# Image-owned Chromium runtime

TX9 installs Chrome for Testing and agent-browser under
`/opt/hermes-box/browser` during image build. Durable `/data` is not the
install location. Hermes still runs with `--skip-browser`. TX9 seeds a local
chrome engine only when no browser backend is already selected.

## Pins

Pins live in `box.env` and were measured on 2026-09-10.

- agent-browser 0.26.0
- Chrome for Testing 153.0.8010.36

`provision/install-browser.sh` selects linux-x64 or linux-arm64 from
`uname -m` and checks the matching sha256. An unknown machine type fails
the build. An amd64 artifact is never treated as arm64.

`install-browser.sh` skips the download when `manifest.json` matches the
current pins and both binaries pass the smoke check. OS libraries come from Chrome's own
`deb.deps` via `apt-get satisfy`, plus `unzip`, `libnss3-tools`, and Python with PyYAML. The
image does not run `npm install -g`, `vp install -g agent-browser`, or
`agent-browser install --with-deps`.

## Health

`tx9-browser health` returns the first failure.

- `ok`
- `cli_missing`
- `browser_missing`
- `libs_missing`
- `launch_failed`
- `navigate_failed`

Presence or `--version` is not enough. The probe runs image
`agent-browser --executable-path` against the local fixture and requires
the marker `TX9_BROWSER_FIXTURE_OK` in the accessibility snapshot.
`--dump-dom` is not the health signal. Chrome 153 never finishes that
command in Docker even when CDP is already up. `hb doctor` fails when the
result is not `ok`. HTTPS against example.com runs only when
`TX9_BROWSER_HTTPS_SMOKE=1`.

Probes use private sessions and temporary profiles. Cleanup targets only the
current invocation, so concurrent health checks cannot close each other's browser.
Config seeding parses YAML and atomically updates only the requested file,
retaining existing browser choices and unrelated settings.

`agent-browser` does not treat `$PATH/chrome` as a system install. The
image links `/usr/bin/google-chrome` and `/usr/bin/google-chrome-stable`
to `/opt/hermes-box/bin/chrome` so a plain `agent-browser open` finds it.

## Sandbox

The image does not set the SUID bit on `chrome_sandbox`. Hermes and
agent-browser may add `--no-sandbox --disable-dev-shm-usage` when user
namespaces cannot create a sandbox. TX9 does not export
`AGENT_BROWSER_ARGS` or `AGENT_BROWSER_EXECUTABLE_PATH`.

`~/.local` browser binaries stay. `hb doctor` may note when PATH hides
the image `agent-browser`.

## Upgrade and rollback

To upgrade, change the pins in `box.env`, rebuild the CLI with `make tx9`,
and rebuild the image. The CLI embeds the build context, so editing
`box.env` alone does not change `tx9 create`. To roll back, restore the
previous pins and rebuild the same way.

## What this does not fix

Repairing a live container's browser install is not product-ready. Hermes
`key_cmd` auth is out of scope.