MCP Variance Log

Instructions

Implementation Reference

• src/mcp_variance_log/server.py:371-375 (handler)

  Handler for the 'write_query' tool. Validates that the provided query is not a SELECT statement and executes it on the database using db._execute_query.

  if name == "write_query":
      if arguments["query"].strip().upper().startswith("SELECT"):
          raise ValueError("SELECT queries are not allowed for write_query")
      results = db._execute_query(arguments["query"])
      return [types.TextContent(type="text", text=str(results))]

• src/mcp_variance_log/server.py:184-197 (registration)

  Registration of the 'write_query' tool within the list_tools handler, defining its name, description, and JSON schema for input validation.

  types.Tool(
      name="write_query",
      description="Execute an INSERT, UPDATE, or DELETE query",
      inputSchema={
          "type": "object",
          "properties": {
              "query": {
                  "type": "string",
                  "description": "Non-SELECT SQL query to execute"
              }
          },
          "required": ["query"]
      }
  ),

• src/mcp_variance_log/server.py:187-196 (schema)

  JSON Schema definition for the 'write_query' tool input, specifying a required 'query' string parameter.

  inputSchema={
      "type": "object",
      "properties": {
          "query": {
              "type": "string",
              "description": "Non-SELECT SQL query to execute"
          }
      },
      "required": ["query"]
  }