pagespeed-insights-read

pagespeed-insights-read is a skill for Claude Code, Codex from Considus/pagespeed-insights-mcp. It costs 114 tokens per session (2,757 once invoked), scanned A, original, Apache-2.0.

Guidance for interpreting results from the PageSpeed Insights MCP server, which measures website speed and user experience. It explains how to account for variation between repeated measurements.

In plain words
What is it for?
Answering questions about Lighthouse scores, Core Web Vitals, loading phases, estimated savings, and whether a page-speed change is measurable.
Why use it?
A single speed score or estimated saving can change even when the page has not changed. This prevents treating normal measurement noise as a real improvement.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code.

Good fit Answering questions about Lighthouse scores, Core Web Vitals, loading phases, estimated savings, and whether a page-speed change is measurable.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/considus/pagespeed-insights-mcp/pagespeed-insights-read
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 Considus/pagespeed-insights-mcp --skill pagespeed-insights-read
Clone the repo
git clone --depth 1 https://github.com/Considus/pagespeed-insights-mcp

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 pagespeed-insights-read

README.md
[![agentmods](https://agentmods.dev/badge/skills/considus/pagespeed-insights-mcp/pagespeed-insights-read/github.svg)](https://agentmods.dev/skills/considus/pagespeed-insights-mcp/pagespeed-insights-read)
Your own site
<a href="https://agentmods.dev/skills/considus/pagespeed-insights-mcp/pagespeed-insights-read"><img src="https://agentmods.dev/badge/skills/considus/pagespeed-insights-mcp/pagespeed-insights-read/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 pagespeed-insights-read

Your own site · 80×15
<a href="https://agentmods.dev/skills/considus/pagespeed-insights-mcp/pagespeed-insights-read"><img src="https://agentmods.dev/badge/skills/considus/pagespeed-insights-mcp/pagespeed-insights-read.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 114 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,757 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 $0.00114 $0.02757
Opus 5 $0.00057 $0.01378
Sonnet 5 $0.00023 $0.00551
Haiku 4.5 $0.00011 $0.00276

Measured 11d ago against content hash 070613189150, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

pagespeed-insights-read 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 11d ago.

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.

skills/pagespeed-insights-read/SKILL.md · 237 lines

How it starts

The opening of the file, as written. The whole thing — 237 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Reading PageSpeed results

The MCP server refuses to state a number without its uncertainty. It cannot stop an assistant discarding that uncertainty on the way to an answer, which is the failure this skill exists to prevent.

Every rule below came from measuring, and the measurements are quoted so they can be checked rather than believed.

The one that matters most: a change smaller than the spread is not a change

Every score and metric comes back as a median with the range across distinct analyses. That range is the instrument moving on a page that did not change.

Measured on one unchanged page: performance ran 27 to 37 across three analyses, Total Blocking Time 824ms to 3.05s, and estimated savings for one fix ranged 1450 to 2750ms.

So:

  • Do not report "performance improved from 33 to 36". That is inside the noise.
  • Do not compare today's median against yesterday's median without both spreads. Two medians that differ by less than the ranges overlap tell you nothing.
  • If asked whether something got better, say what the spreads were and whether they overlap. If they overlap, the honest answer is "no measurable change", not a hedged yes.

Use compare rather than doing this arithmetic yourself. It holds the baseline, applies the overlap rule, and will refuse a verdict where you might not.

Never add savings together

Findings carry Google's estimate of what each fix returns, per metric. These do not compose. Two fixes claiming 6750ms and 1200ms off LCP do not return 7950ms. They overlap, and Lighthouse models no interaction between them.

  • Never sum them into a total.
  • Never promise a resulting score. There is no way to get from a saving to a score, because the curve is not linear.
  • The ordering is the useful part. Say "fix this first", not "this will save you nine seconds".

The LCP phases do not add up to the LCP

explain_lcp returns four phases. They are each a separate 75th percentile, so they do not sum to the LCP and are not meant to. Measured across twelve real origins, the sum missed every time and in both directions, from 40ms under to 2616ms over.

Read the full file on GitHub · 237 lines

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. 11d ago First seen · 237 lines · 114 tokens per session scan A 070613189150

Subscribe to this mod's changes

pagespeed-insights-read is a skill published in the GitHub repository Considus/pagespeed-insights-mcp (0 stars, last pushed 11d ago), licensed Apache-2.0. It adds 114 tokens to every session and 2,757 once invoked, about $0.0006 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 2026-08-31.

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