cks-canary

name	cks:canary
description	Post-deploy canary verification domain knowledge — console errors, page load, pass/fail criteria
allowed-tools	["Bash","Write"]

Canary — Post-Deploy Browser Verification

What a Canary Check Verifies

1. Page loads — URL responds, no network failure
2. Console errors — no ERROR-level browser console messages
3. Obvious failure signals — page title/h1 does not contain "Error", "404", "500", "Not Found", "Something went wrong", "Internal Server Error"
4. Visual sanity — page renders content (not blank, not spinner-only)

Pass / Fail / Warning Criteria

Result	Condition
PASS	No console ERRORs. Page loads. No failure keywords in title/h1.
FAIL	Any console ERROR. Page fails to load. Failure keyword in title/h1.
PASS_WITH_WARNINGS	Console WARNs only. Page loads fine otherwise.

Warnings do not block deploy. Errors do.

Console Level Definitions

• ERROR — Always a FAIL signal. Unhandled exceptions, network failures, script errors.
• WARN — Flag as warning, do not fail. Deprecated API usage, fallback paths.
• INFO / LOG — Ignore for canary purposes.

Failure Keyword Scan

Check title tag and first <h1> for (case-insensitive):

• 404, 500, 503
• not found, page not found
• error, something went wrong
• internal server error
• forbidden, unauthorized (if URL is meant to be public)

Output Format

Brief. Lead with verdict. Show errors if any.

Canary: https://example.com
Status: PASS
Console errors: 0
Result saved: .cks/canary-last.json

Or on failure:

Canary: https://example.com
Status: FAIL
Console errors: 2
  - TypeError: Cannot read property 'x' of undefined (app.js:142)
  - Failed to load resource: 500 /api/health
Result saved: .cks/canary-last.json

Result File Schema

.cks/canary-last.json:

{
  "url": "https://example.com",
  "timestamp": "2024-01-15T10:30:00Z",
  "status": "pass",
  "error_count": 0,
  "errors": [],
  "warnings": ["Deprecated: componentWillMount"]
}

Common Rationalizations

Rationalization	Reality
"The deploy script said success, that's enough"	Deploy success = files transferred. Canary = app actually works. Both required.
"Console warns are fine to ignore"	Warns = PASS_WITH_WARNINGS, not FAIL. But log them — they compound.
"The page loaded, no need to check console"	Invisible JS errors break user flows silently. Check console always.

Verification

• URL navigated successfully
• Console messages read and filtered
• Page text scanned for failure keywords
• Verdict matches criteria table above
• .cks/canary-last.json written with correct schema