CockroachDB MCP Server

Instructions

Args:
    table: Table name (schema.table or just table).
    data: Column names and values to insert.
    returning: Columns to return from inserted row.

Returns:
    Insert result.

Implementation Reference

• src/cockroachdb_mcp/server.py:256-275 (handler)

  MCP tool handler for 'insert_row': registered with @mcp.tool() decorator, defines input schema via type hints and docstring, delegates execution to crud.insert_row with error handling.

  @mcp.tool()
  async def insert_row(
      table: str,
      data: dict[str, Any],
      returning: list[str] | None = None,
  ) -> dict[str, Any]:
      """Insert a new row into a table.
  
      Args:
          table: Table name (schema.table or just table).
          data: Column names and values to insert.
          returning: Columns to return from inserted row.
  
      Returns:
          Insert result.
      """
      try:
          return await crud.insert_row(table, data, returning)
      except Exception as e:
          return {"status": "error", "error": str(e)}

• src/cockroachdb_mcp/tools/crud.py:127-199 (helper)

  Core helper function implementing the insert_row logic: input validation, dynamic SQL INSERT query construction with optional RETURNING, database execution, and result formatting.

  async def insert_row(
      table: str,
      data: dict[str, Any],
      returning: list[str] | None = None,
  ) -> dict[str, Any]:
      """Insert a new row into a table.
  
      Args:
          table: Table name (schema.table or just table).
          data: Column names and values to insert.
          returning: Columns to return from inserted row.
  
      Returns:
          Insert result.
      """
      # Check read-only mode
      if settings.read_only:
          return {"status": "error", "error": "Server is in read-only mode"}
  
      # Validate table name
      valid, error = _validate_table_name(table)
      if not valid:
          return {"status": "error", "error": error}
  
      if not data:
          return {"status": "error", "error": "No data provided"}
  
      schema, table_name = _parse_table_name(table)
  
      # Validate column names
      for col in data.keys():
          if not re.match(r"^[\w]+$", col):
              return {"status": "error", "error": f"Invalid column name: {col}"}
  
      # Build INSERT query
      columns = list(data.keys())
      placeholders = ", ".join(["%s"] * len(columns))
      col_list = ", ".join(columns)
      values = list(data.values())
  
      query = f"INSERT INTO {schema}.{table_name} ({col_list}) VALUES ({placeholders})"
  
      # Add RETURNING clause
      if returning:
          for col in returning:
              if not re.match(r"^[\w]+$", col):
                  return {"status": "error", "error": f"Invalid column name in returning: {col}"}
          query += f" RETURNING {', '.join(returning)}"
  
      conn = await connection_manager.ensure_connected()
  
      try:
          async with conn.cursor() as cur:
              await cur.execute(query, tuple(values))
  
              if returning:
                  row = await cur.fetchone()
                  return {
                      "status": "success",
                      "table": f"{schema}.{table_name}",
                      "action": "inserted",
                      "returning": row,
                  }
              else:
                  return {
                      "status": "success",
                      "table": f"{schema}.{table_name}",
                      "action": "inserted",
                      "rows_affected": cur.rowcount,
                  }
      except Exception as e:
          return {"status": "error", "error": str(e)}