diff --git a/codex-rs/app-server/README.md b/codex-rs/app-server/README.md
index d96b0e514a..1585e1dc21 100644
--- a/codex-rs/app-server/README.md
+++ b/codex-rs/app-server/README.md
@@ -145,6 +145,7 @@ Example with notification opt-out:
 - `thread/start` — create a new thread; emits `thread/started` (including the current `thread.status`) and auto-subscribes you to turn/item events for that thread. When the request includes a `cwd` and the resolved sandbox is `workspace-write` or full access, app-server also marks that project as trusted in the user `config.toml`. Pass `sessionStartSource: "clear"` when starting a replacement thread after clearing the current session so `SessionStart` hooks receive `source: "clear"` instead of the default `"startup"`. For permissions, prefer `permissionProfile`; the legacy `sandbox` shorthand is still accepted but cannot be combined with `permissionProfile`. Experimental `environments` selects the sticky execution environments for turns on the thread; omit it to use the server default, pass `[]` to disable environments, or pass explicit environment ids with per-environment `cwd`.
 - `thread/resume` — reopen an existing thread by id so subsequent `turn/start` calls append to it. Accepts the same permission override rules as `thread/start`.
 - `thread/fork` — fork an existing thread into a new thread id by copying the stored history; if the source thread is currently mid-turn, the fork records the same interruption marker as `turn/interrupt` instead of inheriting an unmarked partial turn suffix. The returned `thread.forkedFromId` points at the source thread when known. Accepts `ephemeral: true` for an in-memory temporary fork, emits `thread/started` (including the current `thread.status`), and auto-subscribes you to turn/item events for the new thread. Pass `excludeTurns: true` when the client plans to page fork history via `thread/turns/list` instead of receiving the full turn array immediately. Accepts the same permission override rules as `thread/start`.
+- `thread/start`, `thread/resume`, and `thread/fork` responses include the legacy `sandbox` compatibility projection. Experimental clients can read response `permissionProfile` for the exact active runtime permissions and `activePermissionProfile` for the named profile identity/provenance when the permissions came from `default_permissions`.
 - `thread/list` — page through stored rollouts; supports cursor-based pagination and optional `modelProviders`, `sourceKinds`, `archived`, `cwd`, and `searchTerm` filters. Each returned `thread` includes `status` (`ThreadStatus`), defaulting to `notLoaded` when the thread is not currently loaded.
 - `thread/loaded/list` — list the thread ids currently loaded in memory.
 - `thread/read` — read a stored thread by id without resuming it; optionally include turns via `includeTurns`. The returned `thread` includes `status` (`ThreadStatus`), defaulting to `notLoaded` when the thread is not currently loaded.