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After updating to 2.1.2, DeepSeek writes “[Assistant tool call]” as text instead of executing tools #58027
Description
Description
This behavior started after updating OpenCode from 2.0.32 to 2.1.2. Before the update, tool calls worked normally.
In an existing conversation, the assistant now writes messages like:
“Now executing properly: [Assistant tool call]: ”
These appear as ordinary assistant text instead of actual tool calls. Asking it to execute properly can produce the same response again, without continuing the task.
Observations:
- Some actual tool calls still succeed, so the failure is intermittent.
- The server log also reported: “provider rejected the request as too long; compacting”.
- I cannot confirm whether compaction is involved, but the visible problem began after the update.
Downgrade attempt:
I tried downgrading to 2.0.32. Opening the same conversation then failed with:
“UnknownError: Unexpected server error. Check server logs for details.”
The server logs repeatedly showed “failed to decode session message” for the same message. This prevented me from continuing that conversation on the older version.
Expected:
Tool calls should execute normally, as they did before the update.
Actual:
The assistant sometimes imitates tool calls in plain text and stops. Attempting to return to the previous version also leaves the affected conversation inaccessible.
Possibly related:
#43247
#35689
Please let me know which sanitized logs or diagnostics would help investigate this.
Plugins
MCP
OpenCode version
2.1.2
Steps to reproduce
- Update OpenCode Desktop from 2.0.32 to 2.1.2.
- Open an existing long conversation using DeepSeek
deepseek-v4-prowith reasoning variantmax. - Ask the assistant to perform a task requiring tool calls.
- Continue the conversation through multiple tool calls.
- Observe that the assistant sometimes writes
[Assistant tool call]: <tool name and arguments>as ordinary text instead of executing a tool. - Ask it to execute the tool properly. It may repeat the same plain-text format and stop again.
This is intermittent; I do not yet have a minimal, reliably reproducible example. The affected session also triggered automatic compaction, but I have not confirmed whether that is required to reproduce the issue.
Screenshot
No response
Operating System
macos
Terminal
Desktop
Activity
opencode-agent commentedon Oct 22, 2026
Thanks for the detailed report, @awaxy! I think this is a duplicate of #50814.
The
[Assistant tool call]: <name>(<args>)text is the format OpenCode uses when it rewrites older history during compaction. After a compaction the model sees earlier tool calls in that text form and sometimes copies it instead of making a real tool call, so nothing runs. Your log lineprovider rejected the request as too long; compactingfits this. #50814 reports the same thing after auto-compaction on 2.0.x with several other models and providers, so it probably isn't specific to DeepSeek or to 2.1.2. It may just have shown up for you now because this session got compacted.Possible duplicates and related issues, ordered from most to least likely:
[Assistant tool call]: ...as literal text and the tools never run (same symptom, same string)The downgrade error looks like a separate issue: 2.1 changed how some session data is stored (#57260), so 2.0.32 can't read messages written by 2.1.x. That's why the session fails to decode there. It's best to stay on 2.1.x for that conversation.
If you can, please add your details to #50814 (DeepSeek
deepseek-v4-prowith themaxvariant, Desktop on macOS, 2.1.2) so it's all in one place. The bot will close this issue as a duplicate in 1 day unless you reply explaining how your problem is different.opencode-agent commentedon Oct 23, 2026
Closing this as a duplicate of #50814, since nobody has replied to say how it differs. Both describe the same problem: after automatic compaction, the model writes
[Assistant tool call]: <name>(<args>)as plain text, so the tool never runs.Please add your details to #50814 so they're all in one place:
deepseek-v4-prowith themaxvariant, on OpenCode Desktop 2.1.2 on macOSprovider rejected the request as too long; compactinglog lineThe downgrade error (
failed to decode session messageon 2.0.32) is a separate matter: 2.0.32 can't read sessions written by 2.1.x.If this turns out to be a different problem, reply here and we can reopen it. Thanks for the report, @awaxy!