- 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 :
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
Response time
2x baseline info :
log only
- 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 ~/.claude/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