Health Check

# Health Check

Verify tool availability before relying on it.

## Category
Tool Discovery

## Context
Tools that depend on external services.

## Problem
Agents waste time attempting to use unavailable tools.

## Solution
Provide health check capability:
- **Lightweight probe**: Fast availability check
- **Dependency status**: Are backends reachable?
- **Degraded mode**: What still works if partial?

## Example (Python)
```python
@tool
def check_service_health(
    service: str | None = None
) -> HealthStatus:
    """Check if services are available.
    
    Args:
        service: Specific service or None for all
    
    Returns status: healthy, degraded, or unavailable.
    """
    return health_checker.check(service)
```

## Considerations
- Make health checks fast (sub-second)
- Return specific failure reasons
- Consider caching health status briefly

## Related Patterns
- fallback-tool
- graceful-degradation
- tool-registry

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Source: https://arcade.dev/patterns/health-check