canary

canary is a skill for Claude Code, Codex from rijuvashisht/Magneto. It costs 0 tokens per session (330 once invoked), scanned A, original, MIT.

A post-deployment monitoring workflow for a live website. It compares the new version with a baseline and checks page speed, browser errors, network failures, and feature-flag problems for 30 to 60 minutes.

In plain words
What is it for?
Use it to monitor key pages after deployment, alert on anomalies through configured channels, and optionally roll back a release when a critical problem appears.
Why use it?
It helps detect regressions shortly after a release, when a newly introduced problem can affect users.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to monitor key pages after deployment, alert on anomalies through configured channels, and optionally roll back a release when a critical problem appears.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rijuvashisht/magneto/canary
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 rijuvashisht/Magneto --skill canary
Clone the repo
git clone --depth 1 https://github.com/rijuvashisht/Magneto

Made for: Claude Code, Codex.

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/rijuvashisht/magneto/canary/github.svg)](https://agentmods.dev/skills/rijuvashisht/magneto/canary)
Your own site
<a href="https://agentmods.dev/skills/rijuvashisht/magneto/canary"><img src="https://agentmods.dev/badge/skills/rijuvashisht/magneto/canary/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

Your own site · 80×15
<a href="https://agentmods.dev/skills/rijuvashisht/magneto/canary"><img src="https://agentmods.dev/badge/skills/rijuvashisht/magneto/canary.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 330 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 original No closer match found 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 $0.00000 $0.00330
Opus 5 $0.00000 $0.00165
Sonnet 5 $0.00000 $0.00066
Haiku 4.5 $0.00000 $0.00033

Measured 12d ago against content hash c3021620cb07, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

canary 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 12d 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.

src/templates/magneto-skills/skills/canary/SKILL.md · 47 lines

What it actually says

/canary — Post-Deploy Monitoring Loop

Role: SRE Inputs: deployed URL Outputs: continuous monitoring report; alerts on anomalies Audit actions: canary.started, canary.anomaly_detected, canary.cleared


What This Skill Does

For the first 30–60 minutes after a deploy, actively monitor for:

  • Console errors (new types not seen pre-deploy)
  • Performance regressions (p95 page load > baseline × 1.5)
  • Network errors (new 4xx/5xx rates)
  • Feature flag misfires

Protocol

Step 1: Baseline

Run magneto browse against the previous deploy (or staging) to capture baseline metrics:

  • Page load times
  • Console message counts by level
  • Network request counts

Step 2: Loop

Every 5 minutes for the configured window:

  1. Visit key pages via headless browser
  2. Capture metrics
  3. Diff vs baseline
  4. If anomaly exceeds threshold, emit audit canary.anomaly_detected and alert

Step 3: Alert channels

Configured via .magneto/canary.json:

  • Slack webhook
  • PagerDuty
  • Email
  • Terminal-only (default)

Step 4: Auto-rollback (opt-in)

If autoRollback: true and critical anomaly detected, run the rollback command and emit audit canary.rollback_triggered.

Trigger Phrases

  • "canary"
  • "monitor prod"
  • "watch the deploy"
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. 12d ago First seen · 47 lines · 0 tokens per session scan A c3021620cb07

Subscribe to this mod's changes

canary is a skill published in the GitHub repository rijuvashisht/Magneto (6 stars, last pushed 2mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 330 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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