When the BROWSE_EXTENSIONS_DIR environment variable is set to a path
containing an unpacked Chrome extension, browse launches Chromium in
headed mode with the window off-screen (simulating headless) and loads
the extension.
This enables use cases like ad blockers (reducing token waste from
ad-heavy pages), accessibility tools, and custom request header
management — all while maintaining the same CLI interface.
Implementation:
- Read BROWSE_EXTENSIONS_DIR env var in launch()
- When set: switch to headed mode with --window-position=-9999,-9999
(extensions require headed Chromium)
- Pass --load-extension and --disable-extensions-except to Chromium
- When unset: behavior is identical to before (headless, no extensions)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
