Audit Trail

# Audit Trail

Log all tool invocations for security and debugging.

## Category
Tool Security

## Context
Any production tool system.

## Problem
Without logs, you can't debug issues or detect abuse.

## Solution
Comprehensive audit logging:
- **What**: Tool name, parameters (redacted)
- **Who**: User ID, session ID
- **When**: Timestamp
- **Result**: Success/failure, duration

## Example (Python)
```python
@tool
def update_record(
    context: Context,
    record_id: str,
    **updates
) -> UpdateResult:
    """Update a record with full audit trail."""
    audit_log.record(
        tool="update_record",
        user_id=context.user.id,
        session_id=context.session.id,
        parameters=redact_sensitive({"record_id": record_id, **updates}),
        timestamp=datetime.utcnow()
    )
    
    try:
        result = records_api.update(record_id, **updates)
        audit_log.record_result(success=True, duration=elapsed)
        return result
    except Exception as e:
        audit_log.record_result(success=False, error=str(e))
        raise
```

## Considerations
- Redact sensitive data before logging
- Include enough context for debugging
- Set appropriate retention periods

## Related Patterns
- secret-injection
- permission-gate
- identity-anchor

---
Source: https://arcade.dev/patterns/audit-trail