Congress[.]gov MCP Server

Instructions

Implementation Reference

• server.py:28-97 (handler)

  The primary handler for the 'get_bills' tool. Decorated with @mcp.tool() for registration in FastMCP. Implements logic to query Congress.gov API for bills using provided parameters, handles URL construction, request parameters, and error handling.

  @mcp.tool()
  async def get_bills(
      congress: int | None = None,
      bill_type: str | None = None,
      bill_number: int | None = None,
      offset: int = 0,
      limit: int = 20,
      from_datetime: str | None = None,
      to_datetime: str | None = None,
      sort: str = "updateDate+desc"
  ) -> dict:
      """
      Retrieve a list of bills. Full documentation for this endpoint -> https://github.com/LibraryOfCongress/api.congress.gov/blob/main/Documentation/BillEndpoint.md
  
      Args:
          congress: Congress number (e.g., 118 for 118th Congress)
          bill_type: Type of bill
              - hr: House of Representatives Bill
              - s: Senate Bill
              - hjres: House Joint Resolution
              - sjres: Senate Joint Resolution
              - hconres: House Concurrent Resolution
              - sconres: Senate Concurrent Resolution
              - hres: House Simple Resolution
              - sres: Senate Simple Resolution
          bill_number: Specific bill number (requires congress and bill_type)
          offset: Starting record (default 0)
          limit: Maximum records to return (max 250, default 20)
          from_datetime: Start timestamp (YYYY-MM-DDTHH:MM:SSZ format)
          to_datetime: End timestamp (YYYY-MM-DDTHH:MM:SSZ format)
          sort: Sort order ('updateDate+asc' or 'updateDate+desc')
  
      Returns:
          dict: Bill data from Congress.gov API
      """
      base_url = "https://api.congress.gov/v3/bill"
  
      url = base_url
      if congress:
          url += f"/{congress}"
          if bill_type:
              url += f"/{bill_type}"
              if bill_number:
                  url += f"/{bill_number}"
  
      params = {
          "api_key": congress_gov_api_key,
          "format": "json",
          "offset": offset,
          "limit": min(limit, 100)  # Enforce API max limit
      }
  
      if from_datetime:
          params["fromDateTime"] = from_datetime
      if to_datetime:
          params["toDateTime"] = to_datetime
      if not bill_number:
          params["sort"] = sort
  
      try:
          response = requests.get(url, params=params)
          response.raise_for_status()
          return response.json()
  
      except requests.exceptions.RequestException as e:
          return {
              "error": f"Failed to retrieve bills: {str(e)}",
              "status_code": getattr(e.response, "status_code", None)
          }

• server.py:28-28 (registration)

  The @mcp.tool() decorator registers the get_bills function as an MCP tool.

  @mcp.tool()

• server.py:29-62 (schema)

  Function signature with type annotations and comprehensive docstring defining input parameters and output for the get_bills tool schema.

  async def get_bills(
      congress: int | None = None,
      bill_type: str | None = None,
      bill_number: int | None = None,
      offset: int = 0,
      limit: int = 20,
      from_datetime: str | None = None,
      to_datetime: str | None = None,
      sort: str = "updateDate+desc"
  ) -> dict:
      """
      Retrieve a list of bills. Full documentation for this endpoint -> https://github.com/LibraryOfCongress/api.congress.gov/blob/main/Documentation/BillEndpoint.md
  
      Args:
          congress: Congress number (e.g., 118 for 118th Congress)
          bill_type: Type of bill
              - hr: House of Representatives Bill
              - s: Senate Bill
              - hjres: House Joint Resolution
              - sjres: Senate Joint Resolution
              - hconres: House Concurrent Resolution
              - sconres: Senate Concurrent Resolution
              - hres: House Simple Resolution
              - sres: Senate Simple Resolution
          bill_number: Specific bill number (requires congress and bill_type)
          offset: Starting record (default 0)
          limit: Maximum records to return (max 250, default 20)
          from_datetime: Start timestamp (YYYY-MM-DDTHH:MM:SSZ format)
          to_datetime: End timestamp (YYYY-MM-DDTHH:MM:SSZ format)
          sort: Sort order ('updateDate+asc' or 'updateDate+desc')
  
      Returns:
          dict: Bill data from Congress.gov API
      """