LegiScan MCP Server

A Model Context Protocol (MCP) server that gives terminal agents structured access to the LegiScan API for legislative data from all 50 US states and Congress.

Built for research workflows where you direct an agent (Codex, Claude Code, Claude Desktop, etc.) to gather bill history, sponsor context, and voting records quickly.

Features

• 10 Streamlined MCP Tools optimized for legislative research workflows
• Composite tools that batch multiple API calls (90%+ reduction in API usage)
• Full TypeScript type definitions for all API responses
• Bill number normalization (handles AB 858, AB858, AB-858 formats)
• Input validation guardrails for state codes, legislator name queries, and large bill batches

Installation

From npm (Recommended)

npm install -g legiscan-mcp-server

From Source

git clone https://github.com/sh-patterson/legiscan-mcp.git
cd legiscan-mcp
npm install
npm run build

Setup

1. Get a LegiScan API Key

1. Create a free account at LegiScan
2. Register for API access at https://legiscan.com/legiscan
3. Copy your API key

2. Add to Your MCP-Capable Agent

Add this server to whatever MCP host your terminal agent uses.

Claude Desktop config paths:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

For other MCP clients (Codex CLI, Claude Code, etc.), add the same mcpServers.legiscan entry in that client's MCP config file.

Using npx (Recommended)

{
  "mcpServers": {
    "legiscan": {
      "command": "npx",
      "args": ["-y", "legiscan-mcp-server"],
      "env": {
        "LEGISCAN_API_KEY": "your_api_key_here"
      }
    }
  }
}

Using local installation

{
  "mcpServers": {
    "legiscan": {
      "command": "node",
      "args": ["/path/to/legiscan-mcp-server/dist/index.js"],
      "env": {
        "LEGISCAN_API_KEY": "your_api_key_here"
      }
    }
  }
}

Available Tools

Composite Tools (High-Level Research)

Tool	Description
legiscan_find_legislator	Find a legislator's people_id by name. Supports partial matching.
legiscan_get_legislator_votes	Get how a legislator voted on multiple bills in one call.
legiscan_get_primary_authored	Get only bills where legislator is primary author (not co-sponsor).

Bills

Tool	Description
legiscan_get_bill	Get detailed bill info (sponsors, history, votes, texts)
legiscan_find_bill_by_number	Find bill by number (handles AB 858, AB858, AB-858)
legiscan_get_roll_call	Get vote details with individual legislator votes

People

Tool	Description
legiscan_get_person	Get legislator info with third-party IDs (VoteSmart, OpenSecrets, etc.)
legiscan_get_session_people	Get all legislators active in a session

Search

Tool	Description
legiscan_search	Full-text search across legislation

Sessions

Tool	Description
legiscan_get_session_list	List available legislative sessions by state

Researcher Workflow (Terminal Agent)

1. Start with a scoped request

Give your agent a goal, state, timeframe, and output format.

Example prompt:

Use the LegiScan MCP tools to find major California housing bills in the current session.
Return: bill number, title, latest action date, top sponsors, and whether there was a close roll-call vote (margin <= 5).

2. Ask the agent to follow a tool sequence

For high-quality results, tell the agent to do this order:

1. legiscan_get_session_list to identify the correct session.
2. legiscan_search or legiscan_find_bill_by_number to locate target bills.
3. legiscan_get_bill for sponsor/history/vote references.
4. legiscan_get_roll_call for individual vote details.
5. legiscan_get_person only when legislator enrichment is needed.

3. Reuse composite tools for analyst workflows

These cut tool-call volume and simplify instructions to your agent:

• legiscan_find_legislator: get people_id from a name query.
• legiscan_get_primary_authored: separate primary-authored from co-sponsored bills.
• legiscan_get_legislator_votes: pull vote positions across many bills in one request.

Prompt Templates

A) Opposition research on one legislator

Use LegiScan MCP for Texas.
1) Find legislator "Jane Smith".
2) List all primary-authored bills in the current session.
3) For these bills, summarize topic area and latest status.
4) Then check votes on SB 12, HB 301, and SB 455, and show how the legislator voted.

B) Bill tracking brief for an issue area

Use LegiScan MCP to track "climate resilience" bills in New York.
Focus on current session only.
Return top 15 bills by relevance with bill number, title, last action, sponsor party, and any recorded roll calls.

C) Scorecard support workflow

For California session 2172, resolve bill numbers AB 858, SB 525, SB 616, SB 399.
For each bill, fetch details and any roll calls.
Then report vote positions for people_id values 21719, 23214, and 25359.
Output as a table suitable for CSV export.

API Call Reduction

The composite tools dramatically reduce API calls for common workflows:

Workflow	Without Composites	With Composites
Get votes for 1 legislator on 10 bills	~80 calls	1 call
Filter primary authored from 150 sponsored	~150 calls	1 call
Find legislator by name	2 calls	1 call

Research Tips

• State codes are validated as two-letter strings and uppercased automatically (ca → CA). Invalid codes like ZZ pass local validation but return an API error from LegiScan.
• Always pin state and session in your prompt to reduce ambiguous results.
• Ask the agent to show bill_id, roll_call_id, and people_id in intermediate output so you can audit traceability.
• For legislator search, provide at least a first and last name (name input must be at least 2 characters).
• legiscan_get_legislator_votes accepts up to 100 bill_ids per request; split larger jobs into chunks.
• Ask for final outputs in a table/CSV-ready shape if you plan downstream analysis.

Development

npm run build        # Compile TypeScript
npm run typecheck    # Type-check src + tests
npm test             # Run deterministic unit tests (no API key)
npm run test:live    # Run live API integration tests (requires API key)
npm run lint         # Check for lint errors
npm run format       # Format code with Prettier

Testing Modes

• npm test / npm run test:unit: Fast deterministic tests with mocked network calls.
• npm run test:live: Real LegiScan API integration tests. Requires LEGISCAN_API_KEY.

API Limits

• Free public API keys have a 30,000 queries per month limit
• Composite tools batch requests (10 concurrent max) to avoid rate limits
• The composite tools help you stay within limits by reducing total API calls

Docker

Build the container image locally:

docker build -t legiscan-mcp .

Run it with your API key provided at runtime:

docker run --rm -i \
  -e LEGISCAN_API_KEY=your-api-key-here \
  legiscan-mcp

Releases

Glama checks expect a GitHub release. Create and publish a tag such as v1.0.0 after pushing changes.

License

MIT - see LICENSE for details.