dsh-llm-antigravity

A native LLM adapter plugin for DeepSeek Harness (dsh) that connects in-process to Google Cloud Code Assist (Antigravity).

Allows your dsh Web GUI and agents to directly use Gemini and Claude models (including Gemini 3.8 Flash, Gemini 3.7 Flash, Claude Sonnet 4.6, Claude Opus 4.6, etc.) using your Google AI Pro plan entitlements via OAuth, with zero external proxy sidecars required.

Features

• Native in-process adapter: Implements @deepseek-ai/dsh-llm's LlmAdapter contract directly. No standalone HTTP proxy daemon required.
• Direct Cloud Code Assist wire protocol: Speaks the internal Google RPC protocol (v1internal:streamGenerateContent) with proper request envelopes, session trajectory IDs, thinking configurations, and protobuf struct encapsulation.
• Thought signature replay: Preserves and restores Gemini 3.x thoughtSignature across tool-calling loops, preventing upstream 400 validation errors. Gracefully falls back to observation blocks when migrating across providers.
• Auto token refresh: Reuses existing Google OAuth credentials from your system and refreshes expired access tokens automatically before request dispatch.
• 3-Endpoint fallback: Automatic routing across Google endpoints (daily-cloudcode-pa.googleapis.com, daily-cloudcode-pa.sandbox.googleapis.com, and cloudcode-pa.googleapis.com).

Supported Models

| Model ID | Name | Thinking Levels | Context Window | |---|---|---|---| | gemini-3.8-flash | Gemini 3.8 Flash (Antigravity) | low, medium, high | 1,048,576 | | gemini-3.7-flash | Gemini 3.7 Flash (Antigravity) | low, medium, high | 1,048,576 | | gemini-3.6-flash | Gemini 3.6 Flash (Antigravity) | low, medium, high | 1,048,576 | | gemini-3.5-flash | Gemini 3.5 Flash (Antigravity) | low, medium, high | 1,048,576 | | gemini-3.1-pro | Gemini 3.1 Pro (Antigravity) | low, high | 1,048,576 | | claude-sonnet-4-6 | Claude Sonnet 4.6 (Antigravity) | high | 200,000 | | claude-opus-4-6 | Claude Opus 4.6 (Antigravity) | high | 250,000 | | gpt-oss-120b | GPT-OSS 120B (Antigravity) | medium | 131,072 |

Installation & Setup

1. Prerequisites

You need Google OAuth credentials that have access to Antigravity (such as an active Google AI Pro plan). The plugin automatically checks for OAuth credentials in:

1. $CLOUDCODE_OAUTH_CREDS (JSON string)
2. $CLOUDCODE_OAUTH_CREDS_PATH
3. ~/.config/antigravity-oauth-proxy/oauth_creds.json
4. ~/.pi/agent/auth.json (if you already logged in using Pi)

2. Install into DeepSeek Harness Profile

Clone or link this repository into your dsh web profile:

mkdir -p ~/.dsh/profiles/web/node_modules
ln -sfn ~/Projects/dsh-llm-antigravity ~/.dsh/profiles/web/node_modules/dsh-llm-antigravity

3. Register Plugin in cordis.patch.yml

Edit ~/.dsh/profiles/web/cordis.patch.yml:

- insert:
    - id: llm-antigravity
      name: dsh-llm-antigravity
      inject:
        - llm

4. Restart dsh web

Restart your dsh web service. In the Web UI:

1. Navigate to Settings → Models.
2. Google Antigravity (AI Pro) will appear in the providers directory.
3. In any chat session, select antigravity / Gemini 3.8 Flash (Antigravity) as your active model.

Testing

Run unit tests:

node test/run.mjs

Run live request verification against Cloud Code Assist API:

node scripts/smoke-live.mjs

Acknowledgments

• Wire protocol logic and routing behaviors adapted from Rahularya01/pi-antigravity.

License

MIT