chrome-devtools

Files (2)

• SKILL.md
• cli.md · references/

SKILL.md (first lines)

# Chrome DevTools

Use Chrome DevTools MCP or its CLI for live browser diagnostics. [playwright](../playwright/SKILL.md) owns repeatable end-to-end journeys; [web-frontend](../web-frontend/SKILL.md) owns platform implementation guidance.

## Setup

Require Node.js LTS, `npm`/`npx`, and supported Chrome. Reuse an available DevTools connection; otherwise follow [mcp-setup](../mcp-setup/SKILL.md) for the active harness. The launch command below uses a reviewed package pin; recheck installed help before updating it.

```bash
npx --yes chrome-devtools-mcp@1.12.0 --isolated --headless --no-usage-statistics --no-performance-crux
```

The MCP client starts that process over stdio. Use a dedicated browser profile. Keep remote debugging on loopback; browser content, network bodies, cookies, screenshots, and traces may expose private data. The two opt-out flags disable MCP usage statistics and CrUX URL lookups respectively.

## Task guides

<!-- guides:start -->

- [cli](references/cli.md): Drive DevTools from the shell with the chrome-devtools CLI daemon instead of an MCP connection.

<!-- guides:end -->

## Workflow

1. **Identify the target**: list pages and select the intended page ID, URL, viewport, and browser mode. Take a fresh accessibility snapshot before using element UIDs; navigation and rerenders can invalidate them.
1. **Reproduce the symptom**: list bounded console errors and failed-request metadata, then inspect only the relevant request IDs and bodies. Reuse a still-current snapshot; refresh it after navigation or a relevant rerender. Save large traces as artifacts instead of returning their raw contents. Redact credentials and private request data.
1. **Measure performance**: record a bounded trace of the same action before and after a change; preserve CPU/network throttling, cache conditions, viewport, and tool versions. Stop traces you started and save artifacts in the authorized workspace.
1. **Check accessibility**: inspect roles, names, focus order, keyboard operation, and visible contrast. Run `lighthouse_audit` for the one-shot accessibility, SEO, and best-practice report; it reloads the page unless `mode` is `snapshot`, and it excludes performance, which needs a trace. Combine automated checks with manual interaction; an accessibility tree or Lighthouse score alone does not establish WCAG conformance.
1. **Investigate memory and cookies**: compare repeated lifecycle actions and heap snapshots; `take_heapsnapshot` is on by default, while `compare_heapsnapshots` and the other analysis tools need `--memoryDebugging` on the MCP server; inspect `HttpOnly`, `Secure`, `SameSite`, and partitioning in the request's actual context. A single heap size or cookie attribute is not a diagnosis.
1. **Close task-owned pages**: after verifying the fix.

## Gotchas

- **Pin the browser mode**: set headed or headless explicitly for reproducibility; the CLI defaults to headless, which need not match a separately configured MCP connection.

## Official Skills

Upstream: [ChromeDevTools/chrome-devtools-mcp skills](https://github.com/ChromeDevTools/chrome-devtools-mcp/tree/main/skills). Use `DISABLE_TELEMETRY=1 skills add ChromeDevTools/chrome-devtools-mcp --list`, then follow the shared [vendor-skill policy](../agent-project/references/vendor-skills.md) for the required guidance. Select task-specific entries such as `a11y-debugging` or `memory-leak-debugging`; preview the same-name `chrome-devtools` entry (also in `github/awesome-copilot`) instead of installing it ([vendor-skill policy](../agent-project/references/vendor-skills.md#name-collisions)).

## Documentation

- [Chrome DevTools for agents](https://github.com/ChromeDevTools/chrome-devtools-mcp) · [Tool reference](https://github.com/ChromeDevTools/chrome-devtools-mcp/blob/main/docs/tool-reference.md)
- Releases: [chrome-devtools-mcp](https://github.com/ChromeDevTools/chrome-devtools-mcp/releases)
- Companion skills: [mcp-setup](../mcp-setup/SKILL.md), [playwright](../playwright/SKILL.md), [web-frontend](../web-frontend/SKILL.md), [benchmark](../systematic-debugging/references/benchmark.md), [quality-assurance](../quality-assurance/SKILL.md).

From fmind/dot, MIT.

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