canary-watch

canary-watch is a skill for Claude Code from nklofy/code-agent-skills. It costs 54 tokens per session (828 once invoked), scanned A, a copy of canary-watch, Apache-2.0.

A tool for checking a deployed website or service after a release, merge, or dependency update, either once or repeatedly during a launch window.

In plain words
What is it for?
Use it for staging or production smoke checks and ongoing monitoring. It checks HTTP responses, APIs, network calls, JavaScript errors, key content, static files, performance, and server-sent event connections.
Why use it?
It catches regressions that code tests may miss, such as broken requests, console errors, missing page elements, failed assets, performance problems, or unhealthy live streams.

Skill for Claude Code

Written for Claude Code: PostToolUse hook event. Also seen: reads .claude/ paths.

Good fit Use it for staging or production smoke checks and ongoing monitoring. It checks HTTP responses, APIs, network calls, JavaScript errors, key content, static files, performance, and server-sent event connections.

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Install with agentmods
npx agentmods add skills/nklofy/code-agent-skills/canary-watch
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add nklofy/code-agent-skills --skill canary-watch
Clone the repo
git clone --depth 1 https://github.com/nklofy/code-agent-skills

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for canary-watch

README.md
[![agentmods](https://agentmods.dev/badge/skills/nklofy/code-agent-skills/canary-watch/github.svg)](https://agentmods.dev/skills/nklofy/code-agent-skills/canary-watch)
Your own site
<a href="https://agentmods.dev/skills/nklofy/code-agent-skills/canary-watch"><img src="https://agentmods.dev/badge/skills/nklofy/code-agent-skills/canary-watch/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for canary-watch

Your own site · 80×15
<a href="https://agentmods.dev/skills/nklofy/code-agent-skills/canary-watch"><img src="https://agentmods.dev/badge/skills/nklofy/code-agent-skills/canary-watch.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 828 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 89% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00054 $0.00828
Opus 5 $0.00027 $0.00414
Sonnet 5 $0.00011 $0.00166
Haiku 4.5 $0.00005 $0.00083

Measured 9d ago against content hash d2cb536f8ccb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

canary-watch scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

89% identical to canary-watch — 29 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

affaan-m-ECC/canary-watch/SKILL.md · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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?
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?

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
  - 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?)

Notifications

When a critical threshold is crossed:

  • Desktop notification (macOS/Linux)
  • Optional: Slack/Discord webhook
  • Log to ~/.claude/canary-watch.log

Read the full file on GitHub · 109 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 109 lines · 54 tokens per session scan A d2cb536f8ccb

Subscribe to this mod's changes

canary-watch is a skill published in the GitHub repository nklofy/code-agent-skills (18 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 54 tokens to every session and 828 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to canary-watch, differing in 29 lines, and is treated as a copy.

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