canary
Post-deploy canary monitoring. Watches the live app for console errors, performance regressions, and page failures using the browse daemon. Takes periodic screenshots, compares against pre-deploy baselines, and alerts on anomalies. Use when: "monitor deploy", "canary", "post-depl
What it does
Preamble
eval "$(~/.vibestack/bin/vibe-slug 2>/dev/null)" 2>/dev/null || SLUG="unknown"
_LEARN_FILE="${VIBESTACK_HOME:-$HOME/.vibestack}/projects/${SLUG:-unknown}/learnings.jsonl"
if [ -f "$_LEARN_FILE" ]; then
_LEARN_COUNT=$(wc -l < "$_LEARN_FILE" 2>/dev/null | tr -d ' ')
echo "LEARNINGS: $_LEARN_COUNT entries loaded"
if [ "$_LEARN_COUNT" -gt 5 ] 2>/dev/null; then
~/.vibestack/bin/vibe-learnings-search --limit 5 2>/dev/null || true
fi
else
echo "LEARNINGS: none yet"
fi
SETUP
# vibestack does not include a browse daemon.
echo "BROWSE_NOT_AVAILABLE"
If BROWSE_NOT_AVAILABLE: skip all $B commands and use text-only fallbacks (curl, open, direct HTTP checks).
Step 0: Detect platform and base branch
First, detect the git hosting platform from the remote URL:
git remote get-url origin 2>/dev/null
- If the URL contains "github.com" → platform is GitHub
- If the URL contains "gitlab" → platform is GitLab
- Otherwise, check CLI availability:
gh auth status 2>/dev/nullsucceeds → platform is GitHub (covers GitHub Enterprise)glab auth status 2>/dev/nullsucceeds → platform is GitLab (covers self-hosted)- Neither → unknown (use git-native commands only)
Determine which branch this PR/MR targets, or the repo's default branch if no PR/MR exists. Use the result as "the base branch" in all subsequent steps.
If GitHub:
gh pr view --json baseRefName -q .baseRefName— if succeeds, use itgh repo view --json defaultBranchRef -q .defaultBranchRef.name— if succeeds, use it
If GitLab:
glab mr view -F json 2>/dev/nulland extract thetarget_branchfield — if succeeds, use itglab repo view -F json 2>/dev/nulland extract thedefault_branchfield — if succeeds, use it
Git-native fallback (if unknown platform, or CLI commands fail):
git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's|refs/remotes/origin/||'- If that fails:
git rev-parse --verify origin/main 2>/dev/null→ usemain - If that fails:
git rev-parse --verify origin/master 2>/dev/null→ usemaster
If all fail, fall back to main.
Print the detected base branch name. In every subsequent git diff, git log,
git fetch, git merge, and PR/MR creation command, substitute the detected
branch name wherever the instructions say "the base branch" or <default>.
/canary — Post-Deploy Visual Monitor
You are a Release Reliability Engineer watching production after a deploy. You've seen deploys that pass CI but break in production — a missing environment variable, a CDN cache serving stale assets, a database migration that's slower than expected on real data. Your job is to catch these in the first 10 minutes, not 10 hours.
You use the browse daemon to watch the live app, take screenshots, check console errors, and compare against baselines. You are the safety net between "shipped" and "verified."
User-invocable
When the user types /canary, run this skill.
Arguments
/canary <url>— monitor a URL for 10 minutes after deploy/canary <url> --duration 5m— custom monitoring duration (1m to 30m)/canary <url> --baseline— capture baseline screenshots (run BEFORE deploying)/canary <url> --pages /,/dashboard,/settings— specify pages to monitor/canary <url> --quick— single-pass health check (no continuous monitoring)
Instructions
Phase 1: Setup
eval "$(~/.vibestack/bin/vibe-slug 2>/dev/null || echo "SLUG=unknown")"
mkdir -p .vibestack/canary-reports
mkdir -p .vibestack/canary-reports/baselines
mkdir -p .vibestack/canary-reports/screenshots
Parse the user's arguments. Default duration is 10 minutes. Default pages: auto-discover from the app's navigation.
Phase 2: Baseline Capture (--baseline mode)
If the user passed --baseline, capture the current state BEFORE deploying.
For each page (either from --pages or the homepage):
$B goto <page-url>
$B snapshot -i -a -o ".vibestack/canary-reports/baselines/<page-name>.png"
$B console --errors
$B perf
$B text
Collect for each page: screenshot path, console error count, page load time from perf, and a text content snapshot.
Save the baseline manifest to .vibestack/canary-reports/baseline.json:
{
"url": "<url>",
"timestamp": "<ISO>",
"branch": "<current branch>",
"pages": {
"/": {
"screenshot": "baselines/home.png",
"console_errors": 0,
"load_time_ms": 450
}
}
}
Then STOP and tell the user: "Baseline captured. Deploy your changes, then run /canary <url> to monitor."
Phase 3: Page Discovery
If no --pages were specified, auto-discover pages to monitor:
$B goto <url>
$B links
$B snapshot -i
Extract the top 5 internal navigation links from the links output. Always include the homepage. Present the page list via AskUserQuestion:
- Context: Monitoring the production site at the given URL after a deploy.
- Question: Which pages should the canary monitor?
- RECOMMENDATION: Choose A — these are the main navigation targets.
- A) Monitor these pages: [list the discovered pages]
- B) Add more pages (user specifies)
- C) Monitor homepage only (quick check)
Phase 4: Pre-Deploy Snapshot (if no baseline exists)
If no baseline.json exists, take a quick snapshot now as a reference point.
For each page to monitor:
$B goto <page-url>
$B snapshot -i -a -o ".vibestack/canary-reports/screenshots/pre-<page-name>.png"
$B console --errors
$B perf
Record the console error count and load time for each page. These become the reference for detecting regressions during monitoring.
Phase 5: Continuous Monitoring Loop
Monitor for the specified duration. Every 60 seconds, check each page:
$B goto <page-url>
$B snapshot -i -a -o ".vibestack/canary-reports/screenshots/<page-name>-<check-number>.png"
$B console --errors
$B perf
After each check, compare results against the baseline (or pre-deploy snapshot):
- Page load failure —
gotoreturns error or timeout → CRITICAL ALERT - New console errors — errors not present in baseline → HIGH ALERT
- Performance regression — load time exceeds 2x baseline → MEDIUM ALERT
- Broken links — new 404s not in baseline → LOW ALERT
Alert on changes, not absolutes. A page with 3 console errors in the baseline is fine if it still has 3. One NEW error is an alert.
Don't cry wolf. Only alert on patterns that persist across 2 or more consecutive checks. A single transient network blip is not an alert.
If a CRITICAL or HIGH alert is detected, immediately notify the user via AskUserQuestion:
CANARY ALERT
════════════
Time: [timestamp, e.g., check #3 at 180s]
Page: [page URL]
Type: [CRITICAL / HIGH / MEDIUM]
Finding: [what changed — be specific]
Evidence: [screenshot path]
Baseline: [baseline value]
Current: [current value]
- Context: Canary monitoring detected an issue on [page] after [duration].
- RECOMMENDATION: Choose based on severity — A for critical, B for transient.
- A) Investigate now — stop monitoring, focus on this issue
- B) Continue monitoring — this might be transient (wait for next check)
- C) Rollback — revert the deploy immediately
- D) Dismiss — false positive, continue monitoring
Phase 6: Health Report
After monitoring completes (or if the user stops early), produce a summary:
CANARY REPORT — [url]
═════════════════════
Duration: [X minutes]
Pages: [N pages monitored]
Checks: [N total checks performed]
Status: [HEALTHY / DEGRADED / BROKEN]
Per-Page Results:
─────────────────────────────────────────────────────
Page Status Errors Avg Load
/ HEALTHY 0 450ms
/dashboard DEGRADED 2 new 1200ms (was 400ms)
/settings HEALTHY 0 380ms
Alerts Fired: [N] (X critical, Y high, Z medium)
Screenshots: .vibestack/canary-reports/screenshots/
VERDICT: [DEPLOY IS HEALTHY / DEPLOY HAS ISSUES — details above]
Save report to .vibestack/canary-reports/{date}-canary.md and .vibestack/canary-reports/{date}-canary.json.
Log the result for the review dashboard:
eval "$(~/.vibestack/bin/vibe-slug 2>/dev/null)"
mkdir -p ~/.vibestack/projects/$SLUG
Write a JSONL entry: {"skill":"canary","timestamp":"<ISO>","status":"<HEALTHY/DEGRADED/BROKEN>","url":"<url>","duration_min":<N>,"alerts":<N>}
Phase 7: Baseline Update
If the deploy is healthy, offer to update the baseline:
- Context: Canary monitoring completed. The deploy is healthy.
- RECOMMENDATION: Choose A — deploy is healthy, new baseline reflects current production.
- A) Update baseline with current screenshots
- B) Keep old baseline
If the user chooses A, copy the latest screenshots to the baselines directory and update baseline.json.
Important Rules
- Speed matters. Start monitoring within 30 seconds of invocation. Don't over-analyze before monitoring.
- Alert on changes, not absolutes. Compare against baseline, not industry standards.
- Screenshots are evidence. Every alert includes a screenshot path. No exceptions.
- Transient tolerance. Only alert on patterns that persist across 2+ consecutive checks.
- Baseline is king. Without a baseline, canary is a health check. Encourage
--baselinebefore deploying. - Performance thresholds are relative. 2x baseline is a regression. 1.5x might be normal variance.
- Read-only. Observe and report. Don't modify code unless the user explicitly asks to investigate and fix.
Capabilities
Install
Quality
deterministic score 0.46 from registry signals: · indexed on github topic:agent-skills · 15 github stars · SKILL.md body (9,652 chars)