Q7: an agent runs one session at a time

Claims skip agents that already have a running run, manual runs refuse a
busy agent, a run whose task was reassigned fails before executing, and
tasks with a run in progress cannot be deleted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/unit/claim-priority.test.ts

@@ -98,3 +98,41 @@ describe("queue claim priority", () => {
     h.connection.close();
   });
 });
+
+describe("one session per agent", () => {
+  test("a queued run for an agent that is already running waits; others proceed", () => {
+    const h = harness();
+    const spaceWithCeo = h.chat.ensureDirectSpace(h.orgId, { type: "employee", id: h.employeeId }, { type: "agent", id: h.ceoId });
+    const spaceWithDana = h.chat.ensureDirectSpace(h.orgId, { type: "employee", id: h.employeeId }, { type: "agent", id: h.danaId });
+    const say = (spaceId: string, bodyMd: string) => h.chat.sendMessage({
+      orgId: h.orgId, spaceId, threadId: null, senderType: "employee", senderId: h.employeeId, bodyMd, attachmentFileIds: [],
+    });
+    say(spaceWithCeo, "First question?");
+    say(spaceWithCeo, "Second, separate question?");
+    say(spaceWithDana, "Dana, a question?");
+
+    const first = claimNextQueuedRun(h.connection)!;
+    expect(h.connection.db.prepare("select agent_id from task_runs where id = ?").get(first.id)).toEqual({ agent_id: h.ceoId });
+    const second = claimNextQueuedRun(h.connection)!;
+    expect(h.connection.db.prepare("select agent_id from task_runs where id = ?").get(second.id)).toEqual({ agent_id: h.danaId });
+    expect(claimNextQueuedRun(h.connection)).toBeNull();
+
+    h.connection.db.prepare("update task_runs set state = 'completed' where id = ?").run(first.id);
+    const third = claimNextQueuedRun(h.connection)!;
+    expect(h.connection.db.prepare("select agent_id from task_runs where id = ?").get(third.id)).toEqual({ agent_id: h.ceoId });
+    h.connection.close();
+  });
+
+  test("a running run whose agent was deleted blocks nobody", () => {
+    const h = harness();
+    const spaceWithDana = h.chat.ensureDirectSpace(h.orgId, { type: "employee", id: h.employeeId }, { type: "agent", id: h.danaId });
+    h.chat.sendMessage({ orgId: h.orgId, spaceId: spaceWithDana, threadId: null, senderType: "employee", senderId: h.employeeId, bodyMd: "Hi?", attachmentFileIds: [] });
+    h.connection.db.prepare(`
+      insert into task_runs(id, org_id, task_id, agent_id, provider_id, execution_context_id, service_identity_id, workspace_mount_json, secret_scope_json, trigger, state, created_at)
+      select 'run_orphan', org_id, task_id, null, provider_id, 'ctx_orphan', service_identity_id, workspace_mount_json, '{}', 'manual', 'running', created_at
+      from task_runs where agent_id = ?
+    `).run(h.danaId);
+    expect(h.connection.db.prepare("select agent_id from task_runs where id = ?").get(claimNextQueuedRun(h.connection)!.id)).toEqual({ agent_id: h.danaId });
+    h.connection.close();
+  });
+});

tests/unit/task-queue-worker.test.ts

@@ -40,14 +40,17 @@ describe("task queue worker claim", () => {
     const second = seedQueuedRun(connection, orgId, taskId, agentId, providerId);
 
     const claimedA = claimNextQueuedRun(connection);
+    // One session per agent: the second run waits while the first is running.
+    expect(claimNextQueuedRun(connection)).toBeNull();
+    connection.db.prepare("update task_runs set state = 'completed' where id = ?").run(claimedA!.id);
     const claimedB = claimNextQueuedRun(connection);
     const claimedC = claimNextQueuedRun(connection);
 
     expect([claimedA?.id, claimedB?.id].sort()).toEqual([first, second].sort());
     expect(claimedC).toBeNull();
 
-    const states = (connection.db.prepare("select state from task_runs where org_id = ? order by created_at").all(orgId) as Array<{ state: string }>).map((r) => r.state);
-    expect(states).toEqual(["running", "running"]);
+    const states = (connection.db.prepare("select state from task_runs where org_id = ? order by created_at").all(orgId) as Array<{ state: string }>).map((r) => r.state).sort();
+    expect(states).toEqual(["completed", "running"]);
     connection.close();
   });