CongressMCP Documentation

22 MCP tools for searching, analyzing, and understanding U.S. congressional data. Bills, members, votes, committees, and AI-powered enrichments.

Getting Started

1. Register for an API key

Create a free account at /register to get your API key. No credit card required. The free tier includes 100 requests per month.

2. Add to Claude Code

Run this command to register CongressMCP as an MCP server in Claude Code:

claude mcp add congressmcp \ --transport http \ https://congressmcp.com/mcp \ --header "Authorization: Bearer YOUR_KEY"

3. Add to Claude Desktop

Add the following to your Claude Desktop settings.json:

{ "mcpServers": { "congressmcp": { "type": "streamable-http", "url": "https://congressmcp.com/mcp", "headers": { "Authorization": "Bearer YOUR_KEY" } } } }

Replace YOUR_KEY with the API key you received during registration.

Authentication

All requests to the MCP endpoint require an Authorization header with a Bearer token:

Authorization: Bearer sk_live_...

API keys are prefixed with sk_live_. Keep your key secret and never share it publicly.

Rate Limits

Free tier: 100 requests/month, 10 requests/minute
Pro tier: 10,000 requests/month, 60 requests/minute

When you exceed your monthly limit, the API returns 429 Too Many Requests with an upgrade prompt. Rate limits reset on the first of each month.

Bills

Search, retrieve, and explore legislation from Congress.

search_bills

Search congressional bills by keyword, topic, or bill number. Returns matching bills with titles, sponsors, and status.

Parameter	Type	Required	Description
query	string	required	Search term (keyword, topic, or bill number)
congress	number	optional	Filter by congress number (e.g. 119)
limit	number	optional	Max results to return (default: 20, max: 50)
offset	number	optional	Pagination offset (default: 0)

Show example response

[
  {
    "congress": 119,
    "type": "hr",
    "number": 1234,
    "title": "Example Act of 2025",
    "sponsor_name": "John Smith",
    "sponsor_party": "D",
    "sponsor_state": "CA",
    "latest_action": "Referred to committee",
    "latest_action_date": "2025-03-15"
  }
]

get_bill

Get detailed information about a specific bill including sponsor, cosponsors count, subjects, and latest summary.

Parameter	Type	Required	Description
congress	number	required	Congress number (e.g. 119)
type	string	required	Bill type (e.g. "hr", "s", "hjres", "sjres")
number	number	required	Bill number

Show example response

{
  "congress": 119,
  "type": "hr",
  "number": 1234,
  "title": "Example Act of 2025",
  "introduced_date": "2025-01-10",
  "sponsor_bioguide_id": "S000123",
  "sponsor_name": "John Smith",
  "sponsor_party": "D",
  "cosponsor_count": 42,
  "latest_action": "Passed House",
  "latest_action_date": "2025-06-12",
  "policy_area": "Health",
  "subjects": ["Medicare", "Drug prices"]
}

get_bill_actions

Get the legislative timeline/actions for a bill.

Parameter	Type	Required	Description
congress	number	required	Congress number
type	string	required	Bill type
number	number	required	Bill number
limit	number	optional	Max actions to return (default: 25)

Show example response

[
  {
    "action_date": "2025-06-12",
    "action_text": "Passed/agreed to in House: On passage Passed by Yea-Nay Vote: 275 - 160.",
    "action_type": "Floor",
    "action_code": "H37300"
  },
  {
    "action_date": "2025-03-15",
    "action_text": "Referred to the Committee on Energy and Commerce.",
    "action_type": "IntroReferral",
    "action_code": "H11100"
  }
]

get_bill_cosponsors

Get the list of cosponsors for a bill with party affiliation.

Parameter	Type	Required	Description
congress	number	required	Congress number
type	string	required	Bill type
number	number	required	Bill number

Show example response

[
  {
    "bioguide_id": "J000123",
    "first_name": "Jane",
    "last_name": "Doe",
    "party": "R",
    "state": "TX",
    "cosponsor_date": "2025-02-01"
  }
]

get_bill_text

Get available text versions for a bill with download URLs.

Parameter	Type	Required	Description
congress	number	required	Congress number
type	string	required	Bill type
number	number	required	Bill number

Show example response

[
  {
    "date": "2025-03-15",
    "type": "Introduced in House",
    "url": "https://www.congress.gov/119/bills/hr1234/BILLS-119hr1234ih.xml",
    "formats": ["xml", "pdf", "htm"]
  }
]

Members

Search and retrieve information about members of Congress.

search_members

Search for members of Congress by name. Supports fuzzy matching.

Parameter	Type	Required	Description
query	string	required	Name to search for (supports fuzzy matching)
chamber	string	optional	"House" or "Senate"
party	string	optional	Party filter (e.g. "D", "R")
state	string	optional	State abbreviation (e.g. "CA")
current_only	boolean	optional	Only current members (default: true)
limit	number	optional	Max results (default: 20)

Show example response

[
  {
    "bioguide_id": "P000197",
    "first_name": "Nancy",
    "last_name": "Pelosi",
    "party": "D",
    "state": "CA",
    "district": 11,
    "chamber": "House",
    "current_member": true
  }
]

get_member

Get detailed information about a member of Congress including terms served, bills sponsored/cosponsored, and vote count.

Parameter	Type	Required	Description
bioguide_id	string	required	Bioguide identifier (e.g. "P000197")

Show example response

{
  "bioguide_id": "P000197",
  "first_name": "Nancy",
  "last_name": "Pelosi",
  "party": "D",
  "state": "CA",
  "chamber": "House",
  "terms_served": 19,
  "bills_sponsored": 312,
  "bills_cosponsored": 4521,
  "total_votes": 14892,
  "current_member": true
}

get_member_legislation

Get bills sponsored or cosponsored by a member.

Parameter	Type	Required	Description
bioguide_id	string	required	Bioguide identifier
type	string	required	"sponsored" or "cosponsored"
congress	number	optional	Filter by congress number
limit	number	optional	Max results (default: 25)

Show example response

[
  {
    "congress": 119,
    "type": "hr",
    "number": 456,
    "title": "Infrastructure Investment Act",
    "introduced_date": "2025-02-14",
    "latest_action": "Referred to committee"
  }
]

Votes

Access voting records and roll call data.

get_member_votes

Get voting record for a member of Congress. Returns their votes on recorded roll calls.

Parameter	Type	Required	Description
bioguide_id	string	required	Bioguide identifier
congress	number	optional	Congress number (default: 119)
limit	number	optional	Max results (default: 50, max: 100)
offset	number	optional	Pagination offset (default: 0)

Show example response

[
  {
    "vote_cast": "Yea",
    "question_text": "On Passage - H.R. 1234",
    "result": "Passed",
    "vote_date": "2025-06-12",
    "vote_congress": 119,
    "vote_chamber": "House",
    "vote_session": 1,
    "vote_roll_call": 287
  }
]

get_vote_detail

Get details of a specific recorded vote including party breakdown.

Parameter	Type	Required	Description
chamber	string	required	"House" or "Senate"
congress	number	required	Congress number
session	number	required	Session number (1 or 2)
roll_call	number	required	Roll call number

Show example response

{
  "congress": 119,
  "chamber": "House",
  "session_number": 1,
  "roll_call_number": 287,
  "question_text": "On Passage - H.R. 1234",
  "result": "Passed",
  "vote_date": "2025-06-12",
  "yea_total": 275,
  "nay_total": 160,
  "not_voting": 0,
  "democrat_yea": 200,
  "democrat_nay": 12,
  "republican_yea": 75,
  "republican_nay": 148
}

score_members_on_votes

Score all members on a set of votes. Provide vote IDs with your preferred position (yea/nay) to generate a scorecard.

Parameter	Type	Required	Description
yea_vote_ids	number[]	required	Roll call vote IDs where you prefer a Yea
nay_vote_ids	number[]	required	Roll call vote IDs where you prefer a Nay

Show example response

[
  {
    "bioguide_id": "S000123",
    "name": "John Smith",
    "party": "D",
    "state": "CA",
    "score": 0.92,
    "votes_counted": 12,
    "aligned_votes": 11
  }
]

Committees

Explore congressional committees and their membership.

get_committees

List congressional committees. Filter by chamber or congress.

Parameter	Type	Required	Description
chamber	string	optional	"House", "Senate", or "Joint"
congress	number	optional	Congress number (default: 119)
limit	number	optional	Max results (default: 50)

Show example response

[
  {
    "system_code": "SSFI",
    "congress": 119,
    "name": "Committee on Finance",
    "chamber": "Senate",
    "type_code": "Standing",
    "subcommittees": [
      { "code": "SSFI01", "name": "Subcommittee on Health Care" }
    ]
  }
]

get_committee_members

Get members of a specific committee.

Parameter	Type	Required	Description
committee_code	string	required	The system_code of the committee (e.g. "SSFI")
congress	number	optional	Congress number (default: 119)

Show example response

[
  {
    "bioguide_id": "W000123",
    "name": "Ron Wyden",
    "party": "D",
    "state": "OR",
    "rank": 1,
    "role": "Chair"
  }
]

Enrichments Pro

AI-generated insights layered on top of raw congressional data. These tools require a Pro tier subscription.

get_bill_enrichment Pro

Get AI-generated enrichment for a bill including topic classification, significance rating, impact assessment, and plain-language summary.

Parameter	Type	Required	Description
congress	number	required	Congress number
type	string	required	Bill type
number	number	required	Bill number

Show example response

{
  "bill_ref": "119-hr-1234",
  "primary_topic": "Healthcare",
  "secondary_topics": ["Medicare", "Prescription Drugs"],
  "significance": "major",
  "impact_summary": "Would cap insulin costs at $35/month for all insured Americans.",
  "plain_language_summary": "This bill limits how much insurance companies can charge patients for insulin...",
  "issue_tags": ["insulin price cap", "drug pricing", "medicare reform"]
}

get_legislator_profile Pro

Get AI-generated legislator impact profile including archetype, topic authority, and vote courage.

Parameter	Type	Required	Description
bioguide_id	string	required	Bioguide identifier
congress	number	optional	Congress number (default: 119)

Show example response

{
  "bioguide_id": "P000197",
  "congress": 119,
  "archetype": "Coalition Builder",
  "topic_authority": ["Trade", "Foreign Affairs", "Immigration"],
  "vote_courage_score": 0.78,
  "legislative_effectiveness": "high",
  "bipartisan_index": 0.45
}

search_by_topic Pro

Search bills by AI-classified topic. Returns enriched bills matching a policy topic.

Parameter	Type	Required	Description
topic	string	required	Policy topic to search (e.g. "healthcare", "climate")
significance	string	optional	"landmark", "major", "moderate", "minor", or "routine"
congress	number	optional	Filter by congress number
limit	number	optional	Max results (default: 20)

Show example response

[
  {
    "bill_ref": "119-hr-1234",
    "primary_topic": "Healthcare",
    "significance": "major",
    "impact_summary": "Would cap insulin costs at $35/month...",
    "api_bills": {
      "title": "Example Act of 2025",
      "congress": 119
    }
  }
]

search_by_issue_tag Pro

Search bills by specific issue tag (e.g., "student loan forgiveness", "border wall", "insulin price cap").

Parameter	Type	Required	Description
tag	string	required	Issue tag to search for
limit	number	optional	Max results (default: 20)

Show example response

[
  {
    "bill_ref": "119-hr-5678",
    "primary_topic": "Education",
    "issue_tags": ["student loan forgiveness", "higher education"],
    "significance": "major",
    "api_bills": {
      "title": "Student Debt Relief Act",
      "congress": 119,
      "type": "hr",
      "number": 5678
    }
  }
]

Analysis Pro

Advanced analytical tools for comparing members, scoring votes, and reviewing aggregate statistics. The first three tools below require a Pro tier subscription.

get_party_unity Pro

Calculate party unity score for a member -- how often they vote with their party.

Parameter	Type	Required	Description
bioguide_id	string	required	Bioguide identifier
congress	number	optional	Congress number (default: 119)

Show example response

{
  "bioguide_id": "P000197",
  "party": "D",
  "congress": 119,
  "total_party_votes": 245,
  "votes_with_party": 232,
  "unity_score": 0.947
}

compare_members Pro

Compare two members of Congress -- shared cosponsored bills and voting alignment.

Parameter	Type	Required	Description
member1_bioguide	string	required	First member's bioguide ID
member2_bioguide	string	required	Second member's bioguide ID
limit	number	optional	Max shared bills to return (default: 10)

Show example response

{
  "shared_cosponsored_bills": [
    {
      "congress": 119,
      "type": "s",
      "number": 100,
      "title": "Bipartisan Infrastructure Act"
    }
  ],
  "member1_party_unity": { "unity_score": 0.947 },
  "member2_party_unity": { "unity_score": 0.891 }
}

get_legislation_stats

Get aggregate legislation statistics for a congress -- bill counts by type and status.

Parameter	Type	Required	Description
congress	number	optional	Congress number (default: 119)

Show example response

{
  "congress": 119,
  "total_bills": 12450,
  "by_type": {
    "hr": 8200,
    "s": 3100,
    "hjres": 150,
    "sjres": 80
  },
  "by_status": {
    "introduced": 10200,
    "passed_one_chamber": 1500,
    "became_law": 120
  }
}

get_vote_stats

Get voting statistics for a congress -- total votes, breakdowns by chamber.

Parameter	Type	Required	Description
congress	number	optional	Congress number (default: 119)

Show example response

{
  "congress": 119,
  "total_votes": 1245,
  "house_votes": 820,
  "senate_votes": 425
}

get_data_freshness

Check data freshness across all domains -- shows when each data type was last updated.

Parameter	Type	Required	Description
No parameters required.

Show example response

{
  "bills": {
    "last_updated": "2025-06-12T14:30:00Z",
    "total_records": 285000
  },
  "members": {
    "last_updated": "2025-06-12T14:30:00Z",
    "total_records": 13200
  },
  "votes": {
    "last_updated": "2025-06-12T12:00:00Z",
    "total_records": 52000
  }
}

REST API

In addition to the MCP interface, CongressMCP exposes standard REST endpoints for account management and billing.

POST /auth/register

Create a new account and receive an API key. Send { "email": "...", "name": "..." } as JSON body.

POST /auth/key Auth Required

Regenerate your API key. The old key is immediately revoked. Returns a new key.

GET /usage Auth Required

Get your current usage statistics: tier, requests this month, monthly limit, and rate limits.

POST /billing/checkout Auth Required

Create a Stripe checkout session to upgrade to the Pro tier. Returns a checkout_url.

POST /billing/portal Auth Required

Create a Stripe customer portal session to manage your subscription. Returns a portal_url.

Rate Limits & Pricing

Feature	Free	Pro
Price	$0/month	$20/month
Monthly Requests	100	10,000
Rate Limit	10 req/min	60 req/min
Bills, Members, Votes, Committees	All tools	All tools
Enrichments (AI-generated insights)	--	All 4 tools
Analysis (party unity, compare members)	--	All 5 tools
Support	Community	Priority email

Limits reset on the 1st of each month at midnight UTC. If you exceed your monthly quota, the API returns HTTP 429. Upgrade anytime at /billing/checkout.