Hook Health Alert

Fast Path — Node Dispatch

Dispatches to node_platform_diagnostics for the HOOK_HEALTH dimension:

onex run node_platform_diagnostics -- --dimensions=HOOK_HEALTH

With dry-run (reads cached artifacts, no live HTTP):

onex run node_platform_diagnostics -- --dimensions=HOOK_HEALTH --dry-run

Returns ModelDiagnosticsResult with HOOK_HEALTH dimension status (PASS/WARN/FAIL),
error rate, actionable items.

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Purpose

Periodic check of hook error rates. Queries the omnidash API for hook health
summary, evaluates against thresholds, and fires Slack alerts when tier 1
(interpreter) or tier 2 (degraded) errors exceed the configured threshold.

Designed as a skill-based interim solution. Will migrate to an ONEX effect node
(consuming onex.evt.omniclaude.hook-health-error.v1 directly) when the
runtime node system is operational.

Execution

1. Query GET /api/hook-health/summary?window={window}m from omnidash
   (pending: omnidash endpoint not yet implemented; uses local hook_health_probe until then)
2. Evaluate:
   • Tier 1 (interpreter) errors > 0: CRITICAL alert (always)
   • Tier 2 (degraded) errors > threshold: WARNING alert
   • Tier 3 (intentional): dashboard only, no alert
   • Alert-channel liveness: probe_hook_health() folds in
     omniclaude.hooks.alert_channel.probe_alert_channel(). A configured
     channel that does not deliver sets alert_channel_status == "dead", makes
     hook health unhealthy, and is reported on the durable failure log plus a
     local (osascript / notify-send) notification — never through the dead
     channel itself. Result is cached ~1h, so the check costs one round trip per
     hour regardless of session count. Three states, not two: live, dead,
     not_configured.
3. If alert needed and not --dry-run:
   • Post to Slack via SLACK_BOT_TOKEN / SLACK_CHANNEL_ID — the sole
     channel (the incoming webhook is retired; no fallback)
   • Rate limit: one alert per stable alert identity per 30 minutes
   • Alert identity = {hook_name}:{error_tier}:{error_category}
   • Message format matches existing blocked_notifier.py Block Kit style
4. Log result to .onex_state/hook-health/last-check.json

Alert Format

:red_circle: Hook Health CRITICAL
Interpreter errors detected (N in last 5m)

Hook: pre_tool_use_authorization_shim
Category: import_error
Message: ImportError: cannot import name 'UTC'...
Python: 3.9.6 (expected 3.12+)

Action: Rebuild plugin venv -- `cd plugins/onex/lib && uv sync`

Scheduling

/hook-health-alert --schedule 5m

This creates a CronCreate job that runs the check every 5 minutes.