diff --git a/packages/app/src/runtime/directory-sync/agent-replica.test.ts b/packages/app/src/runtime/directory-sync/agent-replica.test.ts
index 316e8e03bf..648c66c590 100644
--- a/packages/app/src/runtime/directory-sync/agent-replica.test.ts
+++ b/packages/app/src/runtime/directory-sync/agent-replica.test.ts
@@ -369,4 +369,25 @@ describe("AgentDirectoryReplica", () => {
     ).toEqual(directoryPlacement);
     store.clearSession(serverId);
   });
+
+  it("keeps a timeline-hydrated agent when a sequenced catch-up carries no entries", () => {
+    const serverId = "agent-replica-timeline-membership";
+    const store = useSessionStore.getState();
+    store.initializeSession(serverId, null as unknown as DaemonClient);
+    const replica = new AgentDirectoryReplica(
+      serverId,
+      () => undefined,
+      () => undefined,
+    );
+
+    // A conversation opened from history arrives over its timeline, without the
+    // project placement the directory carries, and is a member from then on.
+    replica.submitTimelineAgent(replica.captureTimeline("agent"), payload("timeline only"));
+    expect(useSessionStore.getState().sessions[serverId]?.agents.has("agent")).toBe(true);
+
+    replica.commitChanges([], [], []);
+
+    expect(useSessionStore.getState().sessions[serverId]?.agents.has("agent")).toBe(true);
+    store.clearSession(serverId);
+  });
 });
diff --git a/packages/app/src/runtime/directory-sync/agent-replica.ts b/packages/app/src/runtime/directory-sync/agent-replica.ts
index dac4ec5d28..37d5a1e4cb 100644
--- a/packages/app/src/runtime/directory-sync/agent-replica.ts
+++ b/packages/app/src/runtime/directory-sync/agent-replica.ts
@@ -6,15 +6,21 @@ import type { Agent } from "@/stores/session-store";
 import { normalizeAgentSnapshot, projectAgentSnapshot } from "@/utils/agent-snapshots";
 import { type AgentDirectoryDelta } from "@/utils/agent-directory-sync";
 import { reconcileAgentDirectory } from "@/utils/agent-directory-reconciliation";
+import { resolveProjectPlacement } from "@/utils/project-placement";
 import { applyLegacyDaemonWorkspaceOwnership } from "@/workspace/legacy-daemon-workspaces";
 import type { DirectoryReplicaMutation } from "@/runtime/replica-cache";
 import type { TurnLivenessTransition } from "@/timeline/turn-liveness";
 import { AgentStoreProjection } from "./internal/agent-store";
 
-function projectAgentDirectoryEntry(agent: Agent): FetchAgentsEntry | null {
-  return agent.projectPlacement
-    ? { agent: projectAgentSnapshot(agent), project: agent.projectPlacement }
-    : null;
+// A member hydrated from its timeline or restored from the replica cache carries
+// no placement. Every other path in this flow derives one from the working
+// directory, so this one does too; returning nothing here would drop the member
+// from the merged directory and delete the conversation on the next catch-up.
+function projectAgentDirectoryEntry(agent: Agent): FetchAgentsEntry {
+  return {
+    agent: projectAgentSnapshot(agent),
+    project: resolveProjectPlacement({ projectPlacement: agent.projectPlacement, cwd: agent.cwd }),
+  };
 }
 
 export interface AgentLifecycleToken {
@@ -164,8 +170,7 @@ export class AgentDirectoryReplica {
     const previous = this.storeProjection.snapshot();
     const merged = new Map<string, FetchAgentsEntry>();
     for (const agent of previous.values()) {
-      const entry = projectAgentDirectoryEntry(agent);
-      if (entry) merged.set(agent.id, entry);
+      merged.set(agent.id, projectAgentDirectoryEntry(agent));
     }
     for (const entry of entries) merged.set(entry.agent.id, entry);
     const removalsAsDeltas: AgentDirectoryDelta[] = removals.map(({ id }) => ({
diff --git a/packages/app/src/runtime/directory-sync/index.test.ts b/packages/app/src/runtime/directory-sync/index.test.ts
index 9f64a4fc60..ba8dc97b8e 100644
--- a/packages/app/src/runtime/directory-sync/index.test.ts
+++ b/packages/app/src/runtime/directory-sync/index.test.ts
@@ -640,6 +640,63 @@ describe("DirectorySync session readiness", () => {
     directory.dispose();
   });
 
+  it("reconciles agent changes on top of the accepted cached baseline", async () => {
+    const serverId = "cached-agent-changes";
+    serverIds.add(serverId);
+    const client = new FakeDirectoryClient();
+    const cachedAgent = createAgent(serverId, "cached-agent");
+    const releaseNetwork = client.holdAgentFetch();
+    const directory = new DirectorySync(
+      serverId,
+      {
+        onAgentStoppedRunning: () => undefined,
+        markAgentLoading: () => undefined,
+        markAgentReady: () => undefined,
+        markAgentError: () => undefined,
+      },
+      {
+        readAgent: async () => undefined,
+        readWorkspace: async () => undefined,
+        readDirectory: async () => ({
+          agents: new Map([[cachedAgent.id, cachedAgent]]),
+          workspaces: new Map(),
+          projects: new Map(),
+          checkpoint: { agents: { generation: "g", afterSeq: 7 } },
+        }),
+        commitDirectoryMutations: () => undefined,
+      },
+    );
+    directory.connectionChanged({
+      client: client as unknown as DaemonClient,
+      status: "online",
+      source: { clientGeneration: 1, connectionEpoch: 1 },
+    });
+    const store = useSessionStore.getState();
+    store.initializeSession(serverId, client as unknown as DaemonClient, 1);
+    store.updateSessionServerInfo(serverId, {
+      serverId,
+      hostname: null,
+      version: "test",
+      features: { workspaceMultiplicity: true, directorySync: true },
+    });
+
+    const refresh = directory.refreshAgents();
+    await expect.poll(() => client.fetchAgentsCalls).toBe(1);
+    releaseNetwork({
+      requestId: "agents",
+      entries: [],
+      pageInfo: { hasMore: false, nextCursor: null, prevCursor: null },
+      sync: { generation: "g", headSeq: 7, mode: "changes", removals: [] },
+    });
+    await refresh;
+
+    expect(client.lastAgentOptions).toMatchObject({
+      sync: { generation: "g", afterSeq: 7 },
+    });
+    expect(useSessionStore.getState().sessions[serverId]?.agents.has(cachedAgent.id)).toBe(true);
+    directory.dispose();
+  });
+
   it("does not use a cached checkpoint when the corresponding cache read loses its race", async () => {
     const serverId = "late-directory-cache";
     serverIds.add(serverId);