# Firefox Agent Bridge

A small Firefox extension that exposes an **allowlisted** WebExtension API to local scripts and agents.

This is **not** a bookmark sync engine. Firefox already has `browser.bookmarks`. The extension is a bridge: while Firefox is open, a script on the same machine can call those functions over `http://127.0.0.1:17634`.

Agents: start at [AGENTS.md](AGENTS.md).

## Why this exists

Firefox will not let an outside process talk to Places. Editing `places.sqlite` while the browser is running loses deletes. The supported path is `browser.bookmarks` inside an extension, plus [native messaging](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Native_messaging) so a localhost HTTP host can reach that extension.

## Pieces

| Piece | Role |
|-------|------|
| `extension/` | WebExtension (`bookmarks` + `nativeMessaging`) |
| `host/` | Native host: stdio to Firefox, HTTP to scripts |
| `tools/client.py` | Signed Python caller (`FAB_KEY_FILE`) |
| `examples/replace_named_folder.py` | Sample "replace this folder" script |

## Install (this workstation)

1. Register the native host (once):

   ```powershell
   powershell -NoProfile -File tools\install-native-host.ps1
   ```

   That registers
   `HKCU\Software\Mozilla\NativeMessagingHosts\com.easygoingaming.firefox_agent_bridge`.

   Then create a client key **outside** that state directory and give the file to tooling:

   ```powershell
   python tools\register_client.py add --name cursor-agent --write-key $HOME\.fab\cursor-agent.json
   $env:FAB_KEY_FILE = "$HOME\.fab\cursor-agent.json"
   ```

2. Load the extension. Firefox Release will not keep an unsigned add-on across restarts:

   - `about:debugging#/runtime/this-firefox`
   - **Load Temporary Add-on**
   - pick `extension\manifest.json`

   Permanent install: Mozilla-signed `.xpi` — [docs/signing.md](docs/signing.md). Start with `--channel=unlisted`.

3. Leave Firefox open. The extension starts the host; `GET http://127.0.0.1:17634/health` should return JSON.

## Call it

```powershell
$env:FAB_KEY_FILE = "$HOME\.fab\cursor-agent.json"
python tools/client.py meta.methods
python tools/client.py bookmarks.search "[{\"title\":\"10.132.x.x\"}]"
```

See [AGENTS.md](AGENTS.md) for the method list, HTTP surface, and failure modes.

## Security

- Binds **127.0.0.1 only**. Browser `Origin` headers are rejected; `Host` must be loopback.
- Calls (except `/health`) must be signed by a **registered Ed25519 client**. The host keeps public keys only.
- Only the methods in `extension/background.js` `ALLOWED` run. No history, cookies, tabs, or `onMessageExternal` in v0.1.
- Another add-on with `bookmarks` already has Places; this bridge does not give it a new path in.

## License

MIT.