congressgov-mcp-server

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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

Tool	Description
congressgov_bill_lookup	Browse and retrieve bills: actions, sponsors, summaries, text, related bills
congressgov_enacted_laws	Browse enacted public and private laws by congress
congressgov_member_lookup	Find members by state, district, or congress, and retrieve their legislative portfolios
congressgov_committee_lookup	Browse committees and their legislation, reports, and nominations
congressgov_roll_votes	Retrieve House and Senate roll call votes and each member's position
congressgov_senate_nominations	Browse presidential nominations and track Senate confirmation
congressgov_bill_summaries	Browse recently updated CRS bill summaries
congressgov_crs_reports	Browse and retrieve nonpartisan CRS policy reports
congressgov_committee_reports	Browse and read committee reports accompanying legislation
congressgov_daily_record	Browse and read the daily Congressional Record
congressgov_search_bills	Keyword-search bill titles and CRS summaries via a local full-text mirror (opt-in)

Resources

Resource	Description
congress://current	Current congress number, session dates, chamber info
congress://bill-types	Reference table of valid bill type codes
congress://member/{bioguideId}	Member profile by bioguide ID
congress://bill/{congress}/{billType}/{billNumber}	Bill detail by congress, type, and number
congress://committee/{committeeCode}	Committee detail by committee code

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

Prompt	Description
congressgov_bill_analysis	Structured framework for analyzing a bill
congressgov_legislative_research	Research framework for a policy area across Congress

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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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congress://current _resource

• Current congress number, session dates, and chamber info, the baseline for other queries
• Cached publicly for 1 hour

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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

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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

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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

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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

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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

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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

Public Hosted Instance

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

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

Self-Hosted / Local

Add the following to your MCP client configuration file.

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

Or with npx (no Bun required):

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

Or with Docker:

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

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

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

Prerequisites

• Bun v1.4.0 or higher (or Node.js v24+).
• Optional: a free api.data.gov key raises the limit to 5,000 requests/hour from the demo key's 30/hour and 50/day per IP.

Installation

1. Clone the repository:

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

2. Navigate into the directory:

cd congressgov-mcp-server

3. Install dependencies:

bun install

4. Configure environment:

cp .env.example .env
# edit .env and set CONGRESS_API_KEY (and the mirror vars, if you want keyword search)

Configuration

Variable	Description	Default
CONGRESS_API_KEY	API key from api.data.gov.	DEMO_KEY
CONGRESS_API_BASE_URL	Congress.gov API base URL.	https://api.congress.gov/v3
CONGRESS_MIRROR_ENABLED	Enable the local bill search mirror and the congressgov_search_bills tool.	false
CONGRESS_MIRROR_PATH	Filesystem path to the SQLite mirror index.	.mirror/bills.sqlite3
CONGRESS_MIRROR_REFRESH_CRON	Cron schedule for the in-process mirror refresh (HTTP transport only). Unset means running mirror:refresh yourself.	—
CONGRESS_MIRROR_CONGRESSES	Comma-separated congress numbers to mirror (e.g. 118,119).	current congress + 1 prior
MCP_TRANSPORT_TYPE	Transport: stdio or http.	stdio
MCP_HTTP_PORT	HTTP server port.	3010
MCP_SESSION_MODE	HTTP session mode: stateless, stateful, or auto; auto resolves to stateful.	stateless
MCP_AUTH_MODE	Authentication: none, jwt, or oauth.	none
MCP_LOG_LEVEL	Log level (debug, info, notice, warning, error, etc.).	info
LOGS_DIR	Directory for log files (Node.js only).	<project-root>/logs
OTEL_ENABLED	Enable OpenTelemetry.	false
OTEL_EXPORTER_OTLP_ENDPOINT	Base OTLP endpoint for traces and metrics.	—
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT	Explicit OTLP logs endpoint; the base endpoint does not enable log export.	—
LOG_TOOL_FAILURE_PAYLOADS	Log failed-call input and output with key-based redaction; secrets inside free-form values are not redacted.	false
LOG_TOOL_FAILURE_PAYLOAD_MAX_BYTES	Maximum bytes per failed-call input or output record.	16384

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

Running the server

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 build -t congressgov-mcp-server .
docker run --rm -e CONGRESS_API_KEY=your-api-key -p 3010:3010 congressgov-mcp-server

The Dockerfile defaults to HTTP transport, stateless session mode, and logs to /var/log/congressgov-mcp-server. OpenTelemetry peer dependencies are installed by default; build 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

Directory	Purpose
src/index.ts	createApp() entry point: registers tools, resources, and prompts, inits services, and schedules the mirror refresh.
src/config/	Server-specific environment variable parsing and validation with Zod.
src/mcp-server/tools/	Tool definitions (definitions/*.tool.ts) plus shared input, formatting, and summary-window helpers.
src/mcp-server/resources/definitions/	Resource definitions (*.resource.ts).
src/mcp-server/prompts/definitions/	Prompt definitions (*.prompt.ts).
src/services/congress-api/	Congress.gov API client: auth, pagination, rate limiting.
src/services/congress-documents/	Bounded document-text fetch: host allowlist, byte ceiling, character window.
src/services/congress-mirror/	Local SQLite FTS5 bill-search mirror: ingest, normalize, schema.
src/services/senate-lis/	Senate LIS XML client for Senate roll call votes.
src/utils/	HTML/XML character-reference decoding.
scripts/	Build, devcheck, and release tooling, plus the mirror:init / mirror:refresh / mirror:verify CLIs.
tests/	Unit and integration tests, mirroring the src/ 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.