Openstates MCP Server README

Overview

US state legislatures from Open States: all 50 states, DC, and 5 US territories. Search bills, legislators, committees, and events, and find who represents any location.

Tools

Resources

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.

Prompts

Skills

Plugin installs and the .mcpb bundle pick it up from skills/; MCP clients that support the Skills extension receive it from the server.

Capability reference

openstates_search_bills _tool

• Either jurisdiction or q is required by the schema — a q-only search spans all 56 jurisdictions and exceeds the upstream timeout for a common term, so pairing them is the reliable form
• Filters: session, chamber (upper/lower), classification, subject tags, sponsor, sponsor_classification, and action_since/updated_since/created_since ISO 8601 date filters
• include inlines sponsorships, actions, votes, abstracts, versions, documents, and related bills — avoids follow-up openstates_get_bill calls
• sort defaults to updated_desc; sort=latest_action_desc surfaces bills currently moving; pagination up to 20 per page (default 10)
• Empty-result notice echoes every applied filter and names the jurisdiction by name when it isn't recognized

openstates_get_bill _tool

• Lookup by openstates_id (preferred) or the three-part path jurisdiction + session + bill_id; a call missing both fails with missing_lookup_params
• openstates_id is ocd-bill/<uuid> copied from openstates_search_bills (case and surrounding whitespace are normalized); a <jurisdiction>/<session>/<bill_id> path is also accepted. Any other value fails locally with invalid_openstates_id, with no upstream call
• Accepts legislature-format bill identifiers (e.g., HB 1000, SB 42)
• include inlines sponsorships, actions, votes, versions, documents, abstracts, other titles/identifiers, and related bills
• not_found when a well-formed ID or a three-part path resolves to nothing

openstates_search_people _tool

• Either jurisdiction or id (OCD person IDs) is required — an unscoped search exceeds the upstream timeout even for a name-only query
• id resolves any number of specific OCD person IDs in one call — the IDs that bill sponsorships and committee memberships hand back — and needs no jurisdiction alongside it
• org_classification: upper/lower/executive/legislature (every legislator — both chambers, or the single body in Nebraska and DC; executive officials excluded); omitting it returns every officeholder including executives
• Case-insensitive substring name match, plus district; include adds offices, links, other_names, other_identifiers, sources
• Party is reported on every result but cannot be filtered on
• Pagination up to 20 per page

openstates_get_legislators_by_location _tool

• Pass decimal-degree latitude/longitude; does not geocode addresses
• Returns both government tiers in one call: state legislators plus the coordinate's two US Senators and one US Representative
• jurisdiction.classification (state vs country) is the tier discriminator — current_role.org_classification is not, since it's upper/lower for a US Senator exactly as for a state senator
• stateCount/federalCount enrichment fields report the tier split
• Out-of-range coordinates fail as invalid_coordinate; a location with no coverage returns an empty-result notice

openstates_search_committees _tool

• jurisdiction is required — the schema rejects an all-states request
• Filter by classification (committee/subcommittee) and chamber (a chamber filter omits joint committees); parent scopes to one committee's subcommittees
• include=memberships returns the full roster with member roles
• Experimental: Open States is working to restore committee support and not all states have coverage — the output's coverageNote field always documents this
• Pagination up to 20 per page

openstates_get_committee _tool

• Fetch by OCD committee_id (from openstates_search_committees)
• include=memberships returns the roster; include=links/sources add reference URLs
• Experimental — not all states have committee data; not_found when the ID doesn't exist

openstates_search_events _tool

• jurisdiction is required — the events endpoint has no all-states search
• after/before scope to an ISO 8601 date range; require_bills=true filters to events with a bill on the agenda
• include=agenda,participants returns full meeting context
• Experimental: most states don't publish event data — an empty unfiltered result may mean no coverage, not no events; an empty filtered result (require_bills, after, before) names those filters in its notice
• Pagination up to 20 per page

openstates_get_event _tool

• Fetch by OCD event_id (from openstates_search_events)
• include adds agenda, participants, links, media, and documents
• Experimental — event coverage is limited; not_found when the ID doesn't exist

openstates_list_jurisdictions _tool

• Returns all 56 jurisdictions (50 states, DC, and 5 US territories) in one default call — pages are merged server-side, since the upstream per_page ceiling of 52 no longer covers the full set
• classification filter defaults to state
• include=legislative_sessions returns every historical and current session identifier — required before filtering bill searches by session, since formats vary by state (e.g., 2025, 2025-2026, 2025rs, 2025s1)
• include=organizations/latest_runs add chamber/executive-body and scraper-run metadata

openstates_get_jurisdiction _tool

• Fetch one jurisdiction by OCD-ID, state name, or two-letter abbreviation
• include=legislative_sessions returns all session identifiers with date ranges
• not_found when the identifier doesn't resolve

openstates://jurisdiction/{+jurisdiction_id} _resource

• jurisdiction_id accepts the raw OCD ID (slashes intact) as openstates_list_jurisdictions returns it, a state name (multi-word allowed), or a two-letter abbreviation; percent-encoded forms are decoded once, and a malformed escape is a validation error
• Returns jurisdiction metadata as application/json: current legislative sessions, coverage dates, bill/people update timestamps
• Always includes legislative_sessions — use to prime session identifiers without a tool call
• not_found when the identifier doesn't resolve; rate_limited when the shared key's request cap is reached

openstates_bill_research _prompt

• Arguments: jurisdiction, session, bill_id — all required
• Returns one user message directing a structured research brief: overview, sponsors, legislative history, vote record, related legislation, bill text, and a passage assessment

openstates_legislator_profile _prompt

• Arguments: name, jurisdiction — both required
• Returns one user message directing a structured profile: identity/role, sponsored legislation, committee assignments, voting record, and a summary

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

Open States-specific:

• Full Open States v3 API coverage: bills, people, committees, events, and jurisdictions
• Dual lookup modes on the bill fetcher (OCD ID or jurisdiction + session + bill identifier)
• Geo-based legislator lookup via the Open States people-by-geo endpoint, spanning both state and federal tiers
• Server-level instructions prime the agent with session-discovery workflow and include parameter strategy before any tool call
• Per-key request budgeting (OPENSTATES_DAILY_REQUEST_BUDGET) and a two-tier timeout ladder guard the shared upstream key
• Every tool and the jurisdiction resource can fail with rate_limited when Open States' per-minute or daily cap, or the server's own daily budget, is reached: the error is retryable, carries retryAfter (seconds), and costs one attempt rather than a retry loop

Agent-friendly output:

• Empty-result recovery: search tools echo the applied filters and suggest how to broaden when no results are returned
• Experimental coverage notes (coverageNote) on committee and event tools — surfaces the limitation instead of a silent empty result
• include parameter pattern across all search and get tools — avoids N+1 follow-up calls for common research workflows

Getting started

Public Hosted Instance

A public instance is available at https://openstates.caseyjhand.com/mcp — no installation required. Point any MCP client at it via Streamable HTTP:

{
  "mcpServers": {
    "openstates-mcp-server": {
      "type": "streamable-http",
      "url": "https://openstates.caseyjhand.com/mcp"
    }
  }
}

Self-Hosted / Local

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 v1.4.0 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:

  shCopy

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

• Run checks and tests:

  shCopy

  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 are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.