NebulaGraph MCP Server

Instructions

Implementation Reference

• src/nebulagraph_mcp_server/server.py:190-225 (handler)

  The 'execute_query' tool handler function. Decorated with @mcp.tool(), it connects to NebulaGraph, switches to the specified space, executes the provided query, formats and returns the results or error message.

  @mcp.tool()
  def execute_query(query: str, space: str) -> str:
      """Execute a query
      Args:
          query: The query to execute
          space: The space to use
      Returns:
          The results of the query
      """
      pool = get_connection_pool()
      session = pool.get_session(
          os.getenv("NEBULA_USER", "root"), os.getenv("NEBULA_PASSWORD", "nebula")
      )
  
      try:
          session.execute(f"USE {space}")
          result = session.execute(query)
          if result.is_succeeded():
              # Format the query results
              if result.row_size() > 0:
                  columns = result.keys()
                  output = "Results:\n"
                  output += " | ".join(columns) + "\n"
                  output += "-" * (len(" | ".join(columns))) + "\n"
  
                  # Iterate through all rows
                  for i in range(result.row_size()):
                      row = result.row_values(i)
                      output += " | ".join(str(val) for val in row) + "\n"
                  return output
              return "Query executed successfully (no results)"
          else:
              return f"Query failed: {result.error_msg()}"
      finally:
          session.release()

• src/nebulagraph_mcp_server/server.py:190-190 (registration)

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

  @mcp.tool()

• src/nebulagraph_mcp_server/server.py:191-198 (schema)

  Function signature and docstring define the input schema (query: str, space: str) and output (str) for the tool, used by MCP for validation.

  def execute_query(query: str, space: str) -> str:
      """Execute a query
      Args:
          query: The query to execute
          space: The space to use
      Returns:
          The results of the query
      """