Agent sends duplicate message #20699
Description
Description
When a user sends a simple message like "hello!", the agent generates two assistant responses instead of one:
Message 1 (hidden from user, but visible to agent): Contains the greeting text
Message 2 (shown to user): Has empty visible text, but its reasoning part says "I've already sent my response greeting them and asking what they need help with"
Both messages have the same parentID (replying to the same user message).
The user can only see Message 2, which makes the agent appear confused — its visible response is empty, and the reasoning references content from a message the user never saw.
In more complex queries (e.g., "Write a sorting algorithm"), the actual code or explanation in Message 1 is completely dropped. The user only sees a reasoning block saying:
"The user asked a direct question and I answered it clearly. The task is complete."
This results in a total failure of the agent's primary function, as the user receives no content despite the model believing it has fulfilled the request.
Expected Behavior
The reasoning and visible text should be consistent and directly address the user's prompt.
Actual Behavior
Message 1’s response is discarded or hidden, and Message 2 is generated as a "phantom" retry that lacks substance but inherits the "thought" process from the first attempt.
Plugins
None
OpenCode version
v1.3.12
Steps to reproduce
OpenCode is deployed on a Linux system. Accessing OpenCode via web on Windows leads to the aforementioned issues, but there are no such problems when using macOS.
Additionally, there is an assistant message located above the user's message and it is invisible—an extremely peculiar issue.
- User sends "hello!" or any simple greeting
- Observe: Two assistant messages are generated with the same parentID
- First message (hidden from UI): Contains visible greeting text
- Second message (shown to UI): Empty visible text, but reasoning references the first message's content
Screenshot and/or share link
Operating System
windows 11
Terminal
No response
Activity
github-actions commentedon Apr 2, 2026
This issue might be a duplicate of existing issues. Please check:
Please review these issues to see if they describe the same root cause.
sylac commentedon May 12, 2026
I can reproduce the “two responses for one prompt / Stop only cancels one” behavior on
opencode v1.14.48.Symptom
Strong log evidence
In the same session, I see two completed
POST /session/<session-id>/messageresponses with different span IDs and different durations:Why this looks wrong
That is consistent with two independent prompt executions reaching completion for the same user action.
Important caveat
These lines alone do not prove whether this was:
But together with the UI symptom, they are strong evidence that two pipelines were active and Stop only cancelled one of them.
Likely areas to inspect
If useful, I can also provide:
alterdaemon commentedon May 22, 2026
same problem, and this must be two separate calls because each duplicated answer differs slightly from each other. e. g. standard review agent.
OpenCode Desktop (via web server)
v1.15.6
Snowy117 commentedon Jun 1, 2026
same problem, only found in web/desktop. tui won't reproduce
v1.15.12
naomi-lgbt commentedon Jul 20, 2026
i am experiencing the same issue for the web ui i run for my personal affairs
i was able to reproduce in v1.17.13, v1.17.20, and v1.18.2
copilotenstar commentedon Jul 21, 2026
Same here getting duplicate replies and sometimes even 3 replies to one msg.
github-actions commentedon Sep 20, 2026
To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.