Keep an archived agent archived when a send to it fails (#6255)

* Keep an archived agent archived when a send to it fails

Sending a message to an archived agent unarchives it before loading the
session. When loading failed, for example because the agent's working
directory was removed, the agent stayed unarchived. The send now restores
the original archive timestamp when it fails, matching resume_agent.

Closes #6245

* Restore the archive only when the send cannot load the agent

Concurrent sends share one load, so a failed load leaves no session for
the restore to close. A failure after the load no longer re-archives an
agent another send may already be running.

---------

Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>

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

@@ -309,18 +309,30 @@ export async function sendPromptToAgent(
   const unarchive = params.unarchive ?? true;
 
   const record = await params.agentStorage.get(params.agentId);
+  let archivedAtToRestore: string | null = null;
   if (record?.archivedAt) {
     if (!unarchive) {
       return { disposition: "turn_started" };
     }
-    await unarchiveAgentState(params.agentStorage, params.agentManager, params.agentId);
+    if (await unarchiveAgentState(params.agentStorage, params.agentManager, params.agentId)) {
+      archivedAtToRestore = record.archivedAt;
+    }
   }
 
-  await ensureAgentLoaded(params.agentId, {
-    agentManager: params.agentManager,
-    agentStorage: params.agentStorage,
-    logger: params.logger,
-  });
+  try {
+    await ensureAgentLoaded(params.agentId, {
+      agentManager: params.agentManager,
+      agentStorage: params.agentStorage,
+      logger: params.logger,
+    });
+  } catch (error) {
+    // A send that could not load the agent leaves it where it was: still archived.
+    // Concurrent sends share this load, so none of them holds a live session.
+    if (archivedAtToRestore) {
+      await params.agentManager.archiveSnapshot(params.agentId, archivedAtToRestore);
+    }
+    throw error;
+  }
 
   if (params.sessionMode) {
     await params.agentManager.setAgentMode(params.agentId, params.sessionMode);

packages/server/src/server/daemon-client.e2e.test.ts

@@ -831,6 +831,29 @@ test("send_agent_message auto-unarchives archived agents", async () => {
   }
 }, 180000);
 
+test("send_agent_message leaves an archived agent archived when its directory is gone", async () => {
+  const cwd = tmpCwd();
+  try {
+    const created = await ctx.client.createAgent({
+      config: {
+        ...getFullAccessConfig("codex"),
+        cwd,
+      },
+    });
+    const archived = await ctx.client.archiveAgent(created.id);
+    rmSync(cwd, { recursive: true, force: true });
+
+    await expect(ctx.client.sendMessage(created.id, "hello")).rejects.toThrow(
+      "Working directory does not exist",
+    );
+
+    const afterSend = await ctx.client.fetchAgent({ agentId: created.id });
+    expect(afterSend?.agent.archivedAt).toBe(archived.archivedAt);
+  } finally {
+    rmSync(cwd, { recursive: true, force: true });
+  }
+}, 30000);
+
 test("refresh_agent auto-unarchives archived agents", async () => {
   const cwd = tmpCwd();
   try {