/webperf

---
description: Run a web performance audit via the web-performance-auditor persona
---

`/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