Transactional Boundary

# Transactional Boundary

Ensure all-or-nothing execution for multi-step operations.

## Category
Tool Execution

## Context
Operations that must succeed completely or not at all.

## Problem
Partial failures can leave data in inconsistent states.

## Solution
Define transactional boundaries:
- **Atomic**: All steps succeed or all roll back
- **Consistent**: Data integrity maintained
- **Isolated**: Intermediate states not visible
- **Durable**: Committed changes persist

## Example (Python)
```python
@tool
def transfer_funds(
    from_account: str,
    to_account: str,
    amount: float
) -> TransferResult:
    """Transfer funds atomically.
    
    Either both accounts are updated or neither is.
    No partial transfers possible.
    """
    with transaction():
        debit(from_account, amount)
        credit(to_account, amount)
    return TransferResult(success=True)
```

## Considerations
- Keep transactions as short as possible
- Document what's included in the transaction
- Use compensation for cross-system transactions

## Related Patterns
- compensation-handler
- idempotent-operation
- command-tool

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Source: https://arcade.dev/patterns/transactional-boundary