BUG: all requests made for the antigravity provider return error 500

[AykhanUV]

all requests made for the antigravity provider return error 500, antigravity itself works fine

[mirrobot-agent]

@AykhanUV Thank you for submitting this issue. I am now beginning my analysis and will report back shortly.

[AykhanUV]

here's the error log btw

{"timestamp": "2025-12-16T17:09:17.868042", "api_key_ending": "antigravity_oauth_6.json", "model": "antigravity/gemini-3-pro-preview", "attempt_number": 1, "error_type": "StreamedAPIError", "error_message": "Provider error received in stream", "raw_response": "{\n  \"error\": {\n    \"code\": 500,\n    \"message\": \"Internal error encountered.\",\n    \"status\": \"INTERNAL\"\n  }\n}\n", "request_headers": {"host": "127.0.0.1:8000", "connection": "keep-alive", "accept": "application/json", "x-stainless-retry-count": "0", "x-stainless-lang": "js", "x-stainless-package-version": "5.12.2", "x-stainless-os": "Windows", "x-stainless-arch": "x64", "x-stainless-runtime": "node", "x-stainless-runtime-version": "v22.21.1", "authorization": "Bearer a", "http-referer": "https://kilocode.ai", "x-title": "Kilo Code", "x-kilocode-version": "4.138.0", "user-agent": "Kilo-Code/4.138.0", "content-type": "application/json", "accept-language": "*", "sec-fetch-mode": "cors", "accept-encoding": "gzip, deflate", "content-length": "491907"}, "error_chain": [{"type": "StreamedAPIError", "message": "Provider error received in stream"}, {"type": "HTTPStatusError", "message": "Server error '500 Internal Server Error' for url 'https://daily-cloudcode-pa.sandbox.googleapis.com/v1internal:streamGenerateContent?alt=sse'\nFor more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/500"}]}

[mirrobot-agent]

Initial Analysis Report

Summary: The error 500 for the Antigravity provider is likely a server-side issue from Google's Antigravity API (cloudcode-pa.googleapis.com), not a proxy bug. The proxy already has fallback logic for 500 errors, but the underlying API may be experiencing issues.

Issue Validation: Needs More Info

Reproducibility Assessment: Needs More Info

Root Cause Analysis:

Based on code analysis of antigravity_provider.py:

1. HTTP 500 errors are server-side: Error 500 (Internal Server Error) indicates an issue on Google's Antigravity API servers, not the proxy itself.

2. Existing fallback mechanism: The provider already has URL fallback logic (antigravity_provider.py:3303-3333) that switches between base URLs when 500 errors occur:

   • Primary: https://daily-cloudcode-pa.sandbox.googleapis.com/v1internal
   • Fallback: https://cloudcode-pa.googleapis.com/v1internal (production)

3. Related issue Antigravity Forbidden Error 403 #37: Issue Antigravity Forbidden Error 403 #37 reports 403 Forbidden errors for the same provider, which suggests potential credential or permission issues that could also manifest as 500 errors.

4. Potential causes of 500 errors:

   • Malformed request payload (message transformation issues)
   • Thinking/signature sanitization errors in multi-turn conversations
   • API instability on Google's side (sandbox vs production endpoints)
   • Quota-related issues being returned as 500 instead of 429

5. Relevant code paths:

   • Request transformation: _transform_messages() (line 1788)
   • Antigravity format conversion: _transform_to_antigravity_format() (line 2584)
   • Thinking sanitization for Claude: _sanitize_thinking_for_claude() (line 1231)
   • Error handling: acompletion() (line 3088)

Suggested Labels: bug, needs-reproduction, provider-antigravity

Proposed Next Steps:

1. Enable detailed logging: Set environment variable ANTIGRAVITY_ENABLE_LOGGING=true to capture full request/response payloads in logs/antigravity_logs/.

2. Check logs: Review the failures.log file in the logs directory for the full error response body from the API.

3. Test both endpoints: Manually check if both sandbox (daily-cloudcode-pa.sandbox.googleapis.com) and production (cloudcode-pa.googleapis.com) endpoints are returning 500 errors.

4. Verify model selection: Confirm which model(s) are causing the 500 error (claude-sonnet-4-5, claude-opus-4-5, or gemini-3-pro-preview).

Missing Information (if any):

To effectively diagnose this issue, please provide:

1. Full error message: Complete error output from the proxy logs
2. Request type: Which model was being used? (e.g., antigravity/claude-sonnet-4-5)
3. Request context: Was this a simple chat completion, or did it involve tool calls or multi-turn conversation?
4. Reproducibility: Does this happen on every request, or intermittently?
5. Environment details:
   • Operating system
   • Python version
   • Any custom environment variables for Antigravity
6. Credential tier: Is this a free-tier or paid-tier Google account (visible in credential metadata)?

This analysis was generated by an AI assistant.

[AykhanUV]

I've already provided logs
Applies for all models
kilo code request, so probably tool calling
it happens on every request
Windows 11
Free tier, fresh account

Again, antigravity itself works normally with the same oauth & account

[Mirrowel]

all requests made for the antigravity provider return error 500, antigravity itself works fine

what version are you on? You should have full error in the failures.log for the credential.

Also need to see the log itself as well, cause that is not normal and i don't have any of that. proxy.log, proxy_debug.log

[AykhanUV]

I've tried the latest stable and dev builds.

here are the complete logs

2025-12-16 21:09:09,330 - root - INFO - 21:09 - 127.0.0.1:54845 - provider: antigravity, model: gemini-3-pro-preview - N/A
2025-12-16 21:09:09,331 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 0/7(7)
2025-12-16 21:09:09,332 - rotator_library - INFO - Acquired key antigravity_oauth_3.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 10)
2025-12-16 21:09:09,332 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_3.json (Attempt 1/2)
2025-12-16 21:09:09,332 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_3.json. Processing response.
2025-12-16 21:09:11,226 - rotator_library - WARNING - Caught a critical API error mid-stream: HTTPStatusError. Signaling for credential rotation.
2025-12-16 21:09:11,226 - rotator_library - INFO - Released credential antigravity_oauth_3.json from model antigravity/gemini-3-pro-preview (remaining concurrent: 0)
2025-12-16 21:09:11,226 - rotator_library - INFO - STREAM FINISHED and lock released for credential antigravity_oauth_3.json.
2025-12-16 21:09:11,227 - rotator_library - ERROR - API call failed for model antigravity/gemini-3-pro-preview with key antigravity_oauth_3.json. Error: StreamedAPIError. See failures.log for details.
2025-12-16 21:09:11,227 - rotator_library - INFO - Provider-level error (server_error) for key antigravity_oauth_3.json with model antigravity/gemini-3-pro-preview. NOT incrementing failures. Cooldown: 30s
2025-12-16 21:09:11,229 - rotator_library - WARNING - Cred antigravity_oauth_3.json server_error (HTTP 500). Rotating.
2025-12-16 21:09:11,229 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 1/6(7)
2025-12-16 21:09:11,230 - rotator_library - INFO - Acquired key antigravity_oauth_4.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 0)
2025-12-16 21:09:11,230 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_4.json (Attempt 1/2)
2025-12-16 21:09:11,230 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_4.json. Processing response.
2025-12-16 21:09:12,683 - rotator_library - WARNING - Caught a critical API error mid-stream: HTTPStatusError. Signaling for credential rotation.
2025-12-16 21:09:12,683 - rotator_library - INFO - Released credential antigravity_oauth_4.json from model antigravity/gemini-3-pro-preview (remaining concurrent: 0)
2025-12-16 21:09:12,683 - rotator_library - INFO - STREAM FINISHED and lock released for credential antigravity_oauth_4.json.
2025-12-16 21:09:12,684 - rotator_library - ERROR - API call failed for model antigravity/gemini-3-pro-preview with key antigravity_oauth_4.json. Error: StreamedAPIError. See failures.log for details.
2025-12-16 21:09:12,684 - rotator_library - INFO - Provider-level error (server_error) for key antigravity_oauth_4.json with model antigravity/gemini-3-pro-preview. NOT incrementing failures. Cooldown: 30s
2025-12-16 21:09:12,686 - rotator_library - WARNING - Cred antigravity_oauth_4.json server_error (HTTP 500). Rotating.
2025-12-16 21:09:12,686 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 2/5(7)
2025-12-16 21:09:12,687 - rotator_library - INFO - Acquired key antigravity_oauth_5.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 0)
2025-12-16 21:09:12,687 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_5.json (Attempt 1/2)
2025-12-16 21:09:12,687 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_5.json. Processing response.
2025-12-16 21:09:13,967 - rotator_library - WARNING - Caught a critical API error mid-stream: HTTPStatusError. Signaling for credential rotation.
2025-12-16 21:09:13,967 - rotator_library - INFO - Released credential antigravity_oauth_5.json from model antigravity/gemini-3-pro-preview (remaining concurrent: 0)
2025-12-16 21:09:13,967 - rotator_library - INFO - STREAM FINISHED and lock released for credential antigravity_oauth_5.json.
2025-12-16 21:09:13,968 - rotator_library - ERROR - API call failed for model antigravity/gemini-3-pro-preview with key antigravity_oauth_5.json. Error: StreamedAPIError. See failures.log for details.
2025-12-16 21:09:13,968 - rotator_library - INFO - Provider-level error (server_error) for key antigravity_oauth_5.json with model antigravity/gemini-3-pro-preview. NOT incrementing failures. Cooldown: 30s
2025-12-16 21:09:13,969 - rotator_library - WARNING - Cred antigravity_oauth_5.json server_error (HTTP 500). Rotating.
2025-12-16 21:09:13,969 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 3/4(7)
2025-12-16 21:09:13,970 - rotator_library - INFO - Acquired key antigravity_oauth_1.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 0)
2025-12-16 21:09:13,970 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_1.json (Attempt 1/2)
2025-12-16 21:09:13,971 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_1.json. Processing response.
2025-12-16 21:09:15,151 - rotator_library - WARNING - Caught a critical API error mid-stream: HTTPStatusError. Signaling for credential rotation.
2025-12-16 21:09:15,151 - rotator_library - INFO - Released credential antigravity_oauth_1.json from model antigravity/gemini-3-pro-preview (remaining concurrent: 0)
2025-12-16 21:09:15,151 - rotator_library - INFO - STREAM FINISHED and lock released for credential antigravity_oauth_1.json.
2025-12-16 21:09:15,151 - rotator_library - ERROR - API call failed for model antigravity/gemini-3-pro-preview with key antigravity_oauth_1.json. Error: StreamedAPIError. See failures.log for details.
2025-12-16 21:09:15,151 - rotator_library - INFO - Provider-level error (server_error) for key antigravity_oauth_1.json with model antigravity/gemini-3-pro-preview. NOT incrementing failures. Cooldown: 30s
2025-12-16 21:09:15,153 - rotator_library - WARNING - Cred antigravity_oauth_1.json server_error (HTTP 500). Rotating.
2025-12-16 21:09:15,153 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 4/3(7)
2025-12-16 21:09:15,154 - rotator_library - INFO - Acquired key antigravity_oauth_2.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 0)
2025-12-16 21:09:15,154 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_2.json (Attempt 1/2)
2025-12-16 21:09:15,154 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_2.json. Processing response.
2025-12-16 21:09:16,557 - rotator_library - WARNING - Caught a critical API error mid-stream: HTTPStatusError. Signaling for credential rotation.
2025-12-16 21:09:16,557 - rotator_library - INFO - Released credential antigravity_oauth_2.json from model antigravity/gemini-3-pro-preview (remaining concurrent: 0)
2025-12-16 21:09:16,557 - rotator_library - INFO - STREAM FINISHED and lock released for credential antigravity_oauth_2.json.
2025-12-16 21:09:16,558 - rotator_library - ERROR - API call failed for model antigravity/gemini-3-pro-preview with key antigravity_oauth_2.json. Error: StreamedAPIError. See failures.log for details.
2025-12-16 21:09:16,558 - rotator_library - INFO - Provider-level error (server_error) for key antigravity_oauth_2.json with model antigravity/gemini-3-pro-preview. NOT incrementing failures. Cooldown: 30s
2025-12-16 21:09:16,560 - rotator_library - WARNING - Cred antigravity_oauth_2.json server_error (HTTP 500). Rotating.
2025-12-16 21:09:16,560 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 5/2(7)
2025-12-16 21:09:16,560 - rotator_library - INFO - Acquired key antigravity_oauth_6.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 0)
2025-12-16 21:09:16,561 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_6.json (Attempt 1/2)
2025-12-16 21:09:16,561 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_6.json. Processing response.
2025-12-16 21:09:17,868 - rotator_library - WARNING - Caught a critical API error mid-stream: HTTPStatusError. Signaling for credential rotation.
2025-12-16 21:09:17,868 - rotator_library - INFO - Released credential antigravity_oauth_6.json from model antigravity/gemini-3-pro-preview (remaining concurrent: 0)
2025-12-16 21:09:17,868 - rotator_library - INFO - STREAM FINISHED and lock released for credential antigravity_oauth_6.json.
2025-12-16 21:09:17,869 - rotator_library - ERROR - API call failed for model antigravity/gemini-3-pro-preview with key antigravity_oauth_6.json. Error: StreamedAPIError. See failures.log for details.
2025-12-16 21:09:17,869 - rotator_library - INFO - Provider-level error (server_error) for key antigravity_oauth_6.json with model antigravity/gemini-3-pro-preview. NOT incrementing failures. Cooldown: 30s
2025-12-16 21:09:17,870 - rotator_library - WARNING - Cred antigravity_oauth_6.json server_error (HTTP 500). Rotating.
2025-12-16 21:09:17,871 - rotator_library - INFO - Acquiring credential for model antigravity/gemini-3-pro-preview. Tried credentials: 6/1(7)
2025-12-16 21:09:17,871 - rotator_library - INFO - Acquired key antigravity_oauth_7.json for model antigravity/gemini-3-pro-preview (tier: free-tier, priority: 3, selection: sequential, usage: 0)
2025-12-16 21:09:17,871 - rotator_library - INFO - Attempting stream with credential antigravity_oauth_7.json (Attempt 1/2)
2025-12-16 21:09:17,872 - rotator_library - INFO - Stream connection established for credential antigravity_oauth_7.json. Processing response.

[AykhanUV]

proxy_debug.log

2025-12-16 21:08:10,440 - rotator_library - DEBUG - Antigravity quota refresh: updated 42 model baselines
2025-12-16 21:08:10,440 - rotator_library - DEBUG - antigravity quota_baseline_refresh: initial run complete
2025-12-16 21:08:10,440 - rotator_library - DEBUG - ProviderCache[gemini3_signatures]: Started background tasks
2025-12-16 21:08:10,441 - rotator_library - DEBUG - ProviderCache[claude_thinking]: Loaded 19 entries (0 expired)
2025-12-16 21:08:10,441 - rotator_library - DEBUG - ProviderCache[claude_thinking]: Started background tasks
2025-12-16 21:09:09,330 - rotator_library - DEBUG - Handling reasoning parameters: model=antigravity/gemini-3-pro-preview, reasoning_effort=high, custom_reasoning_budget=False
2025-12-16 21:09:09,331 - rotator_library - DEBUG - Credential priorities for antigravity: P3=7
2025-12-16 21:09:09,332 - rotator_library - DEBUG - Sequential ordering: antigravity_oauth_3.json(p=3, u=10) → antigravity_oauth_4.json(p=3, u=0) → antigravity_oauth_5.json(p=3, u=0)
2025-12-16 21:09:09,332 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:09,332 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_3.json
2025-12-16 21:09:09,332 - rotator_library - DEBUG - Using cached project ID: seismic-bazaar-dc2qh
2025-12-16 21:09:11,230 - rotator_library - DEBUG - Sequential ordering: antigravity_oauth_4.json(p=3, u=0) → antigravity_oauth_5.json(p=3, u=0) → antigravity_oauth_1.json(p=3, u=0)
2025-12-16 21:09:11,230 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:11,230 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_4.json
2025-12-16 21:09:11,230 - rotator_library - DEBUG - Using cached project ID: fluted-index-cdpsm
2025-12-16 21:09:12,686 - rotator_library - DEBUG - Sequential ordering: antigravity_oauth_5.json(p=3, u=0) → antigravity_oauth_1.json(p=3, u=0) → antigravity_oauth_2.json(p=3, u=0)
2025-12-16 21:09:12,687 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:12,687 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_5.json
2025-12-16 21:09:12,687 - rotator_library - DEBUG - Using cached project ID: curious-epoch-qwppl
2025-12-16 21:09:13,970 - rotator_library - DEBUG - Sequential ordering: antigravity_oauth_1.json(p=3, u=0) → antigravity_oauth_2.json(p=3, u=0) → antigravity_oauth_6.json(p=3, u=0)
2025-12-16 21:09:13,970 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:13,970 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_1.json
2025-12-16 21:09:13,970 - rotator_library - DEBUG - Using cached project ID: fluid-cell-vw9k9
2025-12-16 21:09:15,154 - rotator_library - DEBUG - Sequential ordering: antigravity_oauth_2.json(p=3, u=0) → antigravity_oauth_6.json(p=3, u=0) → antigravity_oauth_7.json(p=3, u=0)
2025-12-16 21:09:15,154 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:15,154 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_2.json
2025-12-16 21:09:15,154 - rotator_library - DEBUG - Using cached project ID: earnest-smoke-ggvlf
2025-12-16 21:09:16,560 - rotator_library - DEBUG - Sequential ordering: antigravity_oauth_6.json(p=3, u=0) → antigravity_oauth_7.json(p=3, u=0)
2025-12-16 21:09:16,561 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:16,561 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_6.json
2025-12-16 21:09:16,561 - rotator_library - DEBUG - Using cached project ID: turnkey-framing-3bmtp
2025-12-16 21:09:17,871 - rotator_library - DEBUG - Provider 'antigravity' has custom logic. Delegating call.
2025-12-16 21:09:17,871 - rotator_library - DEBUG - Starting Antigravity project discovery for credential: C:\Users\Aykhan\Desktop\LLM\oauth_creds\antigravity_oauth_7.json
2025-12-16 21:09:17,871 - rotator_library - DEBUG - Using cached project ID: level-choir-vf8b1

[Mirrowel]

Server error. Did you try claude models? does it happen there?
Not much i can do without a full error captured. Never got a server error 500.

[AykhanUV]

It works now, it might have been an issue on their servers. Thanks

[AykhanUV]

I found out the problem, it happens on all models, after passing 100k context window. I don't know if antigravity itself limits it there and resets each time, or this code is sending some wrong parameters which cause error 500
@Mirrowel

[Phosphate5429]

I found out the problem, it happens on all models, after passing 100k context window. I don't know if antigravity itself limits it there and resets each time, or this code is sending some wrong parameters which cause error 500 @Mirrowel

same issue, often "OpenAI completion error: 500 status code (no body)" coming after few requests answers from opus.

[Mirrowel]

I found out the problem, it happens on all models, after passing 100k context window. I don't know if antigravity itself limits it there and resets each time, or this code is sending some wrong parameters which cause error 500

doesn't happen to me. Opus/sonnet have 200k. Gemini 3 has 1M.

Try using latest dev, both of you.
No body error is literally that - no body. It should be fixed with retries(look in the proxy console).
If retries don't help - i can't do anything else for you. This is antigravity sending literally nothing and ending.

Btw, they seem to rate limit paid users for some reason, as this happened to me constantly on a paid account - but not free account.