Gemini Bad Request with Github Copilot

Description

No matter which Gemini model I use with Github Copilot authentication I get a Bad Request: Bad Request error

It works for a colleague with the same Github Copilot license from our company.

I can prompt Gemini from the Copilot CLI

EDIT:
Found the issue. Gemini models fail with the Docker Gateway MCP with the Linear plugin enabled

Plugins

Tried both with and without "opencode-openai-codex-auth" installed

OpenCode version

1.1.19

Steps to reproduce

Authenticate with Github Copilot
Have Docker MCP gateway with Linear plugin enabled
Select any Gemini model
Write any prompt
Receive Bad Request: Bad Request error

Screenshot and/or share link

Operating System

macOS 26.1

Terminal

Ghostty and macOS Terminal

This issue might be a duplicate of existing issues. Please check:

Bug: 'Invalid request body' with github-copilot/gemini-3-pro-preview model #5161: Invalid request body with github-copilot/gemini-3-pro-preview - same Bad Request error pattern
Could not use model "Gemini 3 Pro Preview" of Github copilot provider: "invalid request body" #4816: Bad request with Gemini 3 Pro Preview through Github Copilot
github copilot: Gemini 3.0 invalid body request #4468: Gemini 3.0 invalid body request with Copilot (longstanding issue from v1.0.76)
Opencode Github Agent with GitHub Copilot provider Throw AI_APICallError: Bad Request #3287: Bad Request error with GitHub Copilot provider (broader pattern)
Copilot models respond with AI_APICallError: Bad Request after a quick chat #1282: Copilot models respond with Bad Request after use (affects Gemini and other models)

The root cause appears to be related to request body transformation when using Gemini models with Copilot authentication. Issues #5161 and #4816 are particularly similar to your case.

Feel free to ignore if none of these address your specific case.

I found configuration causing the problem. I updated the description.

In my case it was the Docker Gateway MCP with the Linear plugin enabled. It might be the Linear MCP by itself. It works fine with the other plugins I have in the Docker MCP toolkit. But removing the Linear plugin fixed the issue on my end.

I have the same issue with chrome-devtools-mcp@latest.

Although interestingly starting that MCP with --no-category-emulation lets it work with GitHub-hosted Gemini 3 models. Very odd.

@smerrill

@smerrill

Gemini models require nullable types to use OpenAPI 3.0 nullable keyword instead of JSON Schema union types

(from vscode copilot extension)

Had the same issue with chrome_devtools and this ended up being the reason.
--no-category-emulation disables emulate which is the only tool with nullable types

I'm having the same problem with Chrome DevTools，After configuring the same parameters, the problem is solved with --no-category-emulation。

ah yeah ig we need to sanitize the tools more aggressively for gemini

The strange thing is that this is only a problem for Copilot Gemini 3, not directly via the gemini-auth plugin.

Yup, can confirm. Running from a directory without MCP configs (no chrome-devtools-mcp especially) allowed Copilot Gemini to work

Yup, can confirm. Running from a directory without MCP configs (no chrome-devtools-mcp especially) allowed Copilot Gemini to work

Yup, I can confirm that the sentry mcp server is also causing this issue for me.

Same here, with the Linear MCP

It looks like there is an attempted fix here: #11968

I believe this should be fixed in next release

These seem to be also related to #14509 in recent conditions.
I have no Chrome DevTools MCP, but I am still getting a Bad Request too.

add '--no-category-emulation' for chrome-devtools mcp:

"chrome-devtools": {
            "type": "local",
            "command": [
                "npx",
                "-y",
                "chrome-devtools-mcp@latest",
                "--no-category-emulation" 
            ],
            "enabled": true
        },

instagit mcp also introduces the same issue

I have the same issue with zereight/mcp-gitlab

I got same issue with Notion official remote MCP server.

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "notion": {
      "type": "remote",
      "url": "https://mcp.notion.com/mcp",
      "enabled": true
    }
  }
}

Still an issue on Opencode 1.2.25. Chrome devtools mcp breaks both Gemini flash 3.0 (copilot) and GLM5 (nanogpt).

I'm not sure when this was fixed, but the issue no longer seems to occur in the current version 1.2.27. How about everyone else? I don't think Notion MCP was suddenly patched or anything...

I still have this issue with the Jetbrains built-in MCP server on Opencode 1.3.13

jetbrains_opencode_mcp_bad_request.webm

To me it was working really good last week but not it does not work anymore, just a Bad Request for any Gemini model on Copilot. All Gemini models are enabled in https://github.com/settings/copilot/features and I've "unlimited" budget for now (this an enterprise account).

Last week usage from opencode stats:

Logs:

$ opencode --version
1.16.2

INFO  2026-06-09T11:16:51 +0ms service=bus type=session.status publishing
INFO  2026-06-09T11:16:51 +1ms service=llm providerID=github-copilot modelID=gemini-3-flash-preview session.id=ses_153e68fa7ffet8Tfjdff8dTyMa small=false agent=build mode=primary stream
INFO  2026-06-09T11:16:51 +0ms service=provider status=started providerID=github-copilot getSDK
INFO  2026-06-09T11:16:51 +0ms service=provider status=completed duration=0 providerID=github-copilot getSDK
INFO  2026-06-09T11:16:51 +6ms service=default llm.runtime=ai-sdk llm.provider=github-copilot llm.model=gemini-3-flash-preview llm runtime selected
INFO  2026-06-09T11:16:52 +592ms service=bus type=session.updated publishing
ERROR 2026-06-09T11:16:52 +93ms service=llm providerID=github-copilot modelID=gemini-3-flash-preview session.id=ses_153e68fa7ffet8Tfjdff8dTyMa small=false agent=build mode=primary error={"error":{"name":"AI_APICallError","url":"https://api.githubcopilot.com/chat/completions","requestBodyValues":{"model":"gemini-3-flash-preview","max_tokens":32000,"temperature":1,"top_p":0.95,"messages":[...],"tool_choice":"auto","stream":true},"statusCode":400,"responseHeaders":{"cache-control":"no-cache","content-security-policy":"default-src 'none'; sandbox","content-type":"text/plain; charset=utf-8","date":"Tue, 09 Jun 2026 11:16:52 GMT","strict-transport-security":"max-age=31536000","transfer-encoding":"chunked","x-content-type-options":"nosniff","x-copilot-api-exp-assignment-context":"5133j383:1109202;c_a15ch289:1165001;","x-copilot-service-request-id":"dbb73113-bccc-4129-ab84-c746ae27e505","x-github-backend":"Kubernetes","x-github-request-id":"F0DE:1AC31E:426470B:46D8DA6:6A27F622","x-request-id":"00000-745affe7-5b90-4fc5-9375-a0d6a42c329c"},"responseBody":"Bad Request\n","isRetryable":false}} stream error
ERROR 2026-06-09T11:16:52 +6ms service=session.processor session.id=ses_153e68fa7ffet8Tfjdff8dTyMa messageID=msg_eac19734c0014A3U1O5hjV8CuC error=Bad Request stack=AI_APICallError: Bad Request
    at <anonymous> (/$bunfs/root/chunk-w4xmcxp8.js:6:14766)
    at async <anonymous> (/$bunfs/root/chunk-w4xmcxp8.js:6:12790)
    at processTicksAndRejections (native:7:39) process
INFO  2026-06-09T11:16:52 +0ms service=bus type=session.error publishing
INFO  2026-06-09T11:16:52 +0ms service=bus type=session.status publishing
INFO  2026-06-09T11:16:52 +0ms service=bus type=session.idle publishing
INFO  2026-06-09T11:16:52 +2ms service=bus type=message.updated publishing
INFO  2026-06-09T11:16:52 +1ms service=bus type=session.status publishing
INFO  2026-06-09T11:16:52 +0ms service=bus type=session.idle publishing
Error: Bad Request: Bad Request

UPDATE

Removing the Github MCP seems to solve the problem:

This is the github MCP I was using

        "github": {
          "type": "remote",
          "url": "https://api.githubcopilot.com/mcp/",
          "headers": {
            "Authorization": "Bearer <token>"
          }
        }

hmm, I am using 2 MCP, engram and public-browser. I disabled them and error still occurs.

ERROR 2026-06-09T14:58:04 +258ms service=llm providerID=github-copilot modelID=gemini-3.5-flash session.id=ses_15330b0b6ffevY1sDxQDY9tDZ3 small=false agent=plan mode=primary error={"error":{}} stream error
ERROR 2026-06-09T14:58:04 +2ms service=session.processor session.id=ses_15330b0b6ffevY1sDxQDY9tDZ3 messageID=msg_eace3fdbf002QXzLglc5GKWzb8 error=Copilot token exchange failed (404): {"message":"Not Found","documentation_url":"https://docs.github.com/rest","status":"404"} stack=Error: Copilot token exchange failed (404): {"message":"Not Found","documentation_url":"https://docs.github.com/rest","status":"404"}
    at <anonymous> (/Users/u132515/.cache/opencode/packages/opencode-copilot-enhanced@latest/node_modules/opencode-copilot-enhanced/dist/index.js:59:19)
    at processTicksAndRejections (native:7:39) process

I installed copilot enhanced plugin and now error is more visible rather than 400-Bad request

I just tried using Gemini models with Crush(https://github.com/charmbracelet/crush) and it's working there.

Can we say, something broken in opencode?

I am using 2 MCP: public-browser, engram

Gemini models started to working. I just tried Gemini 3.1. pro and it worked. I wanted to let you know. Since my last message i didn't change anything.

To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.

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Gemini Bad Request with Github Copilot #8417

Description

Plugins

OpenCode version

Steps to reproduce

Screenshot and/or share link

Operating System

Terminal

2 remaining items

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Gemini Bad Request with Github Copilot #8417

Description

Description

Plugins

OpenCode version

Steps to reproduce

Screenshot and/or share link

Operating System

Terminal

Activity

github-actions commented on Jan 14, 2026

ngt-sg commented on Jan 14, 2026

smerrill commented on Jan 29, 2026

smerrill commented on Jan 29, 2026

NateSmyth commented on Jan 29, 2026

fujunchao commented on Jan 31, 2026

rekram1-node commented on Jan 31, 2026

smerrill commented on Jan 31, 2026

dinhphieu commented on Feb 2, 2026

mattleong commented on Feb 2, 2026

alvinometric commented on Feb 3, 2026

rekram1-node commented on Feb 3, 2026

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Tetrahedrite commented on Mar 11, 2026

kvn1351 commented on Mar 13, 2026

Tetrahedrite commented on Mar 19, 2026

iamniels commented on Apr 1, 2026

ricardo-markiewicz-cs commented on Jun 9, 2026

UPDATE

Kjaer commented on Jun 9, 2026

Kjaer commented on Jun 11, 2026

Kjaer commented on Jun 16, 2026

github-actions commented on Aug 16, 2026

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