cpl-mcp

MCP server for the New York State Criminal Procedure Law (CPL). Wraps the NY Senate OpenLegislation API so any MCP client can look up CPL sections by citation and search the CPL by keyword.

Installation

With uv (recommended):

uvx cpl-mcp

With pip:

pip install cpl-mcp
python -m cpl_mcp.server

Auth setup

The server requires a free OpenLegislation API key.

1. Go to https://legislation.nysenate.gov and click Sign up for an API Key.
2. Fill in the form — the key is emailed to you within a few minutes.
3. Set the environment variable before starting the server:

export NYS_LEG_API_KEY="your-key-here"

Or put it in a .env file in the project root — the server loads it automatically:

NYS_LEG_API_KEY=your-key-here

Claude Desktop config

Add the following to claude_desktop_config.json (~/Library/Application Support/Claude/ on macOS, %APPDATA%\Claude\ on Windows):

{
  "mcpServers": {
    "cpl": {
      "command": "uvx",
      "args": ["cpl-mcp"],
      "env": {
        "NYS_LEG_API_KEY": "your-key-here"
      }
    }
  }
}

If you prefer a local checkout instead of uvx:

{
  "mcpServers": {
    "cpl": {
      "command": "uv",
      "args": [
        "--directory", "/absolute/path/to/cpl-mcp",
        "run", "python", "-m", "cpl_mcp.server"
      ],
      "env": {
        "NYS_LEG_API_KEY": "your-key-here"
      }
    }
  }
}

Environment variables

Variable	Required	Description
NYS_LEG_API_KEY	Yes	OpenLegislation API key. Get one at https://legislation.nysenate.gov.

Tools

Tool	Description
cpl_lookup_section	Retrieve the full text of a CPL section or article by citation (e.g. 245.20, A245).
cpl_search	Full-text keyword search across the CPL. Returns a ranked list of matching sections with snippets.

cpl_lookup_section

Use when you know the section number. Accepts flexible citation formats — CPL § 245.20, section 245.20, and 245.20 all resolve to the same location. Returns the statute text, active date, structural breadcrumb (article/title parents), and a link to the official nysenate.gov page.

cpl_search

Use when searching by topic rather than citation. Supports pagination via limit (1–50, default 10) and offset (1-based, default 1).

Both tools accept a response_format parameter: "markdown" (default, human-readable) or "json" (machine-readable, useful for chaining tools).

Running locally

# one-shot lookup — no MCP client needed
python -m cpl_mcp.server --selftest 245.20

# one-shot lookup + keyword search
python -m cpl_mcp.server --selftest 245.20 --search "speedy trial"

# HTTP transport for debugging (listens on 127.0.0.1:8000)
python -m cpl_mcp.server --http