An Alpaca MCP server enabling natural language trading and data access via Alpaca's Trading API. It provides real-time market data (quotes, trades, bars) and historical data across stocks, crypto, and options, plus full account, positions, and order management. Users can search assets, manage multiple watchlists, perform option strategies (including multi-leg spreads), trade crypto, and fetch market calendars and corporate actions. The server also offers market status checks, portfolio history, and detailed snapshots. It supports OAuth 2.0 passthrough authentication, allowing multi-tenant usage where each LLM chat request can carry its own user token, and forwards Authorization headers to Alpaca calls. It is designed for integration with various MCP clients (Claude Desktop, Cursor, VS Code, Claude Code, PyCharm, Gemini CLI, etc.) and supports multiple transports (stdio for local clients, HTTP/SSE for remote usage, with an HTTP transport setup). The repository provides installation methods (uvx, install.py, Docker), configuration guides, and example prompts to demonstrate trading scenarios. The MCP server can operate in live or paper trading modes and is configurable via both environment variables and client JSON configs.