| name | canary-watch |
| description | Monitor deployed pages and APIs for post-deploy regressions in availability, console errors, and performance thresholds. |
Canary Watch — Post-Deploy Monitoring
When to Use
- After deploying to production or staging
- After merging a risky PR
- When you want to verify a fix actually fixed it
- Continuous monitoring during a launch window
- After dependency upgrades
How It Works
Monitors a deployed URL for regressions. Runs in a loop until stopped or until the watch window expires.
What It Watches
1. HTTP Status — is the page returning 200?
2. Console Errors — new errors that weren't there before?
3. Network Failures — failed API calls, 5xx responses?
4. Performance — LCP/CLS/INP regression vs baseline?
5. Content — did key elements disappear? (h1, nav, footer, CTA)
6. API Health — are critical endpoints responding within SLA?
Watch Modes
Quick check (default): single pass, report results
/canary-watch https://myapp.com
Sustained watch: check every N minutes for M hours
/canary-watch https://myapp.com --interval 5m --duration 2h
Diff mode: compare staging vs production
/canary-watch --compare https://staging.myapp.com https://myapp.com
Alert Thresholds
critical:
- HTTP status != 200
- Console error count > 5 (new errors only)
- LCP > 4s
- API endpoint returns 5xx
warning:
- LCP increased > 500ms from baseline
- CLS > 0.1
- New console warnings
- Response time > 2x baseline
info:
- Minor performance variance
- New network requests (third-party scripts added?)
Notifications
When a critical threshold is crossed:
- Desktop notification (macOS/Linux)
- Optional: Slack/Discord webhook
- Log to
~/.github/canary-watch.log
Output
## Canary Report — myapp.com — 2026-03-23 03:15 PST
### Status: HEALTHY ✓
| Check | Result | Baseline | Delta |
|-------|--------|----------|-------|
| HTTP | 200 ✓ | 200 | — |
| Console errors | 0 ✓ | 0 | — |
| LCP | 1.8s ✓ | 1.6s | +200ms |
| CLS | 0.01 ✓ | 0.01 | — |
| API /health | 145ms ✓ | 120ms | +25ms |
### No regressions detected. Deploy is clean.
Integration
Pair with:
/browser-qa for pre-deploy verification- Hooks: add as a PostToolUse hook on
git push to auto-check after deploys
- CI: run in GitHub Actions after deploy step
