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Get Started Free →Use this skill to monitor and verify a deployed URL after releases — checks HTTP endpoints, SSE streams, static assets, console errors, and performance regressions after deploys, merges, or dependency upgrades. Smoke / canary / post-deploy verification.
.claude/skills/canary-watch/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-17 | ✗→✓ | ▲ Improved | — | — |
| case-01 | ✗→✓ | ▲ Improved | — | — |
| case-14 | ✗→✓ | ▲ Improved | — | — |
| case-06 | ✗→✓ | ▲ Improved | — | — |
| case-04 | ✗→✓ | ▲ Improved | — | — |
Monitors a deployed URL for regressions. Runs in a loop until stopped or until the watch window expires.
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?
7. Static Assets — are JS, CSS, image, and font requests returning 2xx/3xx with expected content types?
8. SSE Streams — do event-stream endpoints connect and receive an initial event or heartbeat?Quick check (default): single pass, report results
/canary-watch https://myapp.comSustained watch: check every N minutes for M hours
/canary-watch https://myapp.com --interval 5m --duration 2hDiff mode: compare staging vs production
/canary-watch --compare https://staging.myapp.com https://myapp.comyamlcritical: # immediate alert - HTTP status != 200 - Console error count > 5 (new errors only) - LCP > 4s - API endpoint returns 5xx - Static asset returns 4xx/5xx - SSE endpoint cannot connect or drops before first heartbeat warning: # flag in report - LCP increased > 500ms from baseline - CLS > 0.1 - New console warnings - Response time > 2x baseline - Static asset content type changed unexpectedly - SSE heartbeat latency > 2x baseline info: # log only - Minor performance variance - New network requests (third-party scripts added?)
When a critical threshold is crossed:
~/.claude/canary-watch.logmarkdown## 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 | | Static assets | 42/42 ✓ | 42/42 | — | | SSE /events | connected ✓ | connected | +80ms heartbeat | ### No regressions detected. Deploy is clean.
Pair with:
/browser-qa for pre-deploy verificationgit push to auto-check after deploys| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-20 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-17 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-01 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-03 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-05 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-14 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-06 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-04 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-07 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-19 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-15 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-13 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-10 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-12 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-18 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-22 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-16 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-09 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-11 | fail→pass | — | — | — | — | — | — | — | — | — | — | — | — |
case-02 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-21 | fail→fail | — | — | — | — | — | — | — | — | — | — | — | — |
case-08 | pass→pass | — | — | — | — | — | — | — | — | — | — | — | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted. The headline lift of +59 percentage points is the difference between those two pass rates over the 22 comparable cases.
The per-case answers from this run were removed by the retention sweep, so the case table below shows the verdicts without the text either arm produced. The counts above were recorded at the time and are unaffected. Answers are now kept for 180 days.
Other measured skills in the registry, with their headline benchmark lift.