gemini-claude-bridge

gemini-claude-bridge

Production-grade **Gemini ↔ Anthropic Claude** protocol converter.

Two ways to use it:

1. Claude Code Proxy — drop-in replacement, ANTHROPIC_BASE_URL=http://localhost:8082 claude
2. Python Library — pip install gemini-claude-bridge, convert requests/responses in your own app

Why this exists

LiteLLM has 3 open bugs in Gemini↔Claude conversion that break real-world tool calling:

Problem	LiteLLM Issue	This library
Multi-turn tool calling + thinking crashes	#17949 (3+ months)	thoughtSignature file persistence + missing-signature recovery
tool_result images silently dropped	#23712	Image separation + functionResponse.parts nesting
No streaming tool arguments	#22206	partialArgs state machine + incremental JSON delta

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Usage 1: Claude Code Proxy

Quick start

pip install "gemini-claude-bridge[proxy]"

# Start proxy (default port 8082)
GEMINI_API_KEY=your-key python -m examples.proxy_server

# In another terminal — use Claude Code with Gemini backend
ANTHROPIC_BASE_URL=http://localhost:8082 ANTHROPIC_API_KEY=dummy claude

Docker

# .env file
GEMINI_API_KEY=your-key
BIG_MODEL=gemini-2.5-pro
SMALL_MODEL=gemini-2.5-flash

docker compose up -d

ANTHROPIC_BASE_URL=http://localhost:8082 claude

Configuration

Env var	Default	Description
GEMINI_API_KEY	(required)	Google AI Studio API key
GEMINI_API_BASE_URL	https://generativelanguage.googleapis.com	Gemini API base URL (for custom endpoints / Vertex)
BIG_MODEL	gemini-2.5-flash	Model for opus/sonnet requests
SMALL_MODEL	gemini-2.5-flash	Model for haiku requests

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