metrics

metrics is a skill for Claude Code, Codex from williamzujkowski/standards. It costs 13 tokens per session (442 once invoked), scanned A, a copy of logging, MIT.

A metrics guide for measuring application and service behaviour with numbers such as counts, rates, and timings.

In plain words
What is it for?
Use it when adding monitoring, choosing measurement patterns, handling errors, testing, and improving performance.
Why use it?
It helps teams spot changes, measure performance, and understand whether systems are working as expected.

Skill for Claude CodeCodex

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

Good fit Use it when adding monitoring, choosing measurement patterns, handling errors, testing, and improving performance.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/williamzujkowski/standards/metrics
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 williamzujkowski/standards --skill metrics
Clone the repo
git clone --depth 1 https://github.com/williamzujkowski/standards

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 metrics

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/williamzujkowski/standards/metrics"><img src="https://agentmods.dev/badge/skills/williamzujkowski/standards/metrics.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 13 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 442 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 91% 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 $0.00013 $0.00442
Opus 5.5 $0.00005 $0.00177
Sonnet 5.5 $0.00003 $0.00088
Haiku 4.5 $0.00001 $0.00044

Measured yesterday against content hash 821f108c29d1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-30, from the pricing page.

Security

Grade A, and why

metrics 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 yesterday.

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

91% identical to logging — 6 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.

skills/observability/metrics/SKILL.md · 84 lines

What it actually says

Metrics

Quick Navigation: Level 1: Quick Start (5 min) → Level 2: Implementation (30 min) → Level 3: Mastery (Extended)


Level 1: Quick Start

Core Principles

  1. Best Practices: Follow industry-standard patterns for observability
  2. Security First: Implement secure defaults and validate all inputs
  3. Maintainability: Write clean, documented, testable code
  4. Performance: Optimize for common use cases

Essential Checklist

  • Follow established patterns for observability
  • Implement proper error handling
  • Add comprehensive logging
  • Write unit and integration tests
  • Document public interfaces

Quick Links to Level 2


Level 2: Implementation

Core Concepts

This skill covers essential practices for observability.

Key areas include:

  • Architecture patterns
  • Implementation best practices
  • Testing strategies
  • Performance optimization

Implementation Patterns

Apply these patterns when working with observability:

  1. Pattern Selection: Choose appropriate patterns for your use case
  2. Error Handling: Implement comprehensive error recovery
  3. Monitoring: Add observability hooks for production

Common Pitfalls

Avoid these common mistakes:

  • Skipping validation of inputs
  • Ignoring edge cases
  • Missing test coverage
  • Poor documentation

Level 3: Mastery Resources

Reference Materials

Templates

See the templates/ directory for starter configurations.

External Resources

Consult official documentation and community best practices for observability.

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 84 lines · 13 tokens per session scan A 821f108c29d1

Subscribe to this mod's changes

metrics is a skill published in the GitHub repository williamzujkowski/standards (18 stars, last pushed 1mo ago), licensed MIT. It adds 13 tokens to every session and 442 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 91% identical to logging, differing in 6 lines, and is treated as a copy.

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