lighthouse

lighthouse is a skill for Claude Code, Codex from n-n-code/n-n-code-skills. It costs 71 tokens per session (1,452 once invoked), scanned A, original, MIT.

A skill for running and interpreting Google Lighthouse audits, which measure web-page performance, accessibility, common web practices, and search-engine optimization.

In plain words
What is it for?
It helps audit pages, compare reports, investigate findings, test logged-in user flows, and set Lighthouse CI thresholds that detect regressions.
Why use it?
It turns page-quality questions into repeatable measurements and helps identify and verify changes, including checks in automated build pipelines.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

Good fit It helps audit pages, compare reports, investigate findings, test logged-in user flows, and set Lighthouse CI thresholds that detect regressions.

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

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 lighthouse

README.md
[![agentmods](https://agentmods.dev/badge/skills/n-n-code/n-n-code-skills/lighthouse.svg)](https://agentmods.dev/skills/n-n-code/n-n-code-skills/lighthouse)
Your own site
<a href="https://agentmods.dev/skills/n-n-code/n-n-code-skills/lighthouse"><img src="https://agentmods.dev/badge/skills/n-n-code/n-n-code-skills/lighthouse.svg" alt="Measured on agentmods" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,452 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 $0.00071 $0.01452
Opus 5 $0.00036 $0.00726
Sonnet 5 $0.00014 $0.00290
Haiku 4.5 $0.00007 $0.00145

Measured today against content hash d2bde8c07c38, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

lighthouse 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 today.

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.

.agents/skills/lighthouse/SKILL.md · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Google Lighthouse

Turn a page-quality question into reproducible measurements, actionable findings, and verification appropriate to the claim. This is a portable workflow skill. It uses upstream Lighthouse and Lighthouse CI (LHCI), without a bundled runner or required host-specific interface. Reading an existing report needs no browser; native execution needs a compatible Node runtime, Lighthouse, and Chrome/Chromium. Scripted flows additionally need Puppeteer; CI collection needs LHCI.

Choose the job and owner

Requested job Work and output Change boundary
Interpret existing reports Explain findings, compare compatible evidence, identify gaps Read supplied artifacts; no new audit or source changes unless requested
Audit a URL or page state Execute the relevant measurement and retain local reports Browser activity and report files within the requested scope
Improve measured behavior Inspect causes, implement requested fixes, rebuild and remeasure Scoped source changes under existing authorization
Configure CI Establish collection, assertions, and artifact handling Requested tooling, configuration, and pipeline changes

Let this skill own Lighthouse measurement and interpretation. Use chrome-devtools-axi for general Chrome investigation and AXI execution rules; honor an explicitly chosen browser, wrapper, or direct tool interface. Use playwright-testing for existing Playwright tests and setup-playwright for their harness. Add matching implementation guidance or ui-guidance / ui-design-guidance when fixing code or reviewing broader UI/accessibility behavior. Add tester-mindset only when the validation strategy needs framing. These companions are optional; Lighthouse use alone does not require a harness.

Establish, measure, interpret, verify

  1. Establish the claim and inputs. Identify the requested job, URLs or report files, page states, device scope, authentication, and any existing baseline or budgets. Inspect repository scripts, lockfiles, Lighthouse/LHCI configuration, and CI before asking about facts already recorded there.
  2. Select a supported surface and mode. Prefer the CLI for reproducible URL audits and the Node API for scripted flows. Check versions, prerequisites, runtime help, and supported categories. A wrapper may expose only part of Lighthouse. Choose navigation for a page load, timespan for a bounded interaction, or snapshot for the current DOM state. Read execution and configuration before running; read authentication and flows when state or interactions matter.
  3. Define comparable conditions. For an unspecified URL audit, default to mobile navigation and the supported standard categories: performance, accessibility, best practices, and SEO. Prefer production assets and the repository's real startup contract. Record build/commit, Lighthouse and browser versions, mode, viewport/form factor, throttling, cache/storage, auth state, and material environment differences. Label development-build evidence when that is the relevant or only available target.
  4. Run and validate the capture. Use a fresh output prefix per attempt; save JSON and HTML where supported. Verify process status, report identity, time, actual destination/page state, runtime errors, and warnings before interpreting scores. A successful process or an existing file is insufficient. For performance comparisons, collect three sequential runs per variant on the same apparatus; keep failed attempts visible and report valid sample counts, medians, and variation. Increase sampling only when noise can change the conclusion. Do not run competing audits on the same machine.
  5. Interpret before proposing changes. Use reports and improvements. Separate measurements, observed resource/element evidence, and causal hypotheses. Distinguish absent, null, manual, informational, not-applicable, and error results. Check audit IDs against the report's version; missing legacy audits are not proof of a fix. Prioritize user impact and demonstrated causes.
  6. Act within the selected job. For improvement work, make the scoped fix, rebuild/restart owned services as needed, and repeat the same measurement plus relevant functional or UI checks. Stop at sufficient evidence for the requested outcome; explain noise, remaining issues, and blocked targets. For CI work, use Lighthouse CI; preserve established budgets and calibrate new hard gates from a baseline.
  7. Report and finish ownership. Provide the outcome, conditions, valid and failed runs, category scores and metric units, prioritized findings, verified changes, artifact paths, and remaining limits. Record the exact invocation or configuration needed to reproduce the result. Stop only owned processes and restore task-changed conditions in a reused session.

Read the full file on GitHub · 108 lines

Files

What ships with it

5 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. today First seen · 108 lines · 71 tokens per session scan A d2bde8c07c38

Subscribe to this mod's changes

lighthouse is a skill published in the GitHub repository n-n-code/n-n-code-skills (4 stars, last pushed yesterday), licensed MIT. It adds 71 tokens to every session and 1,452 once invoked, about $0.0004 per session on Opus 5. 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 2026-09-06.

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