| name | lighthouse-pagespeed-stinger |
| description | Lighthouse + PageSpeed Insights specialist for React/Next.js stacks. Covers running Lighthouse locally vs in CI (LHCI, GitHub Actions), all four audit categories (Performance, Accessibility, Best Practices, SEO), score budgets and performance budgets, the Lighthouse lab-vs-CrUX field-data gap (including the TBT/INP limitation), and performance tracking over time with Treo, SpeedCurve, or a self-hosted LHCI server. Use when the user says "set up Lighthouse CI", "add a performance budget to CI", "my Lighthouse score differs from CrUX", "compare Treo vs SpeedCurve", "write a custom Lighthouse plugin", "my field INP is bad but TBT is fine", "configure LHCI for GitHub Actions", "audit our site with Lighthouse", or when `lighthouse-pagespeed-worker-bee` is invoked. Do NOT use for SEO content strategy or keyword research (seo-aeo-worker-bee), accessibility remediation beyond Lighthouse-surfaced findings (future a11y Bee), or Core Web Vitals optimization implementation (react-worker-bee / performance-optimizer). |
lighthouse-pagespeed-stinger
Opinionated playbook for running Lighthouse and PageSpeed Insights correctly — in CI, locally, and as part of a long-term performance tracking strategy. Synthesized from the Lighthouse 12.6.1 + LHCI 0.15.x canon, the web.dev lab-vs-field framework, and 2025-2026 practitioner patterns.
Read first: guides/00-runner-selection.md — the decision tree for which tool to use before you touch any config.
When to use this skill
Load this skill when lighthouse-pagespeed-worker-bee is invoked. Trigger phrases:
- "Set up Lighthouse CI / LHCI"
- "Add a performance budget to our CI pipeline"
- "My Lighthouse score is 90 but CrUX says I'm failing LCP"
- "Configure Lighthouse for GitHub Actions"
- "What's the difference between TBT and INP?"
- "Compare Treo vs SpeedCurve for monitoring"
- "Write a custom Lighthouse plugin"
- "Audit this URL with Lighthouse"
- "Set a performance budget"
Do NOT load for:
- SEO content strategy, keyword research, or metadata optimization (route to
seo-aeo-worker-bee)
- Core Web Vitals implementation fixes like image optimization or JS bundle reduction (route to
react-worker-bee or performance-optimizer)
- Accessibility design decisions beyond Lighthouse-flagged technical issues
- CI/CD pipeline topology beyond the Lighthouse-specific configuration step (route to
devops-worker-bee)
Critical directives
These are non-negotiables. They protect reproducibility, team trust, and the lab-vs-field mental model.
-
Always specify throttling and form-factor explicitly. A mobile simulation at 4x CPU / 1.6 Mbps and a desktop no-throttle run produce completely different scores; mixing them corrupts trend data. See guides/00-runner-selection.md.
-
Run at least three passes; report the median. LHCI defaults to three runs for this reason (numberOfRuns: 3). A single Lighthouse run has high variance due to non-deterministic CPU and network simulation. See guides/01-lhci-configuration.md.
-
Always present both lab scores and CrUX field data when PSI API data is available. Lab data reflects ideal conditions; field data (p75) reflects real users. The gap between them is often the most actionable signal. See guides/02-lab-vs-field.md.
-
Never set a score budget below the current production baseline without a remediation plan. Measure first (lhci autorun without assertions), document baselines, then add a 10-20% buffer. A budget that gates CI on day one with no remediation plan blocks deploys without unblocking the team. See guides/01-lhci-configuration.md.
-
TBT is an imperfect proxy for INP. A good TBT does not guarantee a good INP. INP measures full interaction latency (delay + processing + presentation). TBT only captures blocking tasks during load. A page can have TBT < 200ms and INP > 500ms. Always check field INP separately. See guides/02-lab-vs-field.md.
-
Scope custom plugins to audits that existing Lighthouse audits cannot cover. Plugins cannot access custom Gatherers; they can only read existing artifacts (ImageElements, ScriptElements, devtoolsLogs, etc.). If you need custom page data, you need a full custom config. See guides/05-custom-plugins.md.
Lighthouse 12 / LHCI 0.15.x facts (encoded from research)
Source: research/external/2026-05-20-lighthouse-performance-scoring.md
Current version: Lighthouse 12.6.1 (LHCI 0.15.x). Node 18+ required.
Four categories (not five — PWA removed in LH12, May 2024):
- Performance
- Accessibility
- Best Practices
- SEO
Performance score weights (unchanged from LH10):
| Metric | Weight |
|---|
| Total Blocking Time (TBT) | 30% |
| Largest Contentful Paint (LCP) | 25% |
| Cumulative Layout Shift (CLS) | 25% |
| First Contentful Paint (FCP) | 10% |
| Speed Index (SI) | 10% |
INP is NOT in the Lighthouse Performance score. INP replaced FID as a Core Web Vital (March 12, 2024), but INP is a field-only metric. TBT is its lab proxy. TTI was removed from the score in Lighthouse 10.
Score color bands: 0-49 red (Poor), 50-89 orange (Needs Improvement), 90-100 green (Good). Reaching 90+ means being in the top 8% of HTTP Archive sites for that metric.
Guide map
Each guide is a self-contained instruction set. Read in order on first use; jump directly to the relevant guide for targeted tasks.
| Guide | When to read |
|---|
guides/00-runner-selection.md | First — before choosing any tool |
guides/01-lhci-configuration.md | Setting up lighthouserc.json/yaml, collect/assert/upload |
guides/02-lab-vs-field.md | Reconciling Lighthouse scores vs CrUX / PSI field data |
guides/03-ci-integration.md | GitHub Actions workflow, LHCI setup, score gating |
guides/04-performance-tracking.md | Treo, SpeedCurve, self-hosted LHCI server |
guides/05-custom-plugins.md | Authoring custom Lighthouse audit plugins |
guides/06-audit-category-glossary.md | Understanding individual audits and their score weights |
Templates
templates/lighthouserc-starter.yaml — Annotated production-ready LHCI configtemplates/custom-plugin-starter.js — Scaffold for a custom Lighthouse plugin
Examples
examples/happy-path-lhci-setup.md — End-to-end LHCI setup from zero to CI-gating a Next.js appexamples/lab-field-reconciliation.md — Walking through a case where Lighthouse scores 90 but CrUX INP fails
Reports
reports/README.md — Report template and location convention for audit reports
Command Brief: ai-tools/command-briefs/lighthouse-pagespeed-worker-bee-command-brief.md
Research: research/research-summary.md (normal depth, 9 sources, May 2026)
Forged by stinger-forge as part of the Legion AI Tools Factory by Mario Aldayuz a.k.a @thenotoriousllama
