fix(subagents): retain history across hydration

packages/server/src/server/agent/agent-manager.test.ts

@@ -2885,6 +2885,11 @@ test("archiveFinishedSubagents archives managed children and keeps dismissed pro
       workspaceId: undefined,
     },
   );
+  const managedWithRunningProviderDescendant = await manager.createAgent(
+    { provider: "codex", cwd: workdir },
+    undefined,
+    { labels: { [PARENT_AGENT_ID_LABEL]: parent.id }, workspaceId: undefined },
+  );
   client.sessions[3]?.pushEvent({
     type: "turn_started",
     provider: "codex",
@@ -2893,6 +2898,19 @@ test("archiveFinishedSubagents archives managed children and keeps dismissed pro
   await vi.waitFor(() => {
     expect(manager.getAgent(runningGrandchild.id)?.lifecycle).toBe("running");
   });
+  client.sessions[4]?.pushEvent({
+    type: "provider_subagent",
+    provider: "codex",
+    event: { type: "upsert", id: "running-provider-grandchild", status: "running" },
+  });
+  await vi.waitFor(() => {
+    expect(
+      manager.getProviderSubagent(
+        managedWithRunningProviderDescendant.id,
+        "running-provider-grandchild",
+      )?.status,
+    ).toBe("running");
+  });
   await manager.hydrateTimelineFromProvider(parent.id);
 
   const result = await manager.archiveFinishedSubagents(parent.id);
@@ -2903,6 +2921,7 @@ test("archiveFinishedSubagents archives managed children and keeps dismissed pro
   });
   expectArchivedAgentRecord(await storage.get(managedFinished.id), "closed");
   expect((await storage.get(managedWithRunningDescendant.id))?.archivedAt).toBeFalsy();
+  expect((await storage.get(managedWithRunningProviderDescendant.id))?.archivedAt).toBeFalsy();
   expect(manager.getAgent(runningGrandchild.id)?.lifecycle).toBe("running");
   expect(manager.listProviderSubagents(parent.id).map((subagent) => subagent.id)).toEqual([
     "native-running",
@@ -2927,6 +2946,11 @@ test("archiveFinishedSubagents archives managed children and keeps dismissed pro
   expect(manager.listProviderSubagents(parent.id).map((subagent) => subagent.id)).toEqual([
     "native-running",
   ]);
+  expect(manager.getProviderSubagent(parent.id, "native-finished")).toMatchObject({
+    id: "native-finished",
+    status: "completed",
+  });
+  expect(() => manager.fetchProviderSubagentTimeline(parent.id, "native-finished")).not.toThrow();
 });
 
 test("force provider hydration removes children absent from current history", async () => {

packages/server/src/server/agent/agent-manager.ts

@@ -985,6 +985,9 @@ export class AgentManager {
     const hasBusyDescendant = (agentId: string, visited = new Set<string>()): boolean => {
       if (visited.has(agentId)) return true;
       visited.add(agentId);
+      if (this.providerSubagents.list(agentId).some((subagent) => subagent.status === "running")) {
+        return true;
+      }
       for (const child of recordsByParentId.get(agentId) ?? []) {
         const liveChild = this.agents.get(child.id);
         if (
@@ -2980,8 +2983,9 @@ export class AgentManager {
   private applyProviderSubagentEvent(
     agent: ManagedAgent,
     event: Extract<AgentStreamEvent, { type: "provider_subagent" }>,
+    options?: { includeDismissed?: boolean },
   ): ProviderSubagentStoreEvent | null {
-    if (agent.dismissedProviderSubagentIds.has(event.event.id)) {
+    if (!options?.includeDismissed && agent.dismissedProviderSubagentIds.has(event.event.id)) {
       return null;
     }
     return this.providerSubagents.apply(agent.id, event.provider, event.event);
@@ -3120,12 +3124,18 @@ export class AgentManager {
 
     for (const event of this.providerSubagents.deleteParent(agent.id)) {
       if (broadcast) {
-        this.dispatch({ type: "provider_subagent", event });
+        this.dispatch({
+          type: "provider_subagent",
+          event: agent.dismissedProviderSubagentIds.has(event.subagentId)
+            ? { ...event, retainTimeline: true }
+            : event,
+        });
       }
     }
     for (const event of providerSubagentEvents) {
-      const update = this.applyProviderSubagentEvent(agent, event);
-      if (broadcast && update) {
+      const dismissed = agent.dismissedProviderSubagentIds.has(event.event.id);
+      const update = this.applyProviderSubagentEvent(agent, event, { includeDismissed: true });
+      if (broadcast && update && !dismissed) {
         this.dispatch({ type: "provider_subagent", event: update });
       }
     }

packages/server/src/server/agent/provider-subagents/store.ts

@@ -160,8 +160,8 @@ export class ProviderSubagentStore {
     };
   }
 
-  deleteParent(parentAgentId: string): ProviderSubagentStoreEvent[] {
-    const events: ProviderSubagentStoreEvent[] = [];
+  deleteParent(parentAgentId: string): Extract<ProviderSubagentStoreEvent, { type: "remove" }>[] {
+    const events: Extract<ProviderSubagentStoreEvent, { type: "remove" }>[] = [];
     for (const subagent of this.list(parentAgentId)) {
       const key = storeKey(parentAgentId, subagent.id);
       this.descriptors.delete(key);

packages/server/src/server/agent/providers/codex/tool-call-mapper.test.ts

@@ -246,7 +246,7 @@ describe("codex tool-call mapper", () => {
       detail: {
         type: "sub_agent",
         subAgentType: "research/investigator",
-        description: "/root/research/investigator",
+        description: "research/investigator",
         log: "",
         actions: [],
       },
@@ -280,7 +280,7 @@ describe("codex tool-call mapper", () => {
       detail: {
         type: "sub_agent",
         subAgentType: "investigator",
-        description: "/tmp/native/investigator",
+        description: "investigator",
       },
     });
   });
@@ -298,7 +298,7 @@ describe("codex tool-call mapper", () => {
       detail: {
         type: "sub_agent",
         subAgentType: "investigator",
-        description: "C:\\Users\\dev\\agents\\investigator",
+        description: "investigator",
       },
     });
   });

packages/server/src/server/agent/providers/codex/tool-call-mapper.ts

@@ -1003,6 +1003,7 @@ function mapSubAgentActivityItem(
       Math.max(nativeName.lastIndexOf("/"), nativeName.lastIndexOf("\\")) + 1,
     );
   }
+  const description = nativeName;
   nativeName ||= "Sub-agent";
   return {
     type: "tool_call",
@@ -1013,7 +1014,7 @@ function mapSubAgentActivityItem(
     detail: {
       type: "sub_agent",
       subAgentType: nativeName,
-      description: item.agentPath,
+      description,
       log: "",
       actions: [],
     },