fix(sessions): clear stale top-level spawn lineage

pfrederiksen · pfrederiksen · commit 99eb96710c38 · 2026-05-30T02:46:47.000Z
diff --git a/src/agents/agent-command.live-model-switch.test.ts b/src/agents/agent-command.live-model-switch.test.ts
@@ -264,6 +264,7 @@ vi.mock("../routing/session-key.js", async () => {
   );
   return {
     ...actual,
+    isAcpSessionKey: () => false,
     isSubagentSessionKey: () => false,
     normalizeAgentId: (id: string) => id,
     normalizeMainKey: (key?: string | null) => key?.trim() || "main",
@@ -1197,6 +1198,33 @@ describe("agentCommand – LiveSessionModelSwitchError retry", () => {
     expect(lifecycleFinishingCalls).toHaveLength(1);
   });
 
+  it("does not pass stale sessionEntry.spawnedBy for top-level sessions", async () => {
+    const runAttemptCalls: Array<{ spawnedBy?: string }> = [];
+    state.runWithModelFallbackMock.mockImplementation(async (params: FallbackRunnerParams) => {
+      const result = await params.run(params.provider, params.model);
+      return {
+        result,
+        provider: params.provider,
+        model: params.model,
+        attempts: [],
+      };
+    });
+    state.runAgentAttemptMock.mockImplementation(async (...args: unknown[]) => {
+      const attemptParams = args[0] as { spawnedBy?: string } | undefined;
+      runAttemptCalls.push({ spawnedBy: attemptParams?.spawnedBy });
+      return makeSuccessResult("anthropic", "claude");
+    });
+    state.sessionEntryMock = {
+      sessionId: "session-1",
+      updatedAt: Date.now(),
+      spawnedBy: "agent:main:subagent:stale-child",
+    };
+
+    await runBasicAgentCommand();
+
+    expect(runAttemptCalls[0]?.spawnedBy).toBeUndefined();
+  });
+
   it("validates explicit thinking against configured model compat without an allowlist", async () => {
     state.runtimeConfigMock = {
       agents: {
diff --git a/src/agents/agent-command.ts b/src/agents/agent-command.ts
@@ -26,6 +26,7 @@ import { createSubsystemLogger } from "../logging/subsystem.js";
 import { loadManifestMetadataSnapshot } from "../plugins/manifest-contract-eligibility.js";
 import {
   classifySessionKeyShape,
+  isAcpSessionKey,
   isUnscopedSessionKeySentinel,
   isSubagentSessionKey,
   normalizeAgentId,
@@ -1321,7 +1322,11 @@ async function agentCommandInternal(
     });
     for (;;) {
       try {
-        const spawnedBy = normalizedSpawned.spawnedBy ?? sessionEntry?.spawnedBy;
+        const spawnedBy =
+          normalizedSpawned.spawnedBy ??
+          (isSubagentSessionKey(sessionKey) || isAcpSessionKey(sessionKey)
+            ? sessionEntry?.spawnedBy
+            : undefined);
         const effectiveFallbacksOverride = resolveEffectiveModelFallbacks({
           cfg,
           agentId: sessionAgentId,
diff --git a/src/auto-reply/reply/session.ts b/src/auto-reply/reply/session.ts
@@ -43,7 +43,11 @@ import { createSubsystemLogger } from "../../logging/subsystem.js";
 import { closeTrackedBrowserTabsForSessions } from "../../plugin-sdk/browser-maintenance.js";
 import { getGlobalHookRunner } from "../../plugins/hook-runner-global.js";
 import type { PluginHookSessionEndReason } from "../../plugins/hook-types.js";
-import { isAcpSessionKey, normalizeMainKey } from "../../routing/session-key.js";
+import {
+  isAcpSessionKey,
+  isSubagentSessionKey,
+  normalizeMainKey,
+} from "../../routing/session-key.js";
 import { isInterSessionInputProvenance } from "../../sessions/input-provenance.js";
 import { createLazyImportLoader } from "../../shared/lazy-promise.js";
 import {
@@ -628,6 +632,7 @@ export async function initSessionState(params: {
   const lastTo = deliveryFields.lastTo ?? lastToRaw;
   const lastAccountId = deliveryFields.lastAccountId ?? lastAccountIdRaw;
   const lastThreadId = deliveryFields.lastThreadId ?? lastThreadIdRaw;
+  const preserveSpawnLineage = isSubagentSessionKey(sessionKey) || isAcpSessionKey(sessionKey);
   sessionEntry = {
     ...baseEntry,
     sessionId,
@@ -659,14 +664,20 @@ export async function initSessionState(params: {
     cliSessionBindings: baseEntry?.cliSessionBindings,
     claudeCliSessionId: baseEntry?.claudeCliSessionId,
     label: persistedLabel ?? baseEntry?.label,
-    spawnedBy: persistedSpawnedBy ?? baseEntry?.spawnedBy,
-    spawnedWorkspaceDir: persistedSpawnedWorkspaceDir ?? baseEntry?.spawnedWorkspaceDir,
-    spawnedCwd: persistedSpawnedCwd ?? baseEntry?.spawnedCwd,
+    spawnedBy: preserveSpawnLineage ? (persistedSpawnedBy ?? baseEntry?.spawnedBy) : undefined,
+    spawnedWorkspaceDir: preserveSpawnLineage
+      ? (persistedSpawnedWorkspaceDir ?? baseEntry?.spawnedWorkspaceDir)
+      : undefined,
+    spawnedCwd: preserveSpawnLineage ? (persistedSpawnedCwd ?? baseEntry?.spawnedCwd) : undefined,
     parentSessionKey: persistedParentSessionKey ?? baseEntry?.parentSessionKey,
     forkedFromParent: persistedForkedFromParent ?? baseEntry?.forkedFromParent,
-    spawnDepth: persistedSpawnDepth ?? baseEntry?.spawnDepth,
-    subagentRole: persistedSubagentRole ?? baseEntry?.subagentRole,
-    subagentControlScope: persistedSubagentControlScope ?? baseEntry?.subagentControlScope,
+    spawnDepth: preserveSpawnLineage ? (persistedSpawnDepth ?? baseEntry?.spawnDepth) : undefined,
+    subagentRole: preserveSpawnLineage
+      ? (persistedSubagentRole ?? baseEntry?.subagentRole)
+      : undefined,
+    subagentControlScope: preserveSpawnLineage
+      ? (persistedSubagentControlScope ?? baseEntry?.subagentControlScope)
+      : undefined,
     sendPolicy: baseEntry?.sendPolicy,
     queueMode: baseEntry?.queueMode,
     queueDebounceMs: baseEntry?.queueDebounceMs,
