# OpenRouter · Context Atlas

> The sources OpenRouter publishes for coding agents. Fetch the llms.txt or Rules source first; fetch Full text sources only to search them, they are often several megabytes. Full catalog and instructions: https://contextatlas.dev/llms.txt

Last updated: 2026-10-23

### OpenRouter
Role: AI gateway
Signals: OPENROUTER_API_KEY env var, openrouter.ai/api/v1 base URL, model IDs such as openai/gpt-4o
- [OpenRouter llms.txt](https://openrouter.ai/llms.txt): llms.txt
- [OpenRouter MCP server setup](https://openrouter.ai/docs/guides/overview/mcp-server.md): MCP server