app-server: Emit thread archive/unarchive notifications (#12030)

* Add v2 server notifications `thread/archived` and `thread/unarchived`
with a `threadId` payload.
* Wire new events into `thread/archive` and `thread/unarchive` success
paths.
* Update app-server protocol/schema/docs accordingly.

Testing:
- Updated archive/unarchive end-to-end tests to verify both
notifications are emitted with the expected thread id payload.

codex-rs/app-server/README.md

@@ -120,9 +120,9 @@ Example with notification opt-out:
 - `thread/list` — page through stored rollouts; supports cursor-based pagination and optional `modelProviders`, `sourceKinds`, `archived`, and `cwd` filters.
 - `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`.
-- `thread/archive` — move a thread’s rollout file into the archived directory; returns `{}` on success.
+- `thread/archive` — move a thread’s rollout file into the archived directory; returns `{}` on success and emits `thread/archived`.
 - `thread/name/set` — set or update a thread’s user-facing name; returns `{}` on success. Thread names are not required to be unique; name lookups resolve to the most recently updated thread.
-- `thread/unarchive` — move an archived rollout file back into the sessions directory; returns the restored `thread` on success.
+- `thread/unarchive` — move an archived rollout file back into the sessions directory; returns the restored `thread` on success and emits `thread/unarchived`.
 - `thread/compact/start` — trigger conversation history compaction for a thread; returns `{}` immediately while progress streams through standard turn/item notifications.
 - `thread/backgroundTerminals/clean` — terminate all running background terminals for a thread (experimental; requires `capabilities.experimentalApi`); returns `{}` when the cleanup request is accepted.
 - `thread/rollback` — drop the last N turns from the agent’s in-memory context and persist a rollback marker in the rollout so future resumes see the pruned history; returns the updated `thread` (with `turns` populated) on success.
@@ -274,6 +274,7 @@ Use `thread/archive` to move the persisted rollout (stored as a JSONL file on di
 ```json
 { "method": "thread/archive", "id": 21, "params": { "threadId": "thr_b" } }
 { "id": 21, "result": {} }
+{ "method": "thread/archived", "params": { "threadId": "thr_b" } }
 ```
 
 An archived thread will not appear in `thread/list` unless `archived` is set to `true`.
@@ -285,6 +286,7 @@ Use `thread/unarchive` to move an archived rollout back into the sessions direct
 ```json
 { "method": "thread/unarchive", "id": 24, "params": { "threadId": "thr_b" } }
 { "id": 24, "result": { "thread": { "id": "thr_b" } } }
+{ "method": "thread/unarchived", "params": { "threadId": "thr_b" } }
 ```
 
 ### Example: Trigger thread compaction
@@ -519,7 +521,7 @@ Notes:
 
 ## Events
 
-Event notifications are the server-initiated event stream for thread lifecycles, turn lifecycles, and the items within them. After you start or resume a thread, keep reading stdout for `thread/started`, `turn/*`, and `item/*` notifications.
+Event notifications are the server-initiated event stream for thread lifecycles, turn lifecycles, and the items within them. After you start or resume a thread, keep reading stdout for `thread/started`, `thread/archived`, `thread/unarchived`, `turn/*`, and `item/*` notifications.
 
 ### Notification opt-out
 

codex-rs/app-server/src/codex_message_processor.rs

@@ -122,6 +122,7 @@ use codex_app_server_protocol::SkillsRemoteWriteResponse;
 use codex_app_server_protocol::Thread;
 use codex_app_server_protocol::ThreadArchiveParams;
 use codex_app_server_protocol::ThreadArchiveResponse;
+use codex_app_server_protocol::ThreadArchivedNotification;
 use codex_app_server_protocol::ThreadBackgroundTerminalsCleanParams;
 use codex_app_server_protocol::ThreadBackgroundTerminalsCleanResponse;
 use codex_app_server_protocol::ThreadCompactStartParams;
@@ -147,6 +148,7 @@ use codex_app_server_protocol::ThreadStartResponse;
 use codex_app_server_protocol::ThreadStartedNotification;
 use codex_app_server_protocol::ThreadUnarchiveParams;
 use codex_app_server_protocol::ThreadUnarchiveResponse;
+use codex_app_server_protocol::ThreadUnarchivedNotification;
 use codex_app_server_protocol::Turn;
 use codex_app_server_protocol::TurnInterruptParams;
 use codex_app_server_protocol::TurnStartParams;
@@ -2126,10 +2128,17 @@ impl CodexMessageProcessor {
                 }
             };
 
+        let thread_id_str = thread_id.to_string();
         match self.archive_thread_common(thread_id, &rollout_path).await {
             Ok(()) => {
                 let response = ThreadArchiveResponse {};
                 self.outgoing.send_response(request_id, response).await;
+                let notification = ThreadArchivedNotification {
+                    thread_id: thread_id_str,
+                };
+                self.outgoing
+                    .send_server_notification(ServerNotification::ThreadArchived(notification))
+                    .await;
             }
             Err(err) => {
                 self.outgoing.send_error(request_id, err).await;
@@ -2335,8 +2344,13 @@ impl CodexMessageProcessor {
 
         match result {
             Ok(thread) => {
+                let thread_id = thread.id.clone();
                 let response = ThreadUnarchiveResponse { thread };
                 self.outgoing.send_response(request_id, response).await;
+                let notification = ThreadUnarchivedNotification { thread_id };
+                self.outgoing
+                    .send_server_notification(ServerNotification::ThreadUnarchived(notification))
+                    .await;
             }
             Err(err) => {
                 self.outgoing.send_error(request_id, err).await;

codex-rs/app-server/tests/suite/v2/thread_archive.rs

@@ -7,6 +7,7 @@ use codex_app_server_protocol::JSONRPCResponse;
 use codex_app_server_protocol::RequestId;
 use codex_app_server_protocol::ThreadArchiveParams;
 use codex_app_server_protocol::ThreadArchiveResponse;
+use codex_app_server_protocol::ThreadArchivedNotification;
 use codex_app_server_protocol::ThreadStartParams;
 use codex_app_server_protocol::ThreadStartResponse;
 use codex_app_server_protocol::TurnStartParams;
@@ -14,6 +15,7 @@ use codex_app_server_protocol::TurnStartResponse;
 use codex_app_server_protocol::UserInput;
 use codex_core::ARCHIVED_SESSIONS_SUBDIR;
 use codex_core::find_thread_path_by_id_str;
+use pretty_assertions::assert_eq;
 use std::path::Path;
 use tempfile::TempDir;
 use tokio::time::timeout;
@@ -122,6 +124,17 @@ async fn thread_archive_requires_materialized_rollout() -> Result<()> {
     )
     .await??;
     let _: ThreadArchiveResponse = to_response::<ThreadArchiveResponse>(archive_resp)?;
+    let archive_notification = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("thread/archived"),
+    )
+    .await??;
+    let archived_notification: ThreadArchivedNotification = serde_json::from_value(
+        archive_notification
+            .params
+            .expect("thread/archived notification params"),
+    )?;
+    assert_eq!(archived_notification.thread_id, thread.id);
 
     // Verify file moved.
     let archived_directory = codex_home.path().join(ARCHIVED_SESSIONS_SUBDIR);

codex-rs/app-server/tests/suite/v2/thread_unarchive.rs

@@ -10,11 +10,13 @@ use codex_app_server_protocol::ThreadStartParams;
 use codex_app_server_protocol::ThreadStartResponse;
 use codex_app_server_protocol::ThreadUnarchiveParams;
 use codex_app_server_protocol::ThreadUnarchiveResponse;
+use codex_app_server_protocol::ThreadUnarchivedNotification;
 use codex_app_server_protocol::TurnStartParams;
 use codex_app_server_protocol::TurnStartResponse;
 use codex_app_server_protocol::UserInput;
 use codex_core::find_archived_thread_path_by_id_str;
 use codex_core::find_thread_path_by_id_str;
+use pretty_assertions::assert_eq;
 use std::fs::FileTimes;
 use std::fs::OpenOptions;
 use std::path::Path;
@@ -120,6 +122,17 @@ async fn thread_unarchive_moves_rollout_back_into_sessions_directory() -> Result
     let ThreadUnarchiveResponse {
         thread: unarchived_thread,
     } = to_response::<ThreadUnarchiveResponse>(unarchive_resp)?;
+    let unarchive_notification = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("thread/unarchived"),
+    )
+    .await??;
+    let unarchived_notification: ThreadUnarchivedNotification = serde_json::from_value(
+        unarchive_notification
+            .params
+            .expect("thread/unarchived notification params"),
+    )?;
+    assert_eq!(unarchived_notification.thread_id, thread.id);
     assert!(
         unarchived_thread.updated_at > old_timestamp,
         "expected updated_at to be bumped on unarchive"