agent-browser-locale

name	agent-browser-locale
description	Test locale- and i18n-specific browser behavior with agent-browser by forcing a non-English JavaScript runtime locale through CDP. Use when reproducing or verifying bugs involving date/time markers, number or currency separators, Intl APIs, RTL behavior, or behavior that differs under locales such as sv-SE, tr-TR, zh-TW, de-DE, or ar-EG.

Test browser locale behavior

Use the installed agent-browser skill. Before running browser commands, load its current core guide with agent-browser skills get core.

agent-browser has no locale-emulation command. Chrome's --lang flag does not reliably change the JavaScript runtime locale on macOS. Use CDP Emulation.setLocaleOverride and keep the CDP session that applied it open for the entire test.

Set up an isolated browser

1. Resolve scripts/cdp-locale.mjs relative to this SKILL.md. Run it through its shebang; do not prefix it with node.
2. Create a task-specific Chrome profile with mktemp -d.
3. Launch Chrome headlessly with that exact profile and a dynamically assigned debugging port:

"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome" \
  --headless=new \
  --user-data-dir="$LOCALE_PROFILE_DIR" \
  --remote-debugging-port=0 \
  --no-first-run \
  --no-default-browser-check \
  about:blank

Run Chrome as an ongoing execution session and retain its execution-session ID. Do not background it with &. Wait for $LOCALE_PROFILE_DIR/DevToolsActivePort, then read the first line as the assigned port. If visible Chrome is genuinely necessary, launch it through an escalated execution request because it is a GUI action.

4. Generate a dedicated browser session name:

LOCALE_SESSION=$(agent-browser session id --scope cwd --prefix locale-test)

Pass --session "$LOCALE_SESSION" to every agent-browser command.

5. Start the helper as a second ongoing execution session and retain its execution-session ID:

/absolute/path/to/agent-browser-locale/scripts/cdp-locale.mjs sv-SE "$LOCALE_PORT"

The helper must print setLocaleOverride sv-SE: ok and remain running. If it exits, every later result is invalid.

6. Connect agent-browser to the same Chrome target:

agent-browser --session "$LOCALE_SESSION" connect "$LOCALE_PORT"
agent-browser --session "$LOCALE_SESSION" reload
agent-browser --session "$LOCALE_SESSION" eval "(1234.5).toLocaleString() + ' | ' + new Intl.DateTimeFormat().resolvedOptions().locale"

Expect the requested locale, such as 1 234,5 | sv-SE. If the result still reports en-US, stop. Do not report browser behavior gathered without a passing locale gate.

Drive and verify the page

Use the normal agent-browser snapshot and interaction loop, always with the dedicated session. Re-snapshot after navigation because refs become stale.

When proving a fix, compare the buggy and fixed builds under the same live locale. Confirm the buggy baseline reproduces before treating the fixed result as evidence. If a baseline is unavailable, retain the locale-gate output as the minimum validity evidence.

Useful stress locales include:

• sv-SE: Swedish em/fm
• tr-TR: Turkish ÖS/ÖÖ
• zh-TW: Chinese 下午/上午
• ar-EG: Arabic formatting and RTL behavior

The locale override survives navigation on the attached page while the helper remains connected. It does not automatically prove that a newly created page target inherited the override. Re-run the locale gate after opening a new tab or target.

Clean up safely

Stop only the two retained execution sessions. Never use pkill, process-name matching, or agent-browser close --all.

Close only the skill-owned browser session:

agent-browser --session "$LOCALE_SESSION" close

After Chrome has stopped, remove only the exact profile directory returned by this run's mktemp -d. Validate that the recorded path is non-empty, is not /, and is the task-created temporary directory before recursively removing it.

Failure rules

• If the helper dies or the locale gate changes to en-US, discard subsequent results.
• If Chrome or the helper hangs or fails, stop and report the captured error instead of retrying broad cleanup commands.
• Never use the user's real Chrome profile for locale testing.