[codex-analytics] thread events (#15690)

- add event for thread initialization
- thread/start, thread/fork, thread/resume
- feature flagged behind `FeatureFlag::GeneralAnalytics`
- does not yet support threads started by subagents

PR stack:
- --> [[telemetry] thread events
#15690](https://github.com/openai/codex/pull/15690)
- [[telemetry] subagent events
#15915](https://github.com/openai/codex/pull/15915)
- [[telemetry] turn events
#15591](https://github.com/openai/codex/pull/15591)
- [[telemetry] steer events
#15697](https://github.com/openai/codex/pull/15697)
- [[telemetry] queued prompt data
#15804](https://github.com/openai/codex/pull/15804)


Sample extracted logs in Codex-backend
```
INFO     | 2026-03-29 16:39:37 | codex_backend.routers.analytics_events | analytics_events.track_analytics_events:398 | Tracked analytics event codex_thread_initialized thread_id=019d3bf7-9f5f-7f82-9877-6d48d1052531 product_surface=codex product_client_id=CODEX_CLI client_name=codex-tui client_version=0.0.0 rpc_transport=in_process experimental_api_enabled=True codex_rs_version=0.0.0 runtime_os=macos runtime_os_version=26.4.0 runtime_arch=aarch64 model=gpt-5.3-codex ephemeral=False thread_source=user initialization_mode=new subagent_source=None parent_thread_id=None created_at=1774827577 | 
INFO     | 2026-03-29 16:45:46 | codex_backend.routers.analytics_events | analytics_events.track_analytics_events:398 | Tracked analytics event codex_thread_initialized thread_id=019d3b84-5731-79d0-9b3b-9c6efe5f5066 product_surface=codex product_client_id=CODEX_CLI client_name=codex-tui client_version=0.0.0 rpc_transport=in_process experimental_api_enabled=True codex_rs_version=0.0.0 runtime_os=macos runtime_os_version=26.4.0 runtime_arch=aarch64 model=gpt-5.3-codex ephemeral=False thread_source=user initialization_mode=resumed subagent_source=None parent_thread_id=None created_at=1774820022 | 
INFO     | 2026-03-29 16:45:49 | codex_backend.routers.analytics_events | analytics_events.track_analytics_events:398 | Tracked analytics event codex_thread_initialized thread_id=019d3bfd-4cd6-7c12-a13e-48cef02e8c4d product_surface=codex product_client_id=CODEX_CLI client_name=codex-tui client_version=0.0.0 rpc_transport=in_process experimental_api_enabled=True codex_rs_version=0.0.0 runtime_os=macos runtime_os_version=26.4.0 runtime_arch=aarch64 model=gpt-5.3-codex ephemeral=False thread_source=user initialization_mode=forked subagent_source=None parent_thread_id=None created_at=1774827949 | 
INFO     | 2026-03-29 17:20:29 | codex_backend.routers.analytics_events | analytics_events.track_analytics_events:398 | Tracked analytics event codex_thread_initialized thread_id=019d3c1d-0412-7ed2-ad24-c9c0881a36b0 product_surface=codex product_client_id=CODEX_SERVICE_EXEC client_name=codex_exec client_version=0.0.0 rpc_transport=in_process experimental_api_enabled=True codex_rs_version=0.0.0 runtime_os=macos runtime_os_version=26.4.0 runtime_arch=aarch64 model=gpt-5.3-codex ephemeral=False thread_source=user initialization_mode=new subagent_source=None parent_thread_id=None created_at=1774830027 | 
```

Notes
- `product_client_id` gets canonicalized in codex-backend
- subagent threads are addressed in a following pr

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

@@ -32,6 +32,7 @@ use codex_app_server_protocol::CancelLoginAccountParams;
 use codex_app_server_protocol::CancelLoginAccountResponse;
 use codex_app_server_protocol::CancelLoginAccountStatus;
 use codex_app_server_protocol::ClientRequest;
+use codex_app_server_protocol::ClientResponse;
 use codex_app_server_protocol::CodexErrorInfo as AppServerCodexErrorInfo;
 use codex_app_server_protocol::CollaborationModeListParams;
 use codex_app_server_protocol::CollaborationModeListResponse;
@@ -179,6 +180,7 @@ use codex_arg0::Arg0DispatchPaths;
 use codex_backend_client::Client as BackendClient;
 use codex_chatgpt::connectors;
 use codex_cloud_requirements::cloud_requirements_loader;
+use codex_core::AnalyticsEventsClient;
 use codex_core::AuthManager;
 use codex_core::CodexAuth;
 use codex_core::CodexThread;
@@ -403,6 +405,7 @@ pub(crate) struct CodexMessageProcessor {
     auth_manager: Arc<AuthManager>,
     thread_manager: Arc<ThreadManager>,
     outgoing: Arc<OutgoingMessageSender>,
+    analytics_events_client: AnalyticsEventsClient,
     arg0_paths: Arg0DispatchPaths,
     config: Arc<Config>,
     cli_overrides: Arc<RwLock<Vec<(String, TomlValue)>>>,
@@ -433,6 +436,8 @@ struct ListenerTaskContext {
     thread_manager: Arc<ThreadManager>,
     thread_state_manager: ThreadStateManager,
     outgoing: Arc<OutgoingMessageSender>,
+    analytics_events_client: AnalyticsEventsClient,
+    general_analytics_enabled: bool,
     thread_watch_manager: ThreadWatchManager,
     fallback_model_provider: String,
     codex_home: PathBuf,
@@ -455,6 +460,7 @@ pub(crate) struct CodexMessageProcessorArgs {
     pub(crate) auth_manager: Arc<AuthManager>,
     pub(crate) thread_manager: Arc<ThreadManager>,
     pub(crate) outgoing: Arc<OutgoingMessageSender>,
+    pub(crate) analytics_events_client: AnalyticsEventsClient,
     pub(crate) arg0_paths: Arg0DispatchPaths,
     pub(crate) config: Arc<Config>,
     pub(crate) cli_overrides: Arc<RwLock<Vec<(String, TomlValue)>>>,
@@ -519,6 +525,7 @@ impl CodexMessageProcessor {
             auth_manager,
             thread_manager,
             outgoing,
+            analytics_events_client,
             arg0_paths,
             config,
             cli_overrides,
@@ -531,6 +538,7 @@ impl CodexMessageProcessor {
             auth_manager,
             thread_manager,
             outgoing: outgoing.clone(),
+            analytics_events_client,
             arg0_paths,
             config,
             cli_overrides,
@@ -2086,6 +2094,8 @@ impl CodexMessageProcessor {
             thread_manager: Arc::clone(&self.thread_manager),
             thread_state_manager: self.thread_state_manager.clone(),
             outgoing: Arc::clone(&self.outgoing),
+            analytics_events_client: self.analytics_events_client.clone(),
+            general_analytics_enabled: self.config.features.enabled(Feature::GeneralAnalytics),
             thread_watch_manager: self.thread_watch_manager.clone(),
             fallback_model_provider: self.config.model_provider_id.clone(),
             codex_home: self.config.codex_home.clone(),
@@ -2318,6 +2328,17 @@ impl CodexMessageProcessor {
                     sandbox: config_snapshot.sandbox_policy.into(),
                     reasoning_effort: config_snapshot.reasoning_effort,
                 };
+                if listener_task_context.general_analytics_enabled {
+                    listener_task_context
+                        .analytics_events_client
+                        .track_response(
+                            request_id.connection_id.0,
+                            ClientResponse::ThreadStart {
+                                request_id: request_id.request_id.clone(),
+                                response: response.clone(),
+                            },
+                        );
+                }
 
                 listener_task_context
                     .outgoing
@@ -3796,6 +3817,15 @@ impl CodexMessageProcessor {
                     sandbox: session_configured.sandbox_policy.into(),
                     reasoning_effort: session_configured.reasoning_effort,
                 };
+                if self.config.features.enabled(Feature::GeneralAnalytics) {
+                    self.analytics_events_client.track_response(
+                        request_id.connection_id.0,
+                        ClientResponse::ThreadResume {
+                            request_id: request_id.request_id.clone(),
+                            response: response.clone(),
+                        },
+                    );
+                }
 
                 self.outgoing.send_response(request_id, response).await;
             }
@@ -4403,6 +4433,15 @@ impl CodexMessageProcessor {
             sandbox: session_configured.sandbox_policy.into(),
             reasoning_effort: session_configured.reasoning_effort,
         };
+        if self.config.features.enabled(Feature::GeneralAnalytics) {
+            self.analytics_events_client.track_response(
+                request_id.connection_id.0,
+                ClientResponse::ThreadFork {
+                    request_id: request_id.request_id.clone(),
+                    response: response.clone(),
+                },
+            );
+        }
 
         self.outgoing.send_response(request_id, response).await;
 
@@ -6984,6 +7023,8 @@ impl CodexMessageProcessor {
                 thread_manager: Arc::clone(&self.thread_manager),
                 thread_state_manager: self.thread_state_manager.clone(),
                 outgoing: Arc::clone(&self.outgoing),
+                analytics_events_client: self.analytics_events_client.clone(),
+                general_analytics_enabled: self.config.features.enabled(Feature::GeneralAnalytics),
                 thread_watch_manager: self.thread_watch_manager.clone(),
                 fallback_model_provider: self.config.model_provider_id.clone(),
                 codex_home: self.config.codex_home.clone(),
@@ -7071,6 +7112,8 @@ impl CodexMessageProcessor {
                 thread_manager: Arc::clone(&self.thread_manager),
                 thread_state_manager: self.thread_state_manager.clone(),
                 outgoing: Arc::clone(&self.outgoing),
+                analytics_events_client: self.analytics_events_client.clone(),
+                general_analytics_enabled: self.config.features.enabled(Feature::GeneralAnalytics),
                 thread_watch_manager: self.thread_watch_manager.clone(),
                 fallback_model_provider: self.config.model_provider_id.clone(),
                 codex_home: self.config.codex_home.clone(),
@@ -7102,6 +7145,8 @@ impl CodexMessageProcessor {
             outgoing,
             thread_manager,
             thread_state_manager,
+            analytics_events_client: _,
+            general_analytics_enabled: _,
             thread_watch_manager,
             fallback_model_provider,
             codex_home,

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

@@ -74,6 +74,7 @@ use codex_app_server_protocol::Result;
 use codex_app_server_protocol::ServerNotification;
 use codex_app_server_protocol::ServerRequest;
 use codex_arg0::Arg0DispatchPaths;
+use codex_core::AppServerRpcTransport;
 use codex_core::config::Config;
 use codex_core::config_loader::CloudRequirementsLoader;
 use codex_core::config_loader::LoaderOverrides;
@@ -393,6 +394,7 @@ fn start_uninitialized(args: InProcessStartArgs) -> InProcessClientHandle {
                 config_warnings: args.config_warnings,
                 session_source: args.session_source,
                 enable_codex_api_key_env: args.enable_codex_api_key_env,
+                rpc_transport: AppServerRpcTransport::InProcess,
             });
             let mut thread_created_rx = processor.thread_created_receiver();
             let mut session = ConnectionSessionState::default();

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

@@ -36,6 +36,7 @@ use codex_app_server_protocol::ConfigWarningNotification;
 use codex_app_server_protocol::JSONRPCMessage;
 use codex_app_server_protocol::TextPosition as AppTextPosition;
 use codex_app_server_protocol::TextRange as AppTextRange;
+use codex_core::AppServerRpcTransport;
 use codex_core::ExecPolicyError;
 use codex_core::check_execpolicy_for_warnings;
 use codex_core::config_loader::ConfigLoadError;
@@ -623,6 +624,7 @@ pub async fn run_main_with_transport(
             config_warnings,
             session_source,
             enable_codex_api_key_env: false,
+            rpc_transport: analytics_rpc_transport(transport),
         });
         let mut thread_created_rx = processor.thread_created_receiver();
         let mut running_turn_count_rx = processor.subscribe_running_assistant_turn_count();
@@ -846,6 +848,13 @@ pub async fn run_main_with_transport(
     Ok(())
 }
 
+fn analytics_rpc_transport(transport: AppServerTransport) -> AppServerRpcTransport {
+    match transport {
+        AppServerTransport::Stdio => AppServerRpcTransport::Stdio,
+        AppServerTransport::WebSocket { .. } => AppServerRpcTransport::Websocket,
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::LogFormat;

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

@@ -56,6 +56,7 @@ use codex_app_server_protocol::experimental_required_message;
 use codex_arg0::Arg0DispatchPaths;
 use codex_chatgpt::connectors;
 use codex_core::AnalyticsEventsClient;
+use codex_core::AppServerRpcTransport;
 use codex_core::AuthManager;
 use codex_core::ThreadManager;
 use codex_core::config::Config;
@@ -159,9 +160,11 @@ pub(crate) struct MessageProcessor {
     external_agent_config_api: ExternalAgentConfigApi,
     fs_api: FsApi,
     auth_manager: Arc<AuthManager>,
+    analytics_events_client: AnalyticsEventsClient,
     fs_watch_manager: FsWatchManager,
     config: Arc<Config>,
     config_warnings: Arc<Vec<ConfigWarningNotification>>,
+    rpc_transport: AppServerRpcTransport,
 }
 
 #[derive(Clone, Debug, Default)]
@@ -186,6 +189,7 @@ pub(crate) struct MessageProcessorArgs {
     pub(crate) config_warnings: Vec<ConfigWarningNotification>,
     pub(crate) session_source: SessionSource,
     pub(crate) enable_codex_api_key_env: bool,
+    pub(crate) rpc_transport: AppServerRpcTransport,
 }
 
 impl MessageProcessor {
@@ -205,6 +209,7 @@ impl MessageProcessor {
             config_warnings,
             session_source,
             enable_codex_api_key_env,
+            rpc_transport,
         } = args;
         let auth_manager = AuthManager::shared_with_external_chatgpt_auth_refresher(
             config.codex_home.clone(),
@@ -242,6 +247,7 @@ impl MessageProcessor {
             auth_manager: auth_manager.clone(),
             thread_manager: Arc::clone(&thread_manager),
             outgoing: outgoing.clone(),
+            analytics_events_client: analytics_events_client.clone(),
             arg0_paths,
             config: Arc::clone(&config),
             cli_overrides: cli_overrides.clone(),
@@ -262,7 +268,7 @@ impl MessageProcessor {
             loader_overrides,
             cloud_requirements,
             thread_manager,
-            analytics_events_client,
+            analytics_events_client.clone(),
         );
         let external_agent_config_api = ExternalAgentConfigApi::new(config.codex_home.clone());
         let fs_api = FsApi::default();
@@ -275,9 +281,11 @@ impl MessageProcessor {
             external_agent_config_api,
             fs_api,
             auth_manager,
+            analytics_events_client,
             fs_watch_manager,
             config,
             config_warnings: Arc::new(config_warnings),
+            rpc_transport,
         }
     }
 
@@ -547,6 +555,7 @@ impl MessageProcessor {
                 // shared thread when another connected client did not opt into
                 // experimental API). Proposed direction is instance-global first-write-wins
                 // with initialize-time mismatch rejection.
+                let analytics_initialize_params = params.clone();
                 let (experimental_api_enabled, opt_out_notification_methods) =
                     match params.capabilities {
                         Some(capabilities) => (
@@ -568,7 +577,7 @@ impl MessageProcessor {
                 session.app_server_client_name = Some(name.clone());
                 session.client_version = Some(version.clone());
                 let originator = name.clone();
-                if let Err(error) = set_default_originator(originator) {
+                if let Err(error) = set_default_originator(originator.clone()) {
                     match error {
                         SetOriginatorError::InvalidHeaderValue => {
                             let error = JSONRPCErrorError {
@@ -591,6 +600,14 @@ impl MessageProcessor {
                         }
                     }
                 }
+                if self.config.features.enabled(Feature::GeneralAnalytics) {
+                    self.analytics_events_client.track_initialize(
+                        connection_id.0,
+                        analytics_initialize_params,
+                        originator,
+                        self.rpc_transport,
+                    );
+                }
                 set_default_client_residency_requirement(self.config.enforce_residency.value());
                 let user_agent_suffix = format!("{name}; {version}");
                 if let Ok(mut suffix) = USER_AGENT_SUFFIX.lock() {

codex-rs/app-server/src/message_processor/tracing_tests.rs

@@ -20,6 +20,7 @@ use codex_app_server_protocol::TurnStartParams;
 use codex_app_server_protocol::TurnStartResponse;
 use codex_app_server_protocol::UserInput;
 use codex_arg0::Arg0DispatchPaths;
+use codex_core::AppServerRpcTransport;
 use codex_core::config::Config;
 use codex_core::config::ConfigBuilder;
 use codex_core::config_loader::CloudRequirementsLoader;
@@ -246,6 +247,7 @@ fn build_test_processor(
         config_warnings: Vec::new(),
         session_source: SessionSource::VSCode,
         enable_codex_api_key_env: false,
+        rpc_transport: AppServerRpcTransport::Stdio,
     });
     (processor, outgoing_rx)
 }