Support renaming cloud threads (#61182)

## What changed

Handle `ThreadSetName` requests in the cloud backend through the cloud client's new `set_thread_name` method, without opening an attachment. Trim the requested name and reject empty names or thread IDs.

After the server acknowledges the rename, update the matching loaded thread's name and emit `ThreadNameUpdated`. Leave the cached name unchanged and emit no notification if the request fails.

## Testing

Add tests for the rename request payload, server acknowledgment and error handling, and preservation of the loaded thread's name when a rename fails.

GitOrigin-RevId: eecfe17a9cfba50c9fa9091a38a36c0011ab9246

codex-rs/app-server-client/src/cloud_backend/connection_tests.rs

@@ -8,9 +8,85 @@ use pretty_assertions::assert_eq;
 use wiremock::Mock;
 use wiremock::MockServer;
 use wiremock::ResponseTemplate;
+use wiremock::matchers::body_bytes;
 use wiremock::matchers::method;
 use wiremock::matchers::path;
 
+#[tokio::test]
+async fn rejected_rename_preserves_loaded_cloud_thread_name() -> Result<()> {
+    let server = MockServer::start().await;
+    let home = tempfile::tempdir()?;
+    let config = crate::legacy_core::config::ConfigBuilder::default()
+        .codex_home(home.path().to_owned())
+        .fallback_cwd(Some(home.path().to_owned()))
+        .without_project_context()
+        .build()
+        .await?;
+    let mut requests = requests::Requests {
+        client: std::sync::Arc::new(cloud::Client::new(
+            &config.http_client_factory(),
+            &server.uri(),
+            cloud::Credentials::new("synthetic-bearer", "synthetic-account")?,
+        )?),
+        account: protocol::GetAccountResponse {
+            user_id: None,
+            account: None,
+            requires_openai_auth: true,
+            workspace_routing: None,
+        },
+        loaded: Some(Box::new(serde_json::from_value(serde_json::json!({
+            "thread": {
+                "id": "t", "sessionId": "t", "preview": "", "ephemeral": false,
+                "modelProvider": "openai", "createdAt": 0, "updatedAt": 0,
+                "status": {"type": "idle"}, "cwd": home.path(), "cliVersion": "",
+                "source": "cli", "turns": [], "name": "Old",
+            },
+            "model": "test", "modelProvider": "openai", "cwd": home.path(),
+            "approvalPolicy": "never", "approvalsReviewer": "user",
+            "sandbox": {"type": "readOnly"},
+        }))?)),
+        warned_partial_history: None,
+    };
+    Mock::given(method("POST"))
+        .and(path(
+            "/oaiproto.codex_app_server_backend.ThreadService/SetThreadName",
+        ))
+        .and(body_bytes(b"\x00\x00\x00\x00\x08\x0a\x01t\x12\x03New"))
+        .respond_with(ResponseTemplate::new(503))
+        .expect(1)
+        .mount(&server)
+        .await;
+
+    let (output, mut notifications) = mpsc::unbounded_channel();
+    let mut replies = Replies::default();
+    let read = protocol::ThreadReadParams {
+        thread_id: "t".into(),
+        include_turns: false,
+    };
+    let rejected = handle_request(
+        protocol::ClientRequest::ThreadSetName {
+            request_id: protocol::RequestId::Integer(1),
+            params: protocol::ThreadSetNameParams {
+                thread_id: "t".into(),
+                name: " New ".into(),
+            },
+        },
+        cloud::SubmissionMode::StartIfIdle,
+        /*project*/ None,
+        &mut requests,
+        &mut replies,
+        &output,
+    )
+    .await;
+    assert!(rejected.unwrap_err().is::<cloud::MutationError>());
+    assert_eq!(
+        requests.read_thread(&read, /*status*/ None)?["thread"]["name"],
+        "Old"
+    );
+    assert!(notifications.try_recv().is_err());
+    Ok(())
+}
+
 #[tokio::test]
 async fn failed_archive_loaded_list_tracks_attachment_not_cached_metadata() -> Result<()> {
     let server = MockServer::start().await;

codex-rs/app-server-client/src/cloud_backend/requests.rs

@@ -72,6 +72,25 @@ impl Requests {
                 }
                 serde_json::to_value(page)?
             }
+            Request::ThreadSetName { params, .. } => {
+                let name = params.name.trim();
+                self.client.set_thread_name(&params.thread_id, name).await?;
+                if let Some(loaded) = &mut self.loaded
+                    && loaded.thread.id == params.thread_id
+                {
+                    loaded.thread.name = Some(name.to_owned());
+                }
+                send_notification(
+                    output,
+                    protocol::ServerNotification::ThreadNameUpdated(
+                        protocol::ThreadNameUpdatedNotification {
+                            thread_id: params.thread_id,
+                            thread_name: Some(name.to_owned()),
+                        },
+                    ),
+                );
+                serde_json::to_value(protocol::ThreadSetNameResponse {})?
+            }
             Request::ThreadArchive { params, .. } => {
                 self.client.archive_thread(&params.thread_id).await?;
                 return Ok(Response::Archived(params.thread_id));

codex-rs/cloud-client/src/client_tests.rs

@@ -132,6 +132,33 @@ async fn archive_addresses_the_requested_thread_and_requires_acknowledgment() {
     assert!(fixture.requests.try_recv().is_err());
 }
 
+#[tokio::test]
+async fn rename_sends_the_thread_and_title_and_requires_acknowledgment() {
+    let mut fixture = fixture_responses(vec![
+        response(vec![frame(&[])], tonic::Status::ok("")),
+        response(
+            vec![frame(&[])],
+            tonic::Status::permission_denied("synthetic denial"),
+        ),
+    ])
+    .await;
+
+    fixture.client.set_thread_name("t", "New").await.unwrap();
+    assert_request(&mut fixture, "SetThreadName", b"\x0a\x01t\x12\x03New").await;
+
+    let error = fixture
+        .client
+        .set_thread_name("u", "Other")
+        .await
+        .unwrap_err();
+    let MutationError::OutcomeUnknown(Error::Rpc(status)) = error else {
+        panic!("expected a remote rename failure");
+    };
+    assert_eq!(status.code, tonic::Code::PermissionDenied as i32);
+    assert_request(&mut fixture, "SetThreadName", b"\x0a\x01u\x12\x05Other").await;
+    assert!(fixture.requests.try_recv().is_err());
+}
+
 #[tokio::test]
 async fn activation_preserves_native_settings_and_thread_metadata() {
     // Native Thread fields encoded independently of the client's wire types.

codex-rs/cloud-client/src/lib.rs

@@ -298,6 +298,25 @@ impl Client {
         Ok(())
     }
 
+    /// Saves a conversation name without opening an attachment.
+    pub async fn set_thread_name(&self, thread_id: &str, name: &str) -> Result<(), MutationError> {
+        if thread_id.trim().is_empty() || name.trim().is_empty() {
+            return Err(MutationError::InvalidRequest);
+        }
+        let payload = self
+            .mutate(
+                wire::SetThreadNameRequest {
+                    thread_id: thread_id.to_owned(),
+                    name: name.to_owned(),
+                },
+                "/oaiproto.codex_app_server_backend.ThreadService/SetThreadName",
+            )
+            .await?;
+        wire::EmptyResponse::decode(payload)
+            .map_err(|_| MutationError::OutcomeUnknown(Error::InvalidResponse))?;
+        Ok(())
+    }
+
     /// Archives a conversation using the current account, without opening an attachment.
     pub async fn archive_thread(&self, thread_id: &str) -> Result<(), MutationError> {
         if thread_id.trim().is_empty() {

codex-rs/cloud-client/src/wire.rs

@@ -16,6 +16,14 @@ pub(crate) struct ThreadIdRequest {
     pub thread_id: String,
 }
 
+#[derive(Clone, prost::Message)]
+pub(crate) struct SetThreadNameRequest {
+    #[prost(string, tag = "1")]
+    pub thread_id: String,
+    #[prost(string, tag = "2")]
+    pub name: String,
+}
+
 #[derive(Clone, prost::Message)]
 pub(crate) struct UnarchiveResponse {
     #[prost(bytes = "bytes", optional, tag = "1")]