[BUG] error: "Function call is missing a thought_signature in functionCall parts"

[bowmanjd]

Bug Description
Upon making the first request in a session, I see that the request begins, but then it terminates early with a 400 error.

Steps to Reproduce

1. Use an antigravity model in OpenCode
2. Watch it begin
3. Then observe signature error

Expected Behavior
Succeed like it did yesterday

Actual Behavior
An error:

Function call is missing a thought_signature in functionCall parts. This is required for tools to work correctly, and missing thought_signature may lead to degraded model performance. Additional data, function call `default_api:context_info` , position 4. Please refer to https://ai.google.dev/gemini-api/docs/thought-signatures for more details.
...
[opencode-antigravity-auth debug]
- request=https://generativelanguage.googleapis.com/v1beta/models/antigravity-gemini-3-pro:streamGenerateContent?alt=sse
- selected idx=0 email=bowmanjd@gmail.com family=gemini accounts=1 strategy=sticky
- headerStyle=antigravity explicit=true
- endpoint=https://daily-cloudcode-pa.sandbox.googleapis.com
- resolved=https://daily-cloudcode-pa.sandbox.googleapis.com/v1internal:streamGenerateContent?alt=sse
- status=400 Bad Request

Environment

• opencode version: 1.1.12
• Plugin version: @beta
• Operating System: Linux
• Node.js version: v24.12.0

Logs

antigravity-debug-2026-01-14T12-30-25-158Z.log

Compliance Checklist
Please confirm:

• I'm using this plugin for personal development only
• I have an active Google Cloud project with Antigravity enabled
• This issue is not related to attempting commercial use or TOS violations
• I've reviewed the README troubleshooting section

[LuYongping]

same issue

[hkay-dev]

I run into this a lot. Also, @bowmanjd because Opencode is Opencode and moves super fast, your version is already several revisions behind; we are at 1.1.20 as of this writing, and I am sure by the time you read this, we will be further than that!

[bowmanjd]

To clarify @AuroraFlux -- the plugin version is independent of the OpenCode version, correct? I of course don't mind being at the bleeding edge, just curious.

[hkay-dev]

To clarify @auroraflux -- the plugin version is independent of the OpenCode version, correct? I of course don't mind being at the bleeding edge, just curious.

Yes! My apologies. They are independent (that is, unless the latest plugin takes into account fixes that were made in moer recent versions of OpenCode).

I did not mean to imply that your issue would be solved by updating!

[Lok17]

same issue

[bowmanjd]

Interesting... I just disabled the DCP plugin (@tarquinen/opencode-dcp@latest) and now everything is working fine again. If I re-enable it, it breaks again. Without the plugin, tool calls appear to be working fine. The only thing I can think that has changed is that I believe the DCP plugin no longer generates "user" role messages but instead uses "assistant" messages.

[DanRioDev]

This is a plague!

[maherlaaroussi]

Interesting... I just disabled the DCP plugin (@tarquinen/opencode-dcp@latest) and now everything is working fine again. If I re-enable it, it breaks again. Without the plugin, tool calls appear to be working fine. The only thing I can think that has changed is that I believe the DCP plugin no longer generates "user" role messages but instead uses "assistant" messages.

Thank you, I can confirm that disabling dcp plugin fix the issue.

[hkay-dev]

It appears there is ongoing discussion happening in the Discord for OpenCode. Here's a direct link: https://discord.com/channels/1391832426048651334/1448743098699087973.

[Tarquinen]

This was fixed in DCP Opencode-DCP/opencode-dynamic-context-pruning#265 @bowmanjd @DanRioDev @maherlaaroussi , however I think it's the OAuth plugins responsibility to validate all functions. Opencode plugins should be able to inject function calls without needing to add thought signatures for specific providers. For example, you can see how it's done here: https://github.com/Mirrowel/LLM-API-Key-Proxy/blob/088180f2e46ac068fd598eeab39865284719a55e/src/rotator_library/providers/antigravity_provider.py#L2566

edit: on second thought I don't think it's the auth plugins responsibility as gemini api requires the same thought signatures, anyway this is fixed in DCP now