NIX MCP Server

Instructions

Implementation Reference

• src/nix_mcp/server_fastmcp.py:89-100 (handler)

  MCP tool registration, input schema, and handler for the 'query' tool. Validates parameters and executes via handle_query.

  @mcp.tool()
  async def query(
      action: str = Field(..., description="Query action name"),
      params: Optional[Dict[str, Any]] = Field(default=None, description="JSON parameters for the query"),
      contract: str = Field(default="nix.q", description="Contract name"),
      environment: str = Field(default="dev", description="Environment (dev, uat, cdev, perf, simnext, prod, local)")
  ) -> str:
      """Execute a NIX query with JSON parameters"""
      # Create client with specified environment
      client = SimpleNixClient(environment=environment)
      result = await handle_query(client, action, params, contract, environment)
      return result[0].text

• src/nix_mcp/tools.py:116-163 (helper)

  Core helper function implementing the query execution logic using SimpleNixClient.query(), handling JSON/text responses and errors.

  async def handle_query(
      client: SimpleNixClient,
      action: str,
      params: Optional[Dict[str, Any]] = None,
      contract: str = "nix.q",
      environment: str = "dev"
  ) -> List[TextContent]:
      """
      Execute a NIX query with JSON parameters
      
      Args:
          client: SimpleNixClient instance
          action: Query action name
          params: JSON parameters for the query
          contract: Contract name (default: nix.q)
          environment: Environment name
      
      Returns:
          List containing TextContent with query result
      """
      try:
          # Execute the query
          result = await client.query(
              contract=contract,
              action=action,
              params=params or {}
          )
          
          # Handle both JSON and raw text responses
          if isinstance(result, dict):
              # Add environment info to result if it's a dict
              result["environment"] = environment
              return [TextContent(
                  type="text",
                  text=json.dumps(result, indent=2)
              )]
          else:
              # Return raw text response
              return [TextContent(
                  type="text",
                  text=str(result)
              )]
      except Exception as e:
          logger.error(f"Error executing query: {e}")
          return [TextContent(
              type="text",
              text=f"Error: {str(e)}"
          )]