canary-watch

name	canary-watch
description	Post-deploy monitoring -- watches deployed URLs for regressions in HTTP status, console errors, performance, content, and API health.
origin	ECC

Canary Watch -- Post-Deploy Monitoring

Monitors a deployed URL for regressions after deployment.

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

What It Watches

1. HTTP Status -- is the page returning 200?
2. Console Errors -- new errors that were not there before?
3. Network Failures -- failed API calls, 5xx responses?
4. Performance -- LCP/CLS/INP regression vs baseline?
5. Content -- did key elements disappear?
6. API Health -- are critical endpoints responding within SLA?

Watch Modes

• Quick check (default): single pass, report results
• Sustained watch: check every N minutes for M hours
• Diff mode: compare staging vs production

Alert Thresholds

Critical (immediate alert)

• HTTP status != 200
• Console error count > 5 (new errors only)
• LCP > 4s
• API endpoint returns 5xx

Warning (flag in report)

• LCP increased > 500ms from baseline
• CLS > 0.1
• New console warnings

Output

## Canary Report -- myapp.com

| Check | Result | Baseline | Delta |
|-------|--------|----------|-------|
| HTTP | 200 | 200 | -- |
| Console errors | 0 | 0 | -- |
| LCP | 1.8s | 1.6s | +200ms |
| API /health | 145ms | 120ms | +25ms |

### No regressions detected. Deploy is clean.

Integration

Pair with /browser-qa for pre-deploy verification.