Sign up for a free Congress.gov API key at https://api.congress.gov/sign-up/ and store it as the api_key query parameter
List recent bills in a congress: GET https://api.congress.gov/v3/bill/{congress}/{billType}?api_key={key}&limit=20&offset=0&sort=updateDate+desc — billType is hr, s, hjres, sjres, hconres, sconres, or hres
Retrieve the full bill detail including title, sponsors, committees, and latestAction: GET https://api.congress.gov/v3/bill/{congress}/{billType}/{billNumber}?api_key={key}
Fetch all legislative actions ordered chronologically: GET https://api.congress.gov/v3/bill/{congress}/{billType}/{billNumber}/actions?api_key={key}&limit=250
List cosponsors and their party, state, and sponsorship date: GET .../cosponsors?api_key={key}
Retrieve the full text versions and their URLs: GET .../text?api_key={key} — then follow the URL in each version to download the enrolled or engrossed bill text from Congress.gov or GovInfo
Known gotchas
The Congress.gov API has experienced multi-day outages in 2026 (api.congress.gov/v3 has entered redirect loops that prevent all access); build retry logic with exponential backoff and maintain a GovInfo BILLSTATUS bulk XML fallback for production-critical pipelines
The new API key signup system was also affected during the 2026 outages, meaning developers could not obtain new keys during the downtime — provision keys well in advance and store them securely
Bill text URLs in the /text endpoint point to the Library of Congress or GovInfo servers, not the API itself; these secondary requests are not covered by the Congress.gov API rate limit (5000 req/hour) and may have separate throttling
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp