Evidence record · captured 2026-10-11

Web Performance Audit

Runs a Core Web Vitals / Lighthouse-style performance audit: the agent first discovers which browser/performance MCP tools are available (e.g. Chrome DevTools MCP), collects traces where possible, and retrieves current thresholds from web.dev and Chrome docs rather than quoting from memory. If trace tools are missing it does source and network analysis and states which measurements it could not collect.

Community publisherUnverifiedSource reviewedBehavior not tested

Source review

Editorial assessment

This is a source-only assessment. It does not claim runtime or security testing.

What it does

It turns a vague request to speed up a site into a five-phase audit driven by Chrome DevTools MCP tool calls, with rules that force quantified, specific recommendations and a fixed report format.

Best for

Diagnosing poor LCP, CLS, or INP on a page you can load in a browser
Producing a prioritized fix list with estimated savings for a site you also have source access to
Quick checks of whether a page is already fast enough to leave alone

Strengths in the source

Names the exact DevTools MCP calls per phase, from performance_start_trace with reload to performance_analyze_insight with LCPBreakdown or CLSCulprits.
Tells the agent to skip issues with 0ms estimated impact and to confirm an asset is unused before recommending removal.
If trace tools are missing, it continues with source and network analysis and states which measurements it could not collect.
Adds a codebase phase that detects the bundler and checks tree-shaking, polyfills, and minification, skipped for third-party sites.

Limitations

Full measurements need a Chrome DevTools MCP server, which the skill may suggest adding to the client's MCP configuration.
It tells the agent to retrieve thresholds from web.dev, yet the file also hardcodes threshold values that can go stale.
Not Cloudflare-specific despite its home repo, and the accessibility phase is a high-level snapshot, not an accessibility audit.

When not to use it

Backend or Worker CPU problems, which the workers-profiling skill addresses.
Formal accessibility compliance work, which needs a dedicated audit.

Reviewed by Retenta editorial on 2026-10-11; scope: source only.

Files included in this review

skills/web-perf/SKILL.md

Evidence and boundaries

Execution · not tested

Retenta has not executed this skill.

Security · not tested

The skill folder bundles no executable scripts. Retenta has not run a security scan.

Pinned publisher source: skills/web-perf/SKILL.md
Revision: c430dd965cea3a8faf0ef035e3b3d73b38518081
License evidence: Apache-2.0Retenta preserves the license text captured with this immutable upstream snapshot; no independent legal or security review is claimed.
Last source change: 2026-09-05
Independent verification: Published by Cloudflare, which does not own the product this skill covers. Not independently verified.
Upstream repository: Open publisher repository