feat(pi): retain terminal subagent work

modules/agents/pi/extensions/subagents/index.ts

@@ -106,7 +106,7 @@ export default function subagents(pi: ExtensionAPI) {
   pi.registerTool({
     name: "subagent_list",
     label: "List subagents",
-    description: "List active and recent subagents for this parent session",
+    description: "List active and terminal subagents for this parent session until terminal entries are cleared",
     parameters: Type.Object({}),
     async execute(_toolCallId, _params, _signal, _onUpdate, ctx) {
       return textResult(getSupervisor(ctx).list());
@@ -167,6 +167,20 @@ export default function subagents(pi: ExtensionAPI) {
     },
   });
 
+  pi.registerTool({
+    name: "subagent_clear",
+    label: "Clear terminal subagents",
+    description: "Remove terminal subagents from the current-session visible work set. Omitting ids clears all terminal children",
+    parameters: Type.Object({
+      ids: Type.Optional(Type.Array(Type.String({ description: "Subagent id returned by subagent_spawn or subagent_batch" }))),
+    }),
+    async execute(_toolCallId, params, _signal, _onUpdate, ctx) {
+      const input = params as { ids?: unknown };
+      const ids = Array.isArray(input.ids) ? input.ids.map(String) : undefined;
+      return textResult({ cleared: getSupervisor(ctx).clearTerminal(ids) });
+    },
+  });
+
   pi.registerCommand("subagent-spawn", {
     description: "Start an ad hoc independent subagent",
     handler: async (args, ctx) => {
@@ -194,6 +208,14 @@ export default function subagents(pi: ExtensionAPI) {
     },
   });
 
+  pi.registerCommand("subagent-clear", {
+    description: "Clear terminal subagent records. Pass ids to clear selected terminal records only",
+    handler: async (args, ctx) => {
+      const ids = args.trim().split(/\s+/u).filter(Boolean);
+      ctx.ui.notify(JSON.stringify({ cleared: getSupervisor(ctx).clearTerminal(ids.length > 0 ? ids : undefined) }, null, 2), "info");
+    },
+  });
+
   pi.registerCommand("subagent-status", {
     description: "Show a subagent status by id",
     handler: async (args, ctx) => {

modules/agents/pi/extensions/subagents/supervisor.test.ts

@@ -236,58 +236,42 @@ test("maxConcurrent preserves queued records", async () => {
   assert.equal(runner.starts.length, 2);
 });
 
-test("recent terminal statuses expire from list by ttl", async () => {
+test("terminal records stay listed past ttl and remain retrievable until cleared", async () => {
   const runner = new FakeRunner();
   const supervisor = new Supervisor(runner, "/tmp", { recentTerminalTtlMs: 5 });
-  const accepted = await spawnStarted(supervisor);
+  const completed = await spawnStarted(supervisor, "one");
-
+  const failed = await spawnStarted(supervisor, "two");
-  runner.starts[0].events.completed("done", "agent_settled");
-  assert.equal(supervisor.list().some((status) => status.id === accepted.id), true);
 
+  runner.starts[0].events.completed("one done", "agent_settled");
+  runner.starts[1].events.failed("two failed");
   await sleep(10);
 
-  assert.equal(supervisor.list().some((status) => status.id === accepted.id), false);
+  const listedIds = supervisor.list().map((status) => status.id);
-  assert.equal(supervisor.result(accepted.id).result, "done");
+  assert.ok(listedIds.includes(completed.id));
+  assert.ok(listedIds.includes(failed.id));
+  assert.equal(supervisor.result(completed.id).result, "one done");
+  assert.equal(supervisor.result(failed.id).error, "two failed");
+
+  (supervisor as Supervisor & { clearTerminal(): void }).clearTerminal();
+
+  const afterClearIds = supervisor.list().map((status) => status.id);
+  assert.equal(afterClearIds.includes(completed.id), false);
+  assert.equal(afterClearIds.includes(failed.id), false);
+  assert.throws(() => supervisor.status(completed.id), /unknown subagent id/);
+  assert.throws(() => supervisor.result(failed.id), /unknown subagent id/);
 });
 
-test("recent terminal ttl does not hide active statuses", async () => {
+test("zero recent terminal ttl does not hide terminal statuses", async () => {
   const runner = new FakeRunner();
   const supervisor = new Supervisor(runner, "/tmp", { recentTerminalTtlMs: 0 });
   const accepted = await spawnStarted(supervisor);
 
+  runner.starts[0].events.completed("done", "agent_settled");
+
   assert.equal(supervisor.list().some((status) => status.id === accepted.id), true);
-});
-
-test("zero recent terminal ttl hides terminal statuses immediately", async () => {
-  const runner = new FakeRunner();
-  const supervisor = new Supervisor(runner, "/tmp", { recentTerminalTtlMs: 0 });
-  const accepted = await spawnStarted(supervisor);
-
-  runner.starts[0].events.completed("done", "agent_settled");
-
-  assert.equal(supervisor.list().some((status) => status.id === accepted.id), false);
   assert.equal(supervisor.result(accepted.id).result, "done");
 });
 
-test("recent terminal ttl emits a change when an entry expires", async () => {
-  const runner = new FakeRunner();
-  let changes = 0;
-  const supervisor = new Supervisor(runner, "/tmp", {
-    recentTerminalTtlMs: 5,
-    onChange: () => {
-      changes += 1;
-    },
-  });
-  await spawnStarted(supervisor);
-  const beforeComplete = changes;
-
-  runner.starts[0].events.completed("done", "agent_settled");
-  await sleep(15);
-
-  assert.ok(changes > beforeComplete + 1);
-  assert.equal(supervisor.list().length, 0);
-});
-
 test("wait blocks until multiple subagents are terminal", async () => {
   const runner = new FakeRunner();
   const supervisor = new Supervisor(runner, "/tmp");

modules/agents/pi/extensions/subagents/supervisor.ts

@@ -48,7 +48,6 @@ export class Supervisor {
   private readonly children = new Map<string, RunningChild>();
   private readonly queue: RunningChild[] = [];
   private readonly waiters = new Set<() => void>();
-  private recentTerminalTimer?: ReturnType<typeof setTimeout>;
 
   constructor(
     private readonly runner: ChildRunner,
@@ -78,9 +77,7 @@ export class Supervisor {
     const active = statuses.filter((status) => !isTerminal(status.state));
     const terminal = statuses
       .filter((status) => isTerminal(status.state))
-      .filter((status) => this.isRecentTerminal(status))
+      .sort((a, b) => Date.parse(b.completedAt ?? b.startedAt) - Date.parse(a.completedAt ?? a.startedAt));
-      .sort((a, b) => Date.parse(b.completedAt ?? b.startedAt) - Date.parse(a.completedAt ?? a.startedAt))
-      .slice(0, this.options.recentTerminalLimit ?? 10);
     return [...active, ...terminal];
   }
 
@@ -92,6 +89,20 @@ export class Supervisor {
     return cloneResult(this.require(id).record);
   }
 
+  clearTerminal(ids?: string[]): SubagentStatus[] {
+    const selectedIds = ids ? [...new Set(ids.map((id) => id.trim()).filter(Boolean))] : undefined;
+    if (selectedIds) for (const id of selectedIds) this.require(id);
+    const cleared: SubagentStatus[] = [];
+    for (const [id, child] of this.children) {
+      if (selectedIds && !selectedIds.includes(id)) continue;
+      if (!isTerminal(child.record.status.state)) continue;
+      cleared.push(cloneStatus(child.record.status));
+      this.children.delete(id);
+    }
+    if (cleared.length > 0) this.emitChange();
+    return cleared;
+  }
+
   async wait(
     ids: string[],
     options: { timeoutMs?: number; signal?: AbortSignal; mode?: SubagentWaitMode } = {},
@@ -137,7 +148,6 @@ export class Supervisor {
   }
 
   async shutdown(): Promise<void> {
-    this.clearRecentTerminalTimer();
     await Promise.allSettled(
       [...this.children.values()].map(async (child) => {
         if (!isTerminal(child.record.status.state)) {
@@ -146,7 +156,6 @@ export class Supervisor {
         }
       }),
     );
-    this.clearRecentTerminalTimer();
   }
 
   private createChild(request: SpawnRequest): SpawnAccepted {
@@ -345,39 +354,6 @@ export class Supervisor {
   private emitChange() {
     this.options.onChange?.(this.list());
     for (const waiter of this.waiters) waiter();
-    this.scheduleRecentTerminalExpiry();
-  }
-
-  private scheduleRecentTerminalExpiry() {
-    this.clearRecentTerminalTimer();
-    const ttl = this.options.recentTerminalTtlMs;
-    if (ttl === undefined || ttl <= 0) return;
-    const now = Date.now();
-    const nextExpiryMs = [...this.children.values()]
-      .map((child) => child.record.status)
-      .filter((status) => isTerminal(status.state))
-      .map((status) => Date.parse(status.completedAt ?? status.startedAt))
-      .filter((completed) => Number.isFinite(completed))
-      .map((completed) => completed + ttl - now)
-      .filter((remaining) => remaining > 0)
-      .sort((a, b) => a - b)[0];
-    if (nextExpiryMs === undefined) return;
-    this.recentTerminalTimer = setTimeout(() => this.emitChange(), nextExpiryMs + 1);
-  }
-
-  private clearRecentTerminalTimer() {
-    if (!this.recentTerminalTimer) return;
-    clearTimeout(this.recentTerminalTimer);
-    this.recentTerminalTimer = undefined;
-  }
-
-  private isRecentTerminal(status: SubagentStatus): boolean {
-    const ttl = this.options.recentTerminalTtlMs;
-    if (ttl === undefined) return true;
-    if (ttl <= 0) return false;
-    const completed = Date.parse(status.completedAt ?? status.startedAt);
-    if (!Number.isFinite(completed)) return true;
-    return Date.now() - completed <= ttl;
   }
 
   private waitReady(ids: string[], mode: SubagentWaitMode): boolean {

modules/agents/pi/extensions/subagents/ui.ts

@@ -6,7 +6,7 @@ export function renderSummary(statuses: SubagentStatus[]): string[] {
   const queued = statuses.filter((status) => status.state === "queued").length;
   const terminal = statuses.filter((status) => isTerminalState(status.state)).length;
   if (running === 0 && queued === 0 && terminal === 0) return [];
-  return [`subagents: ${running} running · ${queued} queued · ${terminal} recent`];
+  return [`subagents: ${running} running · ${queued} queued · ${terminal} terminal`];
 }
 
 export function renderInspector(statuses: SubagentStatus[]): string[] {