Bug: Agent final reply rendered into the wrong chat thread

Support Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

When multiple Agent/Chat sessions are open (or background agent tasks finish), the final text reply from one conversation appears inside a different conversation’s Agent window.

The originating chat may show only the tool-activity timeline (Await / Explored / Run command) with no visible text reply, while another unrelated thread receives that reply content.

Example: chat titled “Character definition support” showed a completion message about finishing 7 background email-outreach tasks and file diffs for send_outreach_100_20260821.py — clearly belonging to a different “邮件营销” workflow.

Also coincided with the banner: “Usage limit reached. You’ve reached your limit. Responses may be slower.”

Steps to Reproduce

  1. Open multiple chats in the Agents sidebar (e.g. Chat A for email outreach work, Chat B titled “Character definition support”).
  2. In Chat A, run a longer Agent task that uses tools / background terminals and may edit files.
  3. Optionally hit the usage-limit banner (“Usage limit reached… Responses may be slower”).
  4. While Chat A is finishing (or shortly after), keep Chat B focused/selected.
  5. Observe where the final natural-language completion reply appears.

Expected Behavior

The final assistant reply (and related completion UI) should appear only in the chat that started the Agent run (Chat A). Other chats must not receive that reply.

Actual: Chat A often shows only tool activity (Await / Explored / Run command) with little or no text bubble, while Chat B incorrectly shows Chat A’s completion text (e.g. email outreach results / file change summaries).

Operating System

Windows 10/11

Version Information

Cursor 3.17.8 (User install)
Also present on disk: Cursor app package 3.16.29
OS: Windows 10 Pro 22H2 (Build 19045)
UI: Agents sidebar multi-chat + Background terminals

Additional Information

Suspected routing bug: Agent completion/events attach to the currently focused chat instead of the originating conversation id, especially with concurrent agents / usage-limit state.

Related symptoms in the same session:

  • Origin chat shows tool log only, no final text reply
  • Wrong chat receives the completion narrative and file-change widget

Happy to provide more logs/screenshots if needed.

Does this stop you from using Cursor

No - Cursor works, but with this issue

5

Hey, thanks for the detailed report. It’s really well written, and it helps a lot.

To narrow down the cause, I need a couple quick details:

  1. Were the two chats tied to different projects or folders, or opened in different Cursor windows, or were they in the same workspace?
  2. Please send the Request ID from the chat that didn’t get the final text reply. Open that chat > ⋯ menu in the top-right corner > Copy Request ID.
  3. If it happens again on the latest version after a restart, let me know too. That’s a useful detail.

Once I have those answers, it’ll be clearer what’s going on with routing completed background tasks between chats. Screenshots or logs are welcome too if you have them.