pagespeed-enhancer – Marketing & SEO skill for AI agents

PageSpeed Enhancer Skill

A structured, batch-wise audit-and-fix workflow for all four Lighthouse pillars. Always follow the batch flow in order. Never jump straight to fixes without completing the scan and risk assessment phases.

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Detailed Guide

Read [the detailed guide](references/detailed-guide.md) before executing this skill. It retains the complete procedure and reference material. Treat its safety, prerequisites, and validation requirements as mandatory. For focused work, load the relevant sections; for end-to-end work, read the guide completely.

When to Use This Skill

• User pastes a PageSpeed Insights report or mentions Lighthouse scores
• User asks to improve Core Web Vitals (LCP, INP, CLS) or lab diagnostics (FCP, TBT, SI)
• User needs help with render-blocking resources, unused JavaScript, image optimisation, security headers, ARIA compliance, or SEO meta-tag fixes
• User asks "why is my LCP slow", "fix accessibility issues", "improve my SEO score", or "my site scores 80 on performance"
• Any mention of PageSpeed, Lighthouse, Web Vitals, or site speed

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Examples

Example 1: User pastes a PageSpeed report

User: "My site scores 65 on Performance. LCP is 4.2s."

Agent:

1. Parses the score summary table — identifies LCP as critical bottleneck

2. Runs Batch A scan — finds lazy-loaded hero image and render-blocking CSS

3. Outputs risk report: F1.1 (CSS @import → link) ranked P1, F1.5 (LCP image eager) ranked P1

4. Applies Fix Batch 1, verifies with re-test

Example 2: User asks about slow LCP

User: "Why is my LCP slow?"

Agent:

1. Asks for a PageSpeed report URL or pasted results

2. Runs LCP-specific audit from Batch A — checks TTFB, element render delay, lazy loading

3. Identifies the LCP element, its current loading strategy, and the critical path chain

4. Recommends targeted fix (preload, eager loading, or server response time improvement)

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Limitations

• Does not run actual Lighthouse or PageSpeed tests — the user must provide the report or URL
• Security header recommendations assume the user controls the deployment platform (Netlify, Vercel, etc.)
• Fixes are general patterns; exact file paths and config syntax may vary by project setup
• Does not cover server-level optimisations (CDN config, PHP opcode caching, database queries, etc.)
• Image conversion commands assume the user has the required tools installed (cwebp, sharp, Pillow)
• CSP guidance uses a report-only iterative approach — the final policy must be tuned to each project's actual resource origins

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Measurement and rollout limits

Core Web Vitals are LCP, INP and CLS, assessed with field data at the 75th percentile; Lighthouse lab metrics and a 100 accessibility score are not field performance or WCAG certification. Record report date/version/device and distinguish observed causes from hypotheses. Numeric improvement examples are illustrative, not expected results for the current site.

CSP/COOP/Permissions-Policy can break integrations; merge with actual deployment config and test authentication, popups, camera/geolocation and embedding before enforcement. HSTS subdomains/preload require domain-wide readiness and can persist beyond rollback. The sample report-only CSP contains unsafe-inline and lacks a reporting destination; it is neither a finished XSS defense nor telemetry until configured. Inline stylesheet onload handlers may be blocked by the intended CSP; keep critical styles synchronous and avoid flashes of unstyled content. Font redistribution requires its license. Preserve source assets when converting/resizing. Public audit services and sitemap submission disclose URLs and need the relevant authorization. Missing upstream references do not block independent documented checks. No audit, conversion, deployment or browser test was run.