CockroachDB MCP Server

Instructions

Returns:
    Transaction status.

Implementation Reference

• src/cockroachdb_mcp/server.py:378-389 (registration)

  Registration of the 'begin_transaction' MCP tool using @mcp.tool() decorator. Thin handler that delegates to connection_manager and handles exceptions.

  @mcp.tool()
  async def begin_transaction() -> dict[str, Any]:
      """Begin a database transaction.
  
      Returns:
          Transaction status.
      """
      try:
          return await connection_manager.begin_transaction()
      except Exception as e:
          return {"status": "error", "error": str(e)}

• src/cockroachdb_mcp/connection.py:248-266 (handler)

  Core implementation of begin_transaction in ConnectionManager class: ensures connection, checks for existing transaction, disables autocommit, updates state.

  async def begin_transaction(self) -> dict[str, Any]:
      """Begin a database transaction.
  
      Returns:
          Transaction status.
      """
      conn = await self.ensure_connected()
  
      if self._state.in_transaction:
          return {"status": "error", "error": "Transaction already in progress"}
  
      try:
          # Disable autocommit for transaction
          await conn.set_autocommit(False)
          self._state.in_transaction = True
          return {"status": "started", "message": "Transaction started"}
      except Exception as e:
          return {"status": "error", "error": str(e)}