congressgov-mcp-server

Public Hosted Server: https://congressgov.caseyjhand.com/mcp

Overview

US congressional data from Congress.gov and the Senate's official vote feed: bills, enacted laws, members, committees, roll call votes, nominations, CRS and committee reports, and the Congressional Record. Browse legislative activity, read bill and report text, and follow nominations through Senate confirmation.

Tools

Resources

Bill, member, and committee data is also reachable through congressgov_bill_lookup, congressgov_member_lookup, and congressgov_committee_lookup (operation get), since many MCP clients are tool-only and never surface resources.

Prompts

Agent skill

congressgov-guide guides research across bills, laws, members, committees, votes, and floor debate. It covers identifier provenance, discovery limits, and version-specific document evidence. The guide ships with plugin installs, npm, MCPB, and Docker, and is served over MCP through the Skills extension and its skill:// resource.

Related MCP server: Congress.gov API MCP Server

Capability reference

congressgov_bill_lookup tool

• list browses one congress, narrowed by billType and a fromDateTime/toDateTime range on the record's update date, newest first unless order: 'oldest'; get, actions, amendments, cosponsors, committees, subjects, summaries, text, titles, related, and content need congress + billType + billNumber

• type and number from a bill row are accepted as billType and billNumber; bill type codes are case-insensitive. Send one name per field, since canonical and alias keys together are rejected

• content reads the text version at textVersionIndex (0 is the most recent) and returns one character window in content.text with totalCharacters, truncated, and nextOffset

• summaries takes an optional versionCode (00 introduced, 49 public law) and pages like congressgov_bill_summaries, using characterOffset/characterLimit

congressgov_enacted_laws tool

• list browses one congress, optionally by lawType (pub or priv), the enactment filter congressgov_bill_lookup lacks; get needs lawType + lawNumber, taken from a list row's laws[].number (118-90) or its bare number (90)

• get returns the origin bill record, with the law citation on its laws[] array

congressgov_member_lookup tool

• No name search: list filters by stateCode (plus district, 0 for at-large, which requires stateCode), congress, and currentMember

• get returns the profile for a bioguideId (e.g. P000197); sponsored and cosponsored return that member's legislation

congressgov_committee_lookup tool

• committeeCode is a chamber prefix (h/s/j), letters, and a 2-digit suffix (e.g. hsju00); get, bills, reports, and the Senate-only nominations infer chamber from the prefix

• A committee name in committeeCode resolves when exactly one committee matches, and otherwise returns candidate rows with a notice; list with filter name-matches every committee in scope, and fuzzy hits carry approximate: true

• bills is newest first by default (order), and its rows carry no titles, so chain congressgov_bill_lookup get per row

congressgov_roll_votes tool

• chamber is house (default, Congress.gov API) or senate (the Senate's LIS feed); every call needs congress + session (1 or 2), and get/members add voteNumber, which resets each session and is specific to one chamber

• list is newest first unless order: 'oldest'; get returns the question, result, tallies, and party breakdown, and members returns each member's position

• Senate votes start at the 101st Congress (1989), and Senate rows pair the feed's year-less voteDate with a derived voteDateIso

congressgov_senate_nominations tool

• list browses one congress; get, actions, committees, hearings, and nominees need a nominationNumber (1000 for PN1000), and nominees also needs an ordinal from the nominees array get returns

• Multi-part nominations (e.g. PN851) keep their activity on partitioned children (851-1, 851-2, …); an empty sub-resource call on the bare number returns a notice pointing there

congressgov_bill_summaries tool

• Optional congress and billType (which requires congress); fromDateTime/toDateTime filter on the summary's update time, not the bill's action date, and cover the last 7 days when both are omitted

• A page stops adding rows at 50,000 serialized characters (at least one row always returns, and pagination.nextOffset resumes); a summary over 25,000 characters arrives windowed with textTotalCharacters, textTruncated, and textNextOffset

• For one bill's summaries, or to read a windowed summary to the end, use congressgov_bill_lookup summaries

congressgov_crs_reports tool

• list browses the catalog; get takes a reportNumber such as R40097, RL33612, or IF12345

• id, reportId, and report_id are accepted as reportNumber; send only one identifier key

• get returns authors, topics, summary, and download formats

congressgov_committee_reports tool

• list browses one congress, optionally by reportType (hrpt House, srpt Senate, erpt Executive); get, text, and content need reportType + reportNumber

• get returns the citation, title, committees, and associated bill; text lists {type, url} format links, and content reads the report as one character window

congressgov_daily_record tool

• Navigation runs list (volumes) → issues (by volumeNumber) → articles (by volumeNumber + issueNumber)

• content reads the article at articleIndex (0-based across the issue) as one character window; Record articles publish Formatted Text and PDF only, so format: 'xml' fails as format_unavailable

congressgov_search_bills tool

• query keywords (AND-combined) over bill titles and CRS summaries, narrowed by congress, billType, and originChamber; limit 1–100, offset pagination

• BM25-ranked rows carry billId plus congress/billType/billNumber for congressgov_bill_lookup, and a summaryPreview; policy area and full bill text are not indexed

• Listed only when CONGRESS_MIRROR_ENABLED=true; until bun run mirror:init builds the index, it returns an empty result with a notice

congress://current resource

• Current congress number, session dates, and chamber info, the baseline for other queries

• Cached publicly for 1 hour

congress://bill-types resource

• The 8 bill type codes (hr, s, hjres, sjres, hconres, sconres, hres, sres) with description, chamber, and an example citation

• Static, with no upstream call; cached publicly for 24 hours

congress://member/{bioguideId} resource

• bioguideId is one uppercase letter and 6 digits (e.g. P000197)

• Returns the member profile: name, state, party, terms, leadership, office, legislation counts

congress://bill/{congress}/{billType}/{billNumber} resource

• congress and billNumber are positive integers; billType is one of the 8 bill type codes

• Returns bill detail: sponsor, status, policy area, committees, latest action

congress://committee/{committeeCode} resource

• committeeCode is h/s/j followed by 3–8 lowercase alphanumeric characters (e.g. hsju00); chamber comes from the first letter

• Returns committee detail: name, chamber, subcommittees, history, legislation counts

congressgov_bill_analysis prompt

• Arguments: congress, billType, and billNumber, all required

• Returns one user message framing a seven-part analysis, from summary to outlook, with the tools to call for each part

congressgov_legislative_research prompt

• Arguments: topic required; congress optional, defaulting to the current congress

• With CONGRESS_MIRROR_ENABLED, the plan opens with congressgov_search_bills; without it, the prompt asks for a seed bill, member, committee, or CRS report ID, since no other tool takes a topic

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.

Congress.gov-specific:

• Type-safe client for the Congress.gov REST API v3, plus a client for the Senate's LIS XML feed that backs Senate roll votes

• The Congress.gov API has no keyword search, so tools browse by congress, type, date range, chamber, state, and district; list operations page with limit 1–250 (default 20) and offset

• content on bill text, committee reports, and Record articles reads format text (default) or xml in a characterOffset/characterLimit window (1–100,000 characters, default 25,000), fetched only from www.congress.gov under a 25 MB ceiling and a 30s deadline

• Optional API key from api.data.gov: DEMO_KEY allows 30 requests/hour and 50/day per IP, registered keys 5,000/hour

• Opt-in local SQLite FTS5 mirror (CONGRESS_MIRROR_ENABLED) adds keyword search over bill titles and CRS summaries

Agent-friendly output:

• Every list response carries effectiveQuery and totalCount, with a notice when nothing matched

• list rejects detail-only identifiers (billNumber, voteNumber, nominationNumber, reportNumber, volumeNumber) with an incompatible_identity error that names the operation to use instead

• content returns offset, truncated, and nextOffset, so walking a multi-megabyte bill never skips or repeats a character

• Typed failures (document_unavailable, format_unavailable, document_fetch_failed, document_too_large, offset_past_end, not_found, rate_limited, invalid_request, upstream_error, upstream_timeout), each with a recovery hint

Getting started

Connect to the hosted instance:

claude mcp add --transport http congressgov-mcp-server https://congressgov.caseyjhand.com/mcp

Or run it locally:

claude mcp add congressgov-mcp-server -- npx -y @cyanheads/congressgov-mcp-server

For other clients, add this to the MCP config file:

{
  "mcpServers": {
    "congressgov-mcp-server": {
      "command": "npx",
      "args": ["-y", "@cyanheads/congressgov-mcp-server"]
    }
  }
}

Optional: set CONGRESS_API_KEY to a free api.data.gov key for 5,000 requests/hour instead of the demo key's 30/hour and 50/day per IP. For Docker or a source build, see Running the server.

Configuration

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

Running the server

Requires Bun v1.4.0 or higher (or Node.js v24+).

git clone https://github.com/cyanheads/congressgov-mcp-server.git
cd congressgov-mcp-server && bun install
cp .env.example .env
# Optionally set CONGRESS_API_KEY and the mirror variables in .env.

Local development

• Build and run the production version:

  bun run rebuild
  bun run start:http   # or start:stdio

• Build the bill search mirror from this checkout (with CONGRESS_MIRROR_ENABLED=true):

  bun run mirror:init      # full build
  bun run mirror:refresh   # incremental refresh
  bun run mirror:verify    # readiness and integrity check

  The mirror CLI requires this checkout or the Docker image's path mapping; an npm installation cannot run these scripts.

• 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 run --rm -e CONGRESS_API_KEY=your-api-key -p 3010:3010 ghcr.io/cyanheads/congressgov-mcp-server:latest

The image defaults to HTTP transport, stateless session mode, and logs to /var/log/congressgov-mcp-server. For stdio, use docker run -i --rm -e MCP_TRANSPORT_TYPE=stdio ghcr.io/cyanheads/congressgov-mcp-server:latest. To build locally, run docker build -t congressgov-mcp-server .; OpenTelemetry peer dependencies are installed by default, with --build-arg OTEL_ENABLED=false to omit them. The image carries the mirror scripts, so docker exec <container> bun run mirror:init builds the index in place.

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

• All tools are read-only, with readOnlyHint: true and idempotentHint: true annotations

• Wrap external API calls: validate raw → normalize to a domain type → return the 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.