Nobrainer Browser

NoBrainer Browser

Use one Playwright-first browser path. The agent-focused @playwright/cli drives and inspects pages; the repository's Playwright test CLI records and opens traces. Do not add a second browser framework merely because one exists.

Route the task

Do not install MCP when the CLI covers the task. Do not install a browser plugin as the default path. Reuse an already configured MCP only when the current harness cannot run the CLI and the MCP has fresh capability readback.

Capability and install gate

First inspect the repository and machine:

command -v playwright-cli && playwright-cli --version
test -f package.json && npm exec playwright -- --version
npm view @playwright/cli dist-tags.latest --json

For interactive agent work, use the current npm channel only to discover a version, then pin that exact version for execution and record the readback:

PLAYWRIGHT_CLI_VERSION="$(npm view @playwright/cli version)"
test -n "$PLAYWRIGHT_CLI_VERSION"
npm install -g "@playwright/cli@$PLAYWRIGHT_CLI_VERSION"
playwright-cli --version
playwright-cli --help
playwright-cli --help attach

Package installation is a machine write. Perform it only when setup is within scope, and do not claim success until the binary readback passes. For a test repository, prefer its lockfile and package scripts over changing dependencies.

The CLI also offers playwright-cli install --skills. Do not run it by default while nobrainer-browser owns browser routing: that would add another skill owner with overlapping triggers. Read the live CLI help instead. If the owner chooses the upstream Playwright skills, reconcile to one browser-skill owner rather than keeping both active.

Restart an approved profile for CDP attach

Use this flow only when the owner explicitly approves closing the target browser and the target is an existing, dedicated Chromium user-data directory. It is not a way to make a daily/default Chrome profile remotely debuggable. Read the bounded CDP profile restart reference before any process or profile action; it separates identity readback, stopping, loopback launch, endpoint verification and CLI attach.

Existing-session attach

Use attach when the owner needs the actual approved session, login or open tab:

playwright-cli attach --cdp=chrome
playwright-cli attach --cdp=http://127.0.0.1:9222
# Example for a separately configured Edge debugging endpoint:
playwright-cli attach --cdp=http://127.0.0.1:9333

The current CLI accepts a supported channel such as chrome or an actual CDP endpoint URL; verify the live attach help because this interface can change. CDP attach is Chromium-only. Confirm the exact browser, profile, endpoint and write scope before acting. The CLI also exposes extension attach, but that is not the default because it requires a browser extension. If attach is unavailable, say so; do not bypass a saved browser permission block, copy or mirror a profile, extract cookies, reuse credentials, or silently launch a look-alike authenticated session. A request to inspect does not authorize form submission, purchase, publication, message sending, deletion or account changes.

If no existing login is required, a disposable session is simpler:

playwright-cli open https://example.com

Inspect and operate

Take a fresh snapshot before using element references, and refresh it after a navigation or substantial DOM change:

playwright-cli snapshot
playwright-cli find "Settings"
playwright-cli click e4
playwright-cli fill e7 "value"
playwright-cli eval "el => el.textContent" e4

Prefer semantic refs and visible state over brittle coordinates. For each material action, verify the resulting URL, visible state or downloaded artifact instead of trusting command exit alone.

Tests and traces

Use the repository's existing script/config first. Narrow the test target and record a trace when reproduction or evidence matters:

npx playwright test path/to/spec --trace on
REPORT_PORT=9324  # replace with an available explicit port
npx playwright show-report --port "$REPORT_PORT"
npx playwright show-trace trace.zip

For a live CLI flow:

playwright-cli tracing-start
playwright-cli snapshot
# perform the bounded steps
playwright-cli tracing-stop

Locate the actual trace artifact, preserve its path and open it. Review Actions, DOM snapshots, Network, Console and Source; a green status without the expected side effect is not proof. Use an available explicit report port; do not assume that --port 0 selects an ephemeral port across CLI versions. Treat traces as sensitive artifacts: they may contain cookies, headers, form values, URLs, payloads and private page content. Keep them in a project-ignored or temporary path, inspect and redact before sharing, and never commit them as routine evidence. Do not edit project trace policy merely to inspect one failure when a CLI flag is sufficient.

Failure and closeout

• If the CLI, target session or required permission is unavailable, stop with the exact failed probe and one remediation.
• If a trace cannot reproduce the issue, report NOT_REPRODUCED; do not invent a cause.
• For an attached external session use playwright-cli detach; never close it. Restart or close an existing profile only through the explicit pre-attach flow above. Close only a disposable session owned by this CLI run.
• Report the exact CLI version, browser/session mode, pages or tests inspected, trace/report paths, observed result, side effects, uncertainty and cleanup.

Sources: Playwright attach, Playwright connectOverCDP, Playwright test CLI, Trace Viewer, Chrome remote-debugging security changes, and @playwright/cli on npm.