A command for auditing the performance of web applications, meaning software that runs in a browser. It can use reports or live browser measurements, or inspect source code when those measurements are unavailable.

Auditing a site with Lighthouse, PageSpeed Insights, Chrome DevTools, or CrUX data, and scanning web-app source code for performance anti-patterns.

It helps identify browser-facing slowdowns and structural problems that can make pages load or respond slowly.

webperf — Command for Claude Code by ishandutta2007

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.

Clone the repo

git clone --depth 1 https://github.com/ishandutta2007/Awesome-Agent-Skills

Made for: Claude Code.

Or install agent-skills, the plugin that ships this one along with the rest of its 31 skills, 9 commands, 4 agents.

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.

README.md

[![agentmods](https://agentmods.dev/badge/commands/ishandutta2007/awesome-agent-skills/webperf/github.svg)](https://agentmods.dev/commands/ishandutta2007/awesome-agent-skills/webperf)

Your own site

<a href="https://agentmods.dev/commands/ishandutta2007/awesome-agent-skills/webperf"><img src="https://agentmods.dev/badge/commands/ishandutta2007/awesome-agent-skills/webperf/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.

Your own site · 80×15

<a href="https://agentmods.dev/commands/ishandutta2007/awesome-agent-skills/webperf"><img src="https://agentmods.dev/badge/commands/ishandutta2007/awesome-agent-skills/webperf.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 13 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 448 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 100% copy Near-identical to another mod 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.

Model	Per session	Once invoked
Fable 5.1	$0.00013	$0.00448
Opus 5.5	$0.00005	$0.00179
Sonnet 5.5	$0.00003	$0.00090
Haiku 4.5	$0.00001	$0.00045

Measured 1mo ago against content hash 74c0c1335f13, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

webperf 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 1mo 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.

Origin

This is a copy

100% identical to webperf — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/commands/webperf.md · 33 lines

What it actually says

/webperf targets web applications specifically. Do not use it for utility libraries, CLIs, or server-only code with no browser-facing output.

Determine the mode

Deep mode — activate when any of these is available:

A Lighthouse JSON report file (e.g. npx lighthouse <url> --output json --output-path ./report.json, or npx -p chrome-devtools-mcp chrome-devtools lighthouse_audit --output-format=json from the Chrome DevTools MCP CLI)
A PageSpeed Insights JSON response (includes Lighthouse + CrUX)
A CrUX API response (requires CRUX_API_KEY or GOOGLE_API_KEY)
A DevTools performance trace
A live URL plus the chrome-devtools MCP server configured in the harness (the agent can capture metrics directly via lighthouse_audit and performance_* tools)
The Chrome DevTools MCP CLI invoked locally (via npx -p chrome-devtools-mcp chrome-devtools <tool> or after npm i -g chrome-devtools-mcp) — the user runs commands like chrome-devtools lighthouse_audit --output-format=json and passes the JSON output to the agent

Quick mode — default when none of the above are available. The agent scans source code for structural anti-patterns and labels every finding as potential impact.

Run the audit

Spawn the web-performance-auditor subagent. Pass it explicitly:

The files, components, or diff under review
Any artifact paths (Lighthouse JSON, PSI JSON, CrUX response, trace) or pasted JSON content
The target URL or page name when known
A note on which mode you expect (Quick or Deep), so the agent surfaces missing inputs if Deep was intended

The subagent returns a scorecard (only populated with sourced values), a ranked list of findings, positive observations, and proactive recommendations.

Output

Return the full audit report to the user. No synthesis or merge step is needed — this is a single-persona command.

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.

1mo ago First seen · 33 lines · 13 tokens per session scan A 74c0c1335f13

Subscribe to this mod's changes

webperf is a command published in the GitHub repository ishandutta2007/Awesome-Agent-Skills (21 stars, last pushed 2mo ago), licensed MIT. It adds 13 tokens to every session and 448 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to webperf, differing in 0 lines, and is treated as a copy.

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