AG (Antigravity) Local Bridge

Exposes your running Antigravity instance as a local OpenAI-compatible API on localhost:11435.

Use your Antigravity subscription with any tool that speaks OpenAI — opencode, aider, continue.dev, or plain curl.

How it Works

Your tool → HTTP :11435 → VS Code extension → Antigravity sidecar (ConnectRPC) → Cloud AI

The extension runs inside Antigravity's VS Code process, discovers the sidecar via process inspection, intercepts CSRF tokens from Antigravity's own traffic, and proxies your requests through the same authenticated channel Antigravity uses internally.

Features

Multi-Protocol API — drop-in compatible with OpenAI (/v1/chat/completions), Anthropic (/v1/messages), and Gemini (/v1beta/models/...)
3-Way Streaming Strategy — configurable smart (instant low-TTFB pseudo-streaming for chat + raw for tools), raw (pure LLM completions & swarm), or cascade
Multi-Sidecar Swarm — automatic round-robin load balancing and quota pooling across multiple Google accounts
Multimedia Input Support — images, audio, video, and files forwarded through Antigravity's media channels
Function Calling & Tools — full support for client-side tool calling and structured outputs
Workspace-Aware — automatically detects and applies workspace context via x-workspace-dir / x-workspace-uri headers

Available Models

Model ID	Description
`antigravity-claude-sonnet-4-6`	Claude Sonnet 4.6 with Thinking (default)
`antigravity-claude-opus-4-6-thinking`	Claude Opus 4.6 with Thinking
`antigravity-claude-opus-5-5-high`	Claude Opus 5.5 — High thinking
`antigravity-claude-opus-5-5-medium`	Claude Opus 5.5 — Medium thinking
`antigravity-claude-opus-5-5-low`	Claude Opus 5.5 — Low thinking
`antigravity-claude-sonnet-5-5-high`	Claude Sonnet 5.5 — High thinking
`antigravity-claude-sonnet-5-5-medium`	Claude Sonnet 5.5 — Medium thinking
`antigravity-claude-sonnet-5-5-low`	Claude Sonnet 5.5 — Low thinking
`antigravity-gemini-4-argon-high`	Gemini 4 Argon — High thinking
`antigravity-gemini-4-argon-medium`	Gemini 4 Argon — Medium thinking
`antigravity-gemini-4-argon-low`	Gemini 4 Argon — Low thinking
`antigravity-gemini-4-hydrogen-xhigh`	Gemini 4 Hydrogen — XHigh thinking
`antigravity-gemini-4-hydrogen-high`	Gemini 4 Hydrogen — High thinking
`antigravity-gemini-4-hydrogen-medium`	Gemini 4 Hydrogen — Medium thinking
`antigravity-gemini-4-hydrogen-low`	Gemini 4 Hydrogen — Low thinking
`antigravity-gemini-4-carbon-high`	Gemini 4 Carbon — High thinking
`antigravity-gemini-4-carbon-medium`	Gemini 4 Carbon — Medium thinking
`antigravity-gemini-4-carbon-low`	Gemini 4 Carbon — Low thinking
`antigravity-gemini-4-carbon`	Gemini 4 Carbon
`antigravity-gemini-pro-orchestrator-g1-pro`	Orchestrator (Argon)
`antigravity-gemini-3.8-flash-high`	Gemini 3.8 Flash — High thinking
`antigravity-gemini-3.8-flash-medium`	Gemini 3.8 Flash — Medium thinking
`antigravity-gemini-3.8-flash-low`	Gemini 3.8 Flash — Low thinking
`antigravity-gemini-3.7-flash-high`	Gemini 3.7 Flash — High thinking
`antigravity-gemini-3.7-flash-medium`	Gemini 3.7 Flash — Medium thinking
`antigravity-gemini-3.7-flash-low`	Gemini 3.7 Flash — Low thinking
`antigravity-gemini-3.6-flash-high`	Gemini 3.6 Flash — High thinking
`antigravity-gemini-3.6-flash-medium`	Gemini 3.6 Flash — Medium thinking
`antigravity-gemini-3.6-flash-low`	Gemini 3.6 Flash — Low thinking
`antigravity-gemini-3.5-flash`	Gemini 3.5 Flash — High thinking
`antigravity-gemini-3.5-flash-medium`	Gemini 3.5 Flash — Medium thinking
`antigravity-gemini-3.5-flash-low`	Gemini 3.5 Flash — Low thinking
`antigravity-gemini-3-flash`	Gemini 3 Flash
`antigravity-gemini-3.1-pro-high`	Gemini 3.1 Pro — High thinking
`antigravity-gemini-3.1-pro-low`	Gemini 3.1 Pro — Low thinking
`antigravity-gpt-oss-120b`	GPT-OSS 120B Medium

Short aliases: All models can also be referenced with intuitive short names like gemini-3.8, gemini-3.8-flash, gemini-3.7, gemini-3.7-flash, gemini-3.6-flash, gemini-3.5-flash, gemini-3.1-pro, claude-sonnet-4-6, claude-opus-4-6-thinking, etc.

Installation

From Open VSX (recommended)

Open Antigravity
Go to Extensions (Ctrl+Shift+X)
Search for "AG Local Bridge" by marcodiniz
Click Install
Reload Antigravity (Ctrl+Shift+P → Developer: Reload Window)

Manual install

Clone into your Antigravity extensions directory:

# Windows
git clone https://github.com/marcodiniz/ag-local-bridge "%USERPROFILE%\.antigravity\extensions\ag-local-bridge-1.0.0-universal"

# macOS / Linux
git clone https://github.com/marcodiniz/ag-local-bridge ~/.antigravity/extensions/ag-local-bridge-1.0.0-universal

Reload Antigravity (Ctrl+Shift+P → Developer: Reload Window)

Verify

Look for "AG Local Bridge" in the Output panel — you should see:

✅ Server running on http://localhost:11435

Usage

With opencode

Add to ~/.config/opencode/opencode.json:

{
  "provider": {
    "ag-local-bridge": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "AG Local Bridge",
      "options": {
        "baseURL": "http://localhost:11435/v1",
        "apiKey": "local"
      },
      "models": {
        "antigravity-claude-sonnet-4-6": {
          "name": "Claude Sonnet 4.6 (Antigravity)",
          "modalities": { "input": ["text", "image", "audio", "video", "file"], "output": ["text"] },
          "limit": { "context": 200000, "output": 64000 }
        },
        "antigravity-claude-opus-4-6-thinking": {
          "name": "Claude Opus 4.6 Thinking (Antigravity)",
          "modalities": { "input": ["text", "image", "audio", "video", "file"], "output": ["text"] },
          "limit": { "context": 200000, "output": 64000 }
        },
        "antigravity-gemini-3.1-pro-high": {
          "name": "Gemini 3.1 Pro High (Antigravity)",
          "modalities": { "input": ["text", "image", "audio", "video", "file"], "output": ["text"] },
          "limit": { "context": 1048576, "output": 65535 }
        },
        "antigravity-gemini-3.1-pro-low": {
          "name": "Gemini 3.1 Pro Low (Antigravity)",
          "modalities": { "input": ["text", "image", "audio", "video", "file"], "output": ["text"] },
          "limit": { "context": 1048576, "output": 65535 }
        },
        "antigravity-gemini-3-flash": {
          "name": "Gemini 3 Flash (Antigravity)",
          "modalities": { "input": ["text", "image", "audio", "video", "file"], "output": ["text"] },
          "limit": { "context": 1048576, "output": 65536 }
        },
        "antigravity-gpt-oss-120b": {
          "name": "GPT-OSS 120B Medium (Antigravity)",
          "modalities": { "input": ["text", "image", "audio", "video", "file"], "output": ["text"] },
          "limit": { "context": 128000, "output": 16384 }
        }
      }
    }
  }
}

Then select ag-local-bridge/antigravity-claude-sonnet-4-6 as your model.

Media support: The modalities field enables image/audio/video/file input in clients that expose those attachments. Text-only requests use the faster raw inference path; requests with media use the Antigravity Cascade media channel.

With curl

# List models
curl http://localhost:11435/v1/models

# Chat completion
curl http://localhost:11435/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "antigravity-claude-sonnet-4-6",
    "messages": [{"role": "user", "content": "Hello!"}],
    "stream": false
  }'

# Streaming
curl http://localhost:11435/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "antigravity-gemini-3.1-pro-high",
    "messages": [{"role": "user", "content": "Hello!"}],
    "stream": true
  }'

# With image (base64 data URL)
curl http://localhost:11435/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "antigravity-claude-sonnet-4-6",
    "messages": [{"role": "user", "content": [
      {"type": "text", "text": "What do you see?"},
      {"type": "image_url", "image_url": {"url": "data:image/png;base64,iVBOR..."}}
    ]}],
    "stream": false
  }'

# Responses API
curl http://localhost:11435/v1/responses \
  -H "Content-Type: application/json" \
  -d '{
    "model": "antigravity-claude-sonnet-4-6",
    "input": "Hello from the Responses API"
  }'

With any OpenAI-compatible client

Base URL: http://localhost:11435/v1
API Key:  anything (not validated)

API Endpoints

OpenAI Endpoints

Method	Path	Description
`GET`	`/v1/models`	List available models in OpenAI format
`POST`	`/v1/chat/completions`	Chat completion (streaming & non-streaming)
`POST`	`/v1/responses`	OpenAI Responses API adapter

Anthropic Endpoints

Method	Path	Description
`POST`	`/v1/messages`	Anthropic Messages API (streaming & tools)
`POST`	`/v1/messages/count_tokens`	Preflight token count mock (for Claude CLI)

Gemini Endpoints

Method	Path	Description
`GET`	`/v1beta/models`	List models in Gemini format
`POST`	`/v1beta/models/:model:generateContent`	Gemini Native generateContent
`POST`	`/v1beta/models/:model:streamGenerateContent`	Gemini Native streaming endpoint

Utility & Debug Endpoints

Method	Path	Description
`POST`	`/v1/proxy`	Forward arbitrary RPC to sidecar
`GET`	`/v1/debug`	Debug info (sidecar ports, CSRF, captures)

Multimedia Support

Media sent via OpenAI chat content parts or Responses input items is handled as follows:

Base64 data URLs (data:image/png;base64,..., data:audio/wav;base64,..., etc.) — decoded and forwarded inline
Remote URLs (https://...) — downloaded, then forwarded inline
File URIs (file:///C:/path/to/media.mp4) — read directly from disk
Responses items (input_image, input_audio, input_file) — converted to the same media channel

The sidecar ultimately decides which model/media combinations are accepted. Unsupported media types will surface as upstream provider errors.

Workspace Context

Pass workspace context via HTTP headers:

Header	Description
`x-workspace-dir`	Absolute filesystem path (e.g. `C:\code\myproject`)
`x-workspace-uri`	File URI (e.g. `file:///C:/code/myproject`)

When set, the bridge switches the active VS Code workspace folder before creating a Cascade, ensuring the agent operates in the correct project context.

Architecture

The extension uses a 2-tier fallback strategy:

Tier 1 — Sidecar ConnectRPC (preferred): Discovers the Antigravity sidecar process, connects via HTTP/2 with CSRF authentication, and uses the Cascade API (StartCascade → SendUserCascadeMessage → poll GetCascadeTrajectory). Conversations are multiplexed and the active workspace is auto-detected.
Tier 2 — Command Dispatch: Last resort — fires the message through antigravity.executeCascadeAction.

Commands

Command	Description
`AG Local Bridge: Start Server`	Start the HTTP server
`AG Local Bridge: Stop Server`	Stop the HTTP server
`AG Local Bridge: Show Status`	Display connection status
`AG Local Bridge: Probe Sidecar`	Test sidecar connectivity
`AG Local Bridge: List Available LM Models`	List configured models and sidecar status
`AG Local Bridge: List Available Chat Commands (Debug)`	List chat commands available for debugging

Configuration

Setting	Default	Description
`agLocalBridge.port`	`11435`	HTTP server port
`agLocalBridge.logRequests`	`false`	Log request/response details
`agLocalBridge.streamingMode`	`"smart"`	Streaming strategy: `'smart'` (low-TTFB Cascade pseudo-streaming for chat, Raw for tools), `'raw'` (strictly GetModelResponse unary inference), or `'cascade'` (forced trajectory delta streaming)

Requirements

Antigravity installed and running
Active Antigravity subscription (Free/Pro/Teams/Enterprise)

Contributing

We use a beta → master release flow:

Branch	Role	Publishes as
`beta`	Default / development	Pre-release
`master`	Stable releases only	Stable

Fork & branch off beta (the default branch).
Open your PR against beta — GitHub will target it automatically.
Once merged, a pre-release is published to Open VSX for beta testers.
When a beta build is ready for general availability, the maintainer merges beta → master to cut a stable release.

Note: master is protected — direct pushes are not allowed. All changes flow through beta first.

License

MIT

Name		Name	Last commit message	Last commit date
.agents/workflows		.agents/workflows
.github/workflows		.github/workflows
assets		assets
scripts		scripts
src		src
test		test
.editorconfig		.editorconfig
.gitignore		.gitignore
.prettierignore		.prettierignore
.prettierrc		.prettierrc
.vscodeignore		.vscodeignore
CHANGELOG.md		CHANGELOG.md
GEMINI.md		GEMINI.md
LICENSE		LICENSE
README.md		README.md
eslint.config.js		eslint.config.js
icon.png		icon.png
package-lock.json		package-lock.json
package.json		package.json

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AG (Antigravity) Local Bridge

How it Works

Features

Available Models

Installation

From Open VSX (recommended)

Manual install

Verify

Usage

With opencode

With curl

With any OpenAI-compatible client

API Endpoints

OpenAI Endpoints

Anthropic Endpoints

Gemini Endpoints

Utility & Debug Endpoints

Multimedia Support

Workspace Context

Architecture

Commands

Configuration

Requirements

Contributing

License

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AG (Antigravity) Local Bridge

How it Works

Features

Available Models

Installation

From Open VSX (recommended)

Manual install

Verify

Usage

With opencode

With curl

With any OpenAI-compatible client

API Endpoints

OpenAI Endpoints

Anthropic Endpoints

Gemini Endpoints

Utility & Debug Endpoints

Multimedia Support

Workspace Context

Architecture

Commands

Configuration

Requirements

Contributing

License

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