NIX MCP Server

Instructions

Implementation Reference

• src/nix_mcp/server_fastmcp.py:62-72 (handler)

  Primary MCP tool handler for 'list_queries'. Decorated with @mcp.tool(), defines input schema via Pydantic Field, creates SimpleNixClient, calls helper function, and returns result as string.

  @mcp.tool()
  async def list_queries(
      contract: str = Field(default="nix.q", description="Contract to list queries from"),
      filter_pattern: Optional[str] = Field(default=None, description="Optional filter pattern for query names"),
      environment: str = Field(default="dev", description="Environment (dev, uat, cdev, perf, simnext, prod, local)")
  ) -> str:
      """List all available NIX query actions from the contract ABI"""
      # Create client with specified environment
      client = SimpleNixClient(environment=environment)
      result = await handle_list_queries(client, contract, filter_pattern, environment)
      return result[0].text

• src/nix_mcp/tools.py:15-58 (helper)

  Core helper function implementing the query listing logic: fetches actions using ABIFetcher, filters by pattern, formats as JSON TextContent, handles errors.

  async def handle_list_queries(
      client: SimpleNixClient,
      contract: str = "nix.q",
      filter_pattern: Optional[str] = None,
      environment: str = "dev"
  ) -> List[TextContent]:
      """
      List all available NIX query actions
      
      Args:
          client: SimpleNixClient instance
          contract: Contract to list queries from (default: nix.q)
          filter_pattern: Optional filter pattern for query names
          environment: Environment name
      
      Returns:
          List containing TextContent with available queries
      """
      try:
          fetcher = ABIFetcher(nodeos_api=client.nodeos_api, environment=environment)
          actions = fetcher.get_actions(contract)
  
          # Apply filter if provided
          if filter_pattern:
              filter_lower = filter_pattern.lower()
              actions = [a for a in actions if filter_lower in a.lower()]
          
          result = {
              "contract": contract,
              "environment": environment,
              "total_queries": len(actions),
              "queries": actions
          }
          
          return [TextContent(
              type="text",
              text=json.dumps(result, indent=2)
          )]
      except Exception as e:
          logger.error(f"Error listing queries: {e}")
          return [TextContent(
              type="text",
              text=f"Error: {str(e)}"
          )]

• src/nix_mcp/server_fastmcp.py:63-67 (schema)

  Input schema definition using Pydantic Field for the list_queries tool parameters.

  async def list_queries(
      contract: str = Field(default="nix.q", description="Contract to list queries from"),
      filter_pattern: Optional[str] = Field(default=None, description="Optional filter pattern for query names"),
      environment: str = Field(default="dev", description="Environment (dev, uat, cdev, perf, simnext, prod, local)")
  ) -> str:

• src/nix_mcp/server_fastmcp.py:13-17 (registration)

  Import of the handle_list_queries helper function used by the tool.

  from .tools import (
      handle_list_queries,
      handle_get_query_abi, 
      handle_query
  )