Snowflake MCP Server

Instructions

Implementation Reference

• src/mcp_snowflake_server/server.py:137-180 (handler)

  The handler function that implements the list_tables tool logic: validates input, constructs SQL query to list tables from information_schema.tables in the given database.schema, applies table exclusion filters, formats output as YAML text and JSON embedded resource.

  async def handle_list_tables(arguments, db, *_, exclusion_config=None):
      if not arguments or "database" not in arguments or "schema" not in arguments:
          raise ValueError("Missing required 'database' and 'schema' parameters")
  
      database = arguments["database"]
      schema = arguments["schema"]
  
      query = f"""
          SELECT table_catalog, table_schema, table_name, comment 
          FROM {database}.information_schema.tables 
          WHERE table_schema = '{schema.upper()}'
      """
      data, data_id = await db.execute_query(query)
  
      # Filter out excluded tables
      if exclusion_config and "tables" in exclusion_config and exclusion_config["tables"]:
          filtered_data = []
          for item in data:
              table_name = item.get("TABLE_NAME", "")
              exclude = False
              for pattern in exclusion_config["tables"]:
                  if pattern.lower() in table_name.lower():
                      exclude = True
                      break
              if not exclude:
                  filtered_data.append(item)
          data = filtered_data
  
      output = {
          "type": "data",
          "data_id": data_id,
          "database": database,
          "schema": schema,
          "data": data,
      }
      yaml_output = data_to_yaml(output)
      json_output = json.dumps(output)
      return [
          types.TextContent(type="text", text=yaml_output),
          types.EmbeddedResource(
              type="resource",
              resource=types.TextResourceContents(uri=f"data://{data_id}", text=json_output, mimeType="application/json"),
          ),
      ]

• src/mcp_snowflake_server/server.py:455-461 (schema)

  Input schema definition for list_tables tool specifying required 'database' and 'schema' string parameters.

      "type": "object",
      "properties": {
          "database": {"type": "string", "description": "Database name"},
          "schema": {"type": "string", "description": "Schema name"},
      },
      "required": ["database", "schema"],
  },

• src/mcp_snowflake_server/server.py:451-463 (registration)

  Tool registration object creation for list_tables, including name, description, input schema, and reference to the handler function. Added to the all_tools list used by list_tools and call_tool handlers.

  Tool(
      name="list_tables",
      description="List all tables in a specific database and schema",
      input_schema={
          "type": "object",
          "properties": {
              "database": {"type": "string", "description": "Database name"},
              "schema": {"type": "string", "description": "Schema name"},
          },
          "required": ["database", "schema"],
      },
      handler=handle_list_tables,
  ),