Canary Watch

1---2name: canary-watch3description: Use this skill to monitor a deployed URL for regressions after deploys, merges, or dependency upgrades.4origin: ECC5---6 7# Canary Watch — Post-Deploy Monitoring8 9## When to Use10 11- After deploying to production or staging12- After merging a risky PR13- When you want to verify a fix actually fixed it14- Continuous monitoring during a launch window15- After dependency upgrades16 17## How It Works18 19Monitors a deployed URL for regressions. Runs in a loop until stopped or until the watch window expires.20 21### What It Watches22 23```241. HTTP Status — is the page returning 200?252. Console Errors — new errors that weren't there before?263. Network Failures — failed API calls, 5xx responses?274. Performance — LCP/CLS/INP regression vs baseline?285. Content — did key elements disappear? (h1, nav, footer, CTA)296. API Health — are critical endpoints responding within SLA?30```31 32### Watch Modes33 34**Quick check** (default): single pass, report results35```36/canary-watch https://myapp.com37```38 39**Sustained watch**: check every N minutes for M hours40```41/canary-watch https://myapp.com --interval 5m --duration 2h42```43 44**Diff mode**: compare staging vs production45```46/canary-watch --compare https://staging.myapp.com https://myapp.com47```48 49### Alert Thresholds50 51```yaml52critical:  # immediate alert53  - HTTP status != 20054  - Console error count > 5 (new errors only)55  - LCP > 4s56  - API endpoint returns 5xx57 58warning:   # flag in report59  - LCP increased > 500ms from baseline60  - CLS > 0.161  - New console warnings62  - Response time > 2x baseline63 64info:      # log only65  - Minor performance variance66  - New network requests (third-party scripts added?)67```68 69### Notifications70 71When a critical threshold is crossed:72- Desktop notification (macOS/Linux)73- Optional: Slack/Discord webhook74- Log to `~/.claude/canary-watch.log`75 76## Output77 78```markdown79## Canary Report — myapp.com — 2026-03-23 03:15 PST80 81### Status: HEALTHY ✓82 83| Check | Result | Baseline | Delta |84|-------|--------|----------|-------|85| HTTP | 200 ✓ | 200 | — |86| Console errors | 0 ✓ | 0 | — |87| LCP | 1.8s ✓ | 1.6s | +200ms |88| CLS | 0.01 ✓ | 0.01 | — |89| API /health | 145ms ✓ | 120ms | +25ms |90 91### No regressions detected. Deploy is clean.92```93 94## Integration95 96Pair with:97- `/browser-qa` for pre-deploy verification98- Hooks: add as a PostToolUse hook on `git push` to auto-check after deploys99- CI: run in GitHub Actions after deploy step