Tools

10 tools covering the full Open States v3 API surface — bills, legislators, committees, events, and jurisdictions:

openstates_search_bills

Search state legislative bills with rich filtering and inline related data.

• Full-text search across bill titles, abstracts, and text (q)
• Either jurisdiction or q is required by the input schema — a call carrying neither fails schema validation, and pairing them is the reliable form, since a q-only search spans all 56 jurisdictions and times out upstream for a common term
• Filter by jurisdiction (state name, two-letter abbreviation, or OCD-ID), session, chamber, classification, subject tags, and sponsor
• Sort by latest action, first action, or update time — use sort=latest_action_desc for bills currently moving through the legislature
• include parameter requests sponsorships, actions, votes, abstracts, versions, and related bills inline — eliminates follow-up openstates_get_bill calls for most research workflows
• Sponsors carry linked person records (OCD person ID + name) when available, so a sponsor chains onward by ID rather than by name match
• Every result carries openstates_url (citable page) and updated_at (the field the default sort=updated_desc orders by)
• action_since, updated_since, and created_since date filters for change-tracking
• Pagination up to 20 results per page
• Empty-result recovery: appliedFilters echoes every filter the query was issued with and the notice names each one that narrowed it, so a zero-result answer identifies its own cause. A jurisdiction that matches no covered jurisdiction is called out by name — Open States answers an unrecognized one with zero bills rather than an error

openstates_get_bill

Fetch complete bill detail by OCD ID or path lookup.

• Two lookup modes: openstates_id (OCD bill ID from search results, preferred) or the three-part path jurisdiction + session + bill_id
• Accepts bill identifiers in legislature format (e.g., HB 1000, SB 42)
• include=votes returns full vote tallies and per-legislator positions
• include=versions,documents provides links to bill text and fiscal notes
• Sponsors carry linked person records (OCD person ID + name) when available

openstates_search_people

Search legislators and officials within one jurisdiction by name, chamber, or district, or fetch specific people by OCD person ID.

• Either jurisdiction or id is required by the input schema — a search spanning all 56 jurisdictions exceeds the upstream timeout, name-only searches included, so a call carrying neither fails schema validation. Use openstates_list_jurisdictions to pick a jurisdiction, or openstates_get_legislators_by_location when you have coordinates but no state
• id takes OCD person IDs and returns exactly those people, so it needs no jurisdiction alongside it. It resolves the IDs that search results, openstates_get_bill sponsorships, and openstates_get_committee memberships hand back — several in one call, since upstream /people accepts id repeatedly and offers no per-person detail route
• Case-insensitive substring matching on name
• org_classification targets a role type: upper (Senate), lower (House/Assembly), executive (governors and executive officials), legislature (every legislator — both chambers merged into one paginated set, all upper members then all lower)
• Omitting org_classification is not equivalent to legislature — it returns every officeholder, executive officials included
• include=offices returns phone, fax, and mailing address
• include=links returns website and social media links
• Every result carries the member's official headshot URL (image) when published, and the OCD division their district maps to (current_role.division_id)

openstates_get_legislators_by_location

Find every legislator representing a geographic coordinate, across both tiers of government.

• Pass decimal-degree latitude/longitude to get the state senators and representatives for that location, plus its two US Senators and its US Representative
• jurisdiction.classification separates the tiers: "state" is a state legislature, "country" is the US Congress. current_role.org_classification does not — it is upper/lower for a US Senator exactly as for a state senator
• stateCount and federalCount report the split, and the rendered text labels each legislator's tier
• Useful for constituent-to-representative matching, address-based policy research, and electoral boundary analysis
• Does not geocode addresses — the caller must provide coordinates
• Returns a coverage note when no legislators are found (e.g., coordinates outside US boundaries)

openstates_list_jurisdictions and openstates_get_jurisdiction

Discover and look up jurisdiction coverage metadata.

• openstates_list_jurisdictions returns all 56 jurisdictions (50 states, DC, and 5 US territories) in a single default call — the pages are merged server-side, since the upstream per_page ceiling of 52 no longer covers the full set
• include=legislative_sessions returns all historical and current session identifiers — required before filtering bill searches by session, since formats vary widely by state (e.g., 2025, 2025-2026, 2025rs, 2025s1)
• openstates_get_jurisdiction fetches one jurisdiction by OCD-ID, state name, or two-letter abbreviation

Committee and event tools (experimental)

openstates_search_committees, openstates_get_committee, openstates_search_events, and openstates_get_event are experimental — Open States is actively working to restore committee support and most states do not publish event data. Empty results may indicate the state lacks data, not that no committees or events exist. The two search tools (openstates_search_committees and openstates_search_events) include a coverageNote field in their output documenting this limitation, and both require a jurisdiction in their input schema — a request spanning all 56 exceeds the upstream timeout, so a call that omits it fails schema validation.

Resources and prompts

All resource data is also reachable via tools. Use openstates_get_jurisdiction for programmatic jurisdiction lookups; the resource is useful for injecting jurisdiction context as stable reference material.

Features

Built on @cyanheads/mcp-ts-core:

• Declarative tool, resource, and prompt definitions — single file per primitive, framework handles registration and validation
• Unified error handling — handlers throw, framework catches, classifies, and formats
• Pluggable auth: none, jwt, oauth
• Swappable storage backends: in-memory, filesystem, Supabase, Cloudflare KV/R2/D1
• Structured logging with optional OpenTelemetry tracing
• STDIO and Streamable HTTP transports

Open States-specific:

• Full Open States v3 API coverage: bills, people, committees, events, and jurisdictions
• Dual lookup modes on bill and committee fetchers (OCD ID or structured path)
• Geo-based legislator lookup via the Open States people-by-geo endpoint
• Server-level instructions prime the agent with session discovery workflow and include parameter strategy before any tool calls

Agent-friendly output:

• Empty-result recovery: tools echo the applied filters and suggest how to broaden when no results are returned
• Experimental coverage notes on committee and event tools — agents can surface these to users rather than returning silent empty results
• include parameter pattern across all search and get tools — avoids N+1 follow-up calls for common research workflows (e.g., include=sponsorships,actions on openstates_search_bills)

Getting started

Requires an Open States API key — register free at open.pluralpolicy.com.

Add the following to your MCP client configuration file:

{
  "mcpServers": {
    "openstates-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/openstates-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info",
        "OPENSTATES_API_KEY": "your-api-key"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "openstates-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/openstates-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info",
        "OPENSTATES_API_KEY": "your-api-key"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "openstates-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "-e", "MCP_TRANSPORT_TYPE=stdio",
        "-e", "OPENSTATES_API_KEY=your-api-key",
        "ghcr.io/cyanheads/openstates-mcp-server:latest"
      ]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 OPENSTATES_API_KEY=your-key bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.3.0 or higher (or Node.js v24+).
• An Open States API key — register free at open.pluralpolicy.com.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/openstates-mcp-server.git

2. Navigate into the directory:

cd openstates-mcp-server

3. Install dependencies:

bun install

4. Configure environment:

cp .env.example .env
# edit .env and set OPENSTATES_API_KEY

Configuration

All configuration is validated at startup via Zod schemas in src/config/server-config.ts. Key environment variables:

See .env.example for the full list of optional overrides.

Running the server

Local development

• Build and run the production version:

  sh

  Copy

  # One-time build
  bun run rebuild
  
  # Run the built server
  bun run start:stdio
  # or
  bun run start:http
  

• Run checks and tests:

  sh

  Copy

  bun run devcheck   # Lint, format, typecheck, security
  bun run test       # Vitest test suite
  bun run lint:mcp   # Validate MCP definitions against spec
  

Docker

docker build -t openstates-mcp-server .
docker run --rm -e OPENSTATES_API_KEY=your-key -e MCP_TRANSPORT_TYPE=http -p 3010:3010 openstates-mcp-server

The Dockerfile defaults to HTTP transport, explicitly sets MCP_SESSION_MODE=stateless, and logs to /var/log/openstates-mcp-server. OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging, ctx.state for tenant-scoped storage
• Register new tools and resources via the arrays in src/index.ts
• Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields

Contributing

Issues and pull requests are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.