openstates-mcp-server

---

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

Tool	Description
openstates_search_bills	Search state legislative bills across all covered US jurisdictions with full-text search, jurisdiction/session filtering, subject tags, and sponsor lookups
openstates_get_bill	Fetch full detail for a specific bill by OCD ID or three-part path (jurisdiction + session + bill_id)
openstates_search_people	Search state legislators and officials within a jurisdiction by name, chamber, or district, or fetch specific people by OCD person ID
openstates_get_legislators_by_location	Find every legislator representing a geographic coordinate (latitude/longitude) — state legislators and the federal delegation
openstates_search_committees	List committees for a jurisdiction (experimental — not all states have coverage)
openstates_get_committee	Fetch committee detail by OCD organization ID, with optional membership roster
openstates_search_events	Search hearings, floor sessions, and committee meetings (experimental)
openstates_get_event	Fetch full event detail including agenda, participants, and media links
openstates_list_jurisdictions	List all 56 jurisdictions (50 states, DC, and 5 US territories) covered by Open States with session identifiers and coverage metadata
openstates_get_jurisdiction	Fetch full metadata for a specific jurisdiction including all legislative sessions and their identifiers

Resources

Resource	Description
openstates://jurisdiction/{jurisdiction_id}	Jurisdiction metadata including current sessions, coverage dates, and bill/people update timestamps

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

Prompt	Description
openstates_bill_research	Structured framework for analyzing a state bill: summary, sponsors, committee referrals, action timeline, vote record, and related legislation
openstates_legislator_profile	Research framework for profiling a legislator: sponsored bills, committee assignments, voting record, and contact details

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, from search results) or the three-part path jurisdiction + session + bill_id; a call missing both fails with missing_lookup_params
• 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 the ID or 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 (both chambers merged, 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; 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 result may mean no coverage, not no events
• 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 an OCD-ID, state name, or two-letter abbreviation
• 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

---

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 bill and committee fetchers (OCD ID or structured path)
• 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

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:

Variable	Description	Default
OPENSTATES_API_KEY	Required. Open States API key from open.pluralpolicy.com.	—
OPENSTATES_API_BASE_URL	Open States API base URL.	https://v3.openstates.org
OPENSTATES_DAILY_REQUEST_BUDGET	Maximum upstream requests per rolling 24 hours. Once spent, calls are rejected before the request is issued, so an over-budget call costs nothing upstream. The default matches the v3 free-tier daily cap — raise it if your key's tier allows more.	250
OPENSTATES_REQUEST_TIMEOUT_MS	Per-attempt upstream deadline in milliseconds (minimum 1000). Expiry is non-retryable, so a request that cannot complete costs one wait rather than four. Open States answers a scoped query anywhere from under a second to ~57s and its own gateway gives up near 60s — lower this to fail sooner, raise it to wait out a slow query.	45000
OPENSTATES_TOTAL_REQUEST_BUDGET_MS	Wall-clock ceiling in milliseconds for one call across every retry attempt and the backoff between them. The per-attempt deadline bounds a single request; this bounds the whole ladder, so a slow upstream that keeps failing retryably cannot hold a call open for the full retry sequence. Must be at least OPENSTATES_REQUEST_TIMEOUT_MS — startup rejects anything lower, which would abort every attempt before its own deadline applied. At the default of twice the deadline, an attempt that fails just short of its deadline still leaves a retry nearly a full deadline of its own.	90000
MCP_TRANSPORT_TYPE	Transport: stdio or http.	stdio
MCP_SESSION_MODE	HTTP session mode: auto, stateful, or stateless. src/index.ts declares stateless via createApp({ sessionMode }) — no tool suspends for caller input, so no session state is needed. Setting this overrides the declaration; the framework schema default is auto, which resolves to stateful.	stateless
MCP_HTTP_PORT	HTTP server port.	3010
MCP_HTTP_ENDPOINT_PATH	HTTP endpoint path.	/mcp
MCP_PUBLIC_URL	Public origin override for TLS-terminating reverse-proxy deployments.	none
MCP_AUTH_MODE	Auth mode: none, jwt, or oauth.	none
MCP_LOG_LEVEL	Log level (debug, info, notice, warning, error).	info
MCP_GC_PRESSURE_INTERVAL_MS	Opt-in Bun-only forced-GC interval (ms). Try 60000 if heap grows under sustained HTTP load.	0 (disabled)
LOGS_DIR	Directory for log files (Node.js only).	<project-root>/logs
STORAGE_PROVIDER_TYPE	Storage backend: in-memory, filesystem, supabase, cloudflare-kv/r2/d1.	in-memory
OTEL_ENABLED	Enable OpenTelemetry instrumentation.	false
OTEL_EXPORTER_OTLP_ENDPOINT	OTLP base URL; traces go to /v1/traces and metrics to /v1/metrics.	none
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT	Opt-in OTLP log export (e.g. http://localhost:4318/v1/logs); the base endpoint never enables it.	none
LOG_TOOL_FAILURE_PAYLOADS	Log each failed tool call's arguments and result, redacted by key name only, capped by LOG_TOOL_FAILURE_PAYLOAD_MAX_BYTES (default 16384).	false

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

Running the server

Local development

• Build and run the production version:

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

• Run checks and tests:

  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

Directory	Purpose
src/index.ts	createApp() entry point — registers tools, resources, prompts, and inits the Open States service.
src/config	Server-specific environment variable parsing and validation with Zod.
src/mcp-server/tools	Tool definitions (*.tool.ts). Ten tools across bills, people, committees, events, and jurisdictions.
src/mcp-server/resources	Resource definitions. Jurisdiction metadata resource.
src/mcp-server/prompts	Prompt definitions. Bill research and legislator profile prompts.
src/services/openstates	Open States API v3 service layer — HTTP client, request handling, domain types.
tests/	Unit and integration tests mirroring src/.

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.