  private async readSessionMeta(
+    workspaceId: string,
+    sessionId: string,
+  ): Promise<SessionMeta | undefined> {
     try {
       const raw = await readFile(
-        join(this.deps.homeDir, SESSIONS_ROOT, summary.workspaceId, sessionId, STATE_FILE),
+        join(this.deps.homeDir, SESSIONS_ROOT, workspaceId, sessionId, STATE_FILE),
         'utf-8',
       );
-      meta = JSON.parse(raw) as SessionMeta;
+      return JSON.parse(raw) as SessionMeta;
     } catch {
-      return [];
+      return undefined;
     }
-    return Object.entries(meta.agents ?? {}).map(([agentId, agentMeta]) =>
-      descriptorFromMeta(agentId, agentMeta),
-    );
   }
 
   async readColdSnapshot(
@@ -467,13 +474,20 @@ export class TranscriptService {
       }
       throw error;
     }
-    const messages = [...reduceContextTranscript(records).entries];
+    const meta = await this.readSessionMeta(summary.workspaceId, sessionId);
+    const forkedFrom = meta?.agents?.[agentId]?.forkedFrom;
+    const projectionRecords = stripLegacyInheritedRecords(records, forkedFrom);
+    const messages = [...reduceContextTranscript(projectionRecords).entries].filter(
+      (message) =>
+        message.inherited !== true &&
+        (forkedFrom === undefined || message.origin?.kind !== 'compaction_summary'),
+    );
     const taskOriginTurnTaskIds = new Set<string>();
     const steeredContents = new Map<string, Map<string, number>>();
     const anchorStack: { taskIdsSnapshot: Set<string> }[] = [];
     let anchorFloor = 0;
     let sawTurnPrompt = false;
-    for (const record of records) {
+    for (const record of projectionRecords) {
       if (record.type === 'context.undo') {
         const count = typeof record['count'] === 'number' ? (record['count'] as number) : 0;
         for (let i = 0; i < count && anchorStack.length > anchorFloor; i++) {
@@ -521,7 +535,7 @@ export class TranscriptService {
       messages,
       sawTurnPrompt || steeredContents.size > 0 ? { taskOriginTurnTaskIds, steeredContents } : undefined,
     );
-    const folded = foldWireRecordFacts(projectQuestionInteractionRecords(records, sessionId), base, {
+    const folded = foldWireRecordFacts(projectQuestionInteractionRecords(projectionRecords, sessionId), base, {
       resolvePlanRevisionKey: (key) =>
         join(SESSIONS_ROOT, summary.workspaceId, sessionId, AGENTS_DIR, agentId, key),
     });
@@ -629,6 +643,24 @@ const TERMINAL_TURN_STATES: ReadonlySet<TranscriptTurn['state']> = new Set([
   'cancelled',
 ]);
 
+function stripLegacyInheritedRecords(
+  records: readonly ContextRecord[],
+  forkedFrom: string | undefined,
+): readonly ContextRecord[] {
+  if (forkedFrom === undefined) return records;
+  const marked = records.some(
+    (record) =>
+      record.type === 'context.append_message' &&
+      (record as { message?: ContextMessage }).message?.inherited === true,
+  );
+  if (marked) return records;
+  const firstPrompt = records.findIndex((record) => record.type === 'turn.prompt');
+  const cutoff = firstPrompt === -1 ? records.length : firstPrompt;
+  return records.filter(
+    (record, index) => index >= cutoff || record.type !== 'context.append_message',
+  );
+}
+
 function projectQuestionInteractionRecords(
   records: readonly ContextRecord[],
   sessionId: string,