SQL Server MCP

Instructions

Implementation Reference

• src/mssql_mcp/tools/crud.py:254-307 (handler)

  The main handler function for the 'delete_row' tool, decorated with @mcp.tool() for automatic registration with the MCP server. It deletes a specified row from a table using its primary key, handles errors, checks read-only mode, and returns a status dictionary.
  @mcp.tool() def delete_row(table: str, id: Any) -> dict[str, Any]: """Delete a row by primary key. Args: table: Table name (can include schema: 'dbo.Users' or 'Users') id: Primary key value of the row to delete Returns: Dictionary with: - status: 'deleted' or error - table: Full table name - id: The deleted row's ID - rows_affected: Number of rows deleted (should be 1) """ try: manager = get_connection_manager() config = manager.config # Check read-only mode if config.read_only: return {"error": "Delete operations disabled in read-only mode"} schema, table_name = parse_table_name(table) # Get primary key column pk_cols = _get_primary_key_columns(schema, table_name) if not pk_cols: return {"error": f"No primary key found for table {schema}.{table_name}"} # Build DELETE statement query = f"DELETE FROM [{schema}].[{table_name}] WHERE [{pk_cols[0]}] = %s" affected = manager.execute_non_query(query, (id,)) if affected == 0: return { "error": f"No row found with {pk_cols[0]} = {id}", "table": f"{schema}.{table_name}", } return { "status": "deleted", "table": f"{schema}.{table_name}", "id": id, "rows_affected": affected, } except QueryError as e: logger.error(f"Error deleting row from {table}: {e}") return {"error": str(e)} except Exception as e: logger.error(f"Unexpected error deleting row from {table}: {e}") return {"error": str(e)}
• src/mssql_mcp/tools/crud.py:14-39 (helper)

  Helper function used by delete_row (and other CRUD tools) to retrieve the primary key column names for a given table, essential for constructing the WHERE clause in the DELETE statement.
  def _get_primary_key_columns(schema: str, table: str) -> list[str]: """Get primary key column(s) for a table. Args: schema: Schema name table: Table name Returns: List of primary key column names """ manager = get_connection_manager() query = """ SELECT c.COLUMN_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE c ON tc.CONSTRAINT_NAME = c.CONSTRAINT_NAME AND tc.TABLE_SCHEMA = c.TABLE_SCHEMA AND tc.TABLE_NAME = c.TABLE_NAME WHERE tc.TABLE_SCHEMA = %s AND tc.TABLE_NAME = %s AND tc.CONSTRAINT_TYPE = 'PRIMARY KEY' ORDER BY c.ORDINAL_POSITION """ rows = manager.execute_query(query, (schema, table)) return [row["COLUMN_NAME"] for row in rows]
• src/mssql_mcp/tools/__init__.py:4-4 (registration)

  The __init__.py file imports the crud module, which triggers the execution of the @mcp.tool() decorators in crud.py, thereby registering the delete_row tool with the MCP server.
  from . import crud, databases, export, query, stored_procs, tables