OpenRouter README

🚀 One MCP server for OpenRouter models 🚀

mcp-openrouter is a Python MCP server that lets Codex, Claude Code, opencode, and other MCP hosts call OpenRouter models from local stdio tools.

It exposes chat, image generation, embeddings, model listing, and model search through a small FastMCP server with retry handling, host-aware installation, and optional default model environment variables.

Install

Install the published server into every detected MCP client:

bash

uvx mcp-openrouter install --yes

Install into selected clients:

bash

uvx mcp-openrouter install --yes --clients codex,claude,opencode

Run from a local checkout:

bash

git clone https://github.com/tsilva/mcp-openrouter.git
cd mcp-openrouter
uv sync --dev
keyenv doctor
keyenv run -- uv run mcp-openrouter

mcp-openrouter with no arguments starts the stdio server. The explicit command is uv run mcp-openrouter serve.

Commands

bash

uvx mcp-openrouter install --yes                 # install into detected MCP clients
uvx mcp-openrouter install --yes --force         # replace an existing openrouter config
uvx mcp-openrouter uninstall --yes               # remove from detected MCP clients
uv run mcp-openrouter                            # run the local stdio server
uv run pytest tests/test_cli.py tests/test_client.py tests/test_config.py tests/test_installer.py tests/test_release_metadata.py tests/test_server.py
keyenv run -- uv run pytest tests/test_tools.py
uv run ruff check src/
uv run ruff format src/

Tools

Tool	Purpose
`chat`	Send a prompt or message list to an OpenRouter chat model.
`generate_image`	Generate one image and optionally save it to an absolute local path.
`embed`	Generate embeddings for a string or list of strings.
`list_models`	List models, optionally filtered by `vision`, `image_gen`, `embedding`, `tools`, or `long_context`.
`find_models`	Search model names and slugs, returning up to 20 matches.

Example MCP prompts:

text

Use openrouter chat with anthropic/claude-sonnet-4 to summarize this file
Use openrouter generate_image with google/gemini-3-pro-image-preview to create a square app icon
Use openrouter embed with mistralai/mistral-embed-2312 to embed "Hello world"
Use openrouter list_models with capability "image_gen"
Use openrouter find_models to search for "claude"

Configuration

OPENROUTER_API_KEY is required for all tool calls. For a local checkout, its .keyenv.toml maps the variable to macOS Keychain: use keyenv set OPENROUTER_API_KEY to replace it, keyenv doctor to verify it, and keyenv run -- ... to launch the server or live tests. Python still reads the value normally from os.environ.

Optional defaults make the model parameter optional for matching tools:

bash

DEFAULT_TEXT_MODEL=google/gemini-3-pro-image-preview
DEFAULT_IMAGE_MODEL=google/gemini-3-pro-image-preview
DEFAULT_CODE_MODEL=anthropic/claude-sonnet-4.5
DEFAULT_VISION_MODEL=google/gemini-3-pro-image-preview
DEFAULT_EMBEDDING_MODEL=mistralai/mistral-embed-2312

The current tools read DEFAULT_TEXT_MODEL, DEFAULT_IMAGE_MODEL, and DEFAULT_EMBEDDING_MODEL. DEFAULT_CODE_MODEL and DEFAULT_VISION_MODEL are available for client conventions. Non-secret defaults may remain in .env; the API key must not.

Notes

Python 3.10+ is required.
The published runtime command installed into hosts is uvx mcp-openrouter.
Supported installer targets are Codex, Claude Code, and opencode.
generate_image.output_path must be absolute, for example /Users/you/output.png.
Unit tests mock network calls. tests/test_tools.py requires a live OPENROUTER_API_KEY.
After changing server code, restart the MCP host so it launches a fresh server process.
Keep server.json, CHANGELOG.md, and the package version in sync before release. The Makefile release helper is make release-x.y.z.

Local MCP Development

Claude Code:

Terminal

claude mcp add openrouter --scope user -- keyenv run --manifest /path/to/mcp-openrouter/.keyenv.toml -- uv run --directory /path/to/mcp-openrouter mcp-openrouter

Codex:

bash

codex mcp add openrouter -- keyenv run --manifest /path/to/mcp-openrouter/.keyenv.toml -- uv run --directory /path/to/mcp-openrouter mcp-openrouter

opencode:

config.json

{
  "mcp": {
    "openrouter": {
      "type": "local",
      "command": ["keyenv", "run", "--manifest", "/path/to/mcp-openrouter/.keyenv.toml", "--", "uv", "run", "--directory", "/path/to/mcp-openrouter", "mcp-openrouter"],
      "enabled": true
    }
  }
}

Architecture

mcp-openrouter architecture diagram

License

MIT