# GUI Bridge Contract (`sdt bridge --stdio`)

The GUI uses a hybrid bridge:

- execution: `sdt run/debug --json` (streamed)
- read/manage: `sdt bridge --stdio` JSON-RPC over stdio

## Envelope

Request (one JSON object per line):

```json
{ "id": "req-1", "method": "workspace.get", "params": { "projectRoot": "E:\\repo" } }
```

Response:

```json
{ "id": "req-1", "ok": true, "result": { "...": "..." }, "error": null }
```

Error response:

```json
{
  "id": "req-1",
  "ok": false,
  "result": null,
  "error": { "code": "validation_failed", "message": "Missing required parameter 'filePath'." }
}
```

## Methods (v1)

- `workspace.get`
- `workspace.add` (`candidatePath`, `initializeConfig`)
- `favorites.list`
- `favorites.toggle` (`favoriteProjectPath`, `workflowId`, `label`)
- `history.list` (`limit`)
- `events.listFiles`
- `events.readFile` (`filePath`)
- `envProfiles.list`
- `envProfiles.resolve` (`envProfile`)
- `doctor.run`
- `setup.plan` (read-only preview)

## Determinism Notes

- Responses are always single-envelope JSON.
- Unknown methods return `method_not_found`.
- Parameter issues return `validation_failed`.
- GUI should tolerate additive fields in `result`.