/scan-disk — Minimal Domain Skill Example

The smallest useful Observe skill: it reads disk usage, records a baseline, and emits an alert when usage crosses a learned threshold. Use it as a 30-line template for your own domain. Every skill starts with a HALT check.

Step 0: Safety

ls agent/safety/HALT 2>/dev/null && echo "HALT_ACTIVE" || echo "HALT_INACTIVE"

If HALT is active, print the reason and stop immediately.

Step 1: Observe

df -P / | tail -1 | awk '{print $5}' | tr -d '%'   # → integer percent used

Load the lens (agent/state/disk_usage/lens.json) if present. Use its learned_thresholds for warn_pct if it has one; otherwise default warn_pct = 85.

Step 2: Record + alert

Write agent/state/disk_usage/state.json:

{
  "schema_version": "1.0.0",
  "last_run": "<now ISO-8601>",
  "status": "healthy",            // healthy | degraded | critical
  "metrics": { "used_pct": 73 },
  "alerts": []                    // e.g. ["disk 91% > warn_pct 85"] when crossed
}

Set status: "degraded" and add an alert when used_pct >= warn_pct; "critical" at >= 95. The evolve engine reads status/alerts during Observe and factors them into scoring.

Adaptive Lens (optional but recommended)

evolve's Step 5-E initializes and updates agent/state/disk_usage/lens.json automatically. To participate, just emit consistent metrics/alerts; the engine learns a per-host warn_pct over time (raising it on repeated false positives, lowering it after real incidents). You don't write the lens yourself.