diff --git a/codex-rs/analytics/src/analytics_client.rs b/codex-rs/analytics/src/analytics_client.rs
index 1bccea915c..f42059a622 100644
--- a/codex-rs/analytics/src/analytics_client.rs
+++ b/codex-rs/analytics/src/analytics_client.rs
@@ -38,6 +38,23 @@ pub struct CodexThreadInitializedEvent {
     pub created_at: u64,
 }
 
+#[derive(Clone)]
+pub struct CodexThreadInitializedInput {
+    pub thread_id: String,
+    pub model: String,
+    pub created_at: u64,
+    pub thread_context: CodexThreadContext,
+}
+
+#[derive(Clone)]
+pub struct CodexThreadContext {
+    pub ephemeral: bool,
+    pub session_source: SessionSource,
+    pub initialization_mode: InitializationMode,
+    pub subagent_source: Option<SubAgentSource>,
+    pub parent_thread_id: Option<String>,
+}
+
 #[derive(Clone, Copy, Debug, Serialize)]
 #[serde(rename_all = "snake_case")]
 pub enum InitializationMode {
@@ -80,7 +97,7 @@ pub struct AppInvocation {
 }
 
 pub enum AnalyticsInput {
-    ThreadInitialized(ThreadInitializedInput),
+    ThreadInitialized(CodexThreadInitializedInput),
     SkillInvoked(SkillInvokedInput),
     AppMentioned(AppMentionedInput),
     AppUsed(AppUsedInput),
@@ -88,10 +105,6 @@ pub enum AnalyticsInput {
     PluginStateChanged(PluginStateChangedInput),
 }
 
-pub struct ThreadInitializedInput {
-    pub thread_event: CodexThreadInitializedEvent,
-}
-
 pub struct SkillInvokedInput {
     pub tracking: TrackEventsContext,
     pub invocations: Vec<SkillInvocation>,
@@ -228,10 +241,8 @@ impl AnalyticsEventsClient {
         }));
     }
 
-    pub fn track_thread_initialized(&self, thread_event: CodexThreadInitializedEvent) {
-        self.record(AnalyticsInput::ThreadInitialized(ThreadInitializedInput {
-            thread_event,
-        }));
+    pub fn track_thread_initialized(&self, input: CodexThreadInitializedInput) {
+        self.record(AnalyticsInput::ThreadInitialized(input));
     }
 
     pub fn track_app_mentioned(&self, tracking: TrackEventsContext, mentions: Vec<AppInvocation>) {
@@ -446,19 +457,29 @@ impl AnalyticsReducer {
 
     fn ingest_thread_initialized(
         &mut self,
-        input: ThreadInitializedInput,
+        input: CodexThreadInitializedInput,
         out: &mut Vec<TrackEventRequest>,
     ) {
+        let event = CodexThreadInitializedEvent {
+            thread_id: input.thread_id,
+            model: input.model,
+            ephemeral: input.thread_context.ephemeral,
+            session_source: input.thread_context.session_source,
+            initialization_mode: input.thread_context.initialization_mode,
+            subagent_source: input.thread_context.subagent_source,
+            parent_thread_id: input.thread_context.parent_thread_id,
+            created_at: input.created_at,
+        };
         self.threads.insert(
-            input.thread_event.thread_id.clone(),
+            event.thread_id.clone(),
             ThreadState {
-                _initialized_event: input.thread_event.clone(),
+                _initialized_event: event.clone(),
             },
         );
         out.push(TrackEventRequest::ThreadInitialized(
             CodexThreadInitializedEventRequest {
                 event_type: "codex_thread_initialized",
-                event_params: codex_thread_initialized_event_params(input.thread_event),
+                event_params: codex_thread_initialized_event_params(event),
             },
         ));
     }
diff --git a/codex-rs/analytics/src/lib.rs b/codex-rs/analytics/src/lib.rs
index 63455c0616..4ce20a0079 100644
--- a/codex-rs/analytics/src/lib.rs
+++ b/codex-rs/analytics/src/lib.rs
@@ -6,7 +6,9 @@ pub use analytics_client::AnalyticsReducer;
 pub use analytics_client::AppInvocation;
 pub use analytics_client::AppMentionedInput;
 pub use analytics_client::AppUsedInput;
+pub use analytics_client::CodexThreadContext;
 pub use analytics_client::CodexThreadInitializedEvent;
+pub use analytics_client::CodexThreadInitializedInput;
 pub use analytics_client::InitializationMode;
 pub use analytics_client::InvocationType;
 pub use analytics_client::PluginState;
@@ -14,6 +16,5 @@ pub use analytics_client::PluginStateChangedInput;
 pub use analytics_client::PluginUsedInput;
 pub use analytics_client::SkillInvocation;
 pub use analytics_client::SkillInvokedInput;
-pub use analytics_client::ThreadInitializedInput;
 pub use analytics_client::TrackEventsContext;
 pub use analytics_client::build_track_events_context;
diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index e3bf4049ff..d333ab7cc9 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -350,7 +350,8 @@ use crate::util::backoff;
 use crate::windows_sandbox::WindowsSandboxLevelExt;
 use codex_analytics::AnalyticsEventsClient;
 use codex_analytics::AppInvocation;
-use codex_analytics::CodexThreadInitializedEvent;
+use codex_analytics::CodexThreadContext;
+use codex_analytics::CodexThreadInitializedInput;
 use codex_analytics::InitializationMode;
 use codex_analytics::InvocationType;
 use codex_analytics::build_track_events_context;
@@ -670,23 +671,25 @@ impl Codex {
         session
             .services
             .analytics_events_client
-            .track_thread_initialized(CodexThreadInitializedEvent {
+            .track_thread_initialized(CodexThreadInitializedInput {
                 thread_id: thread_id.to_string(),
                 model: thread_initialized_configuration
                     .collaboration_mode
                     .model()
                     .to_string(),
-                ephemeral: thread_initialized_configuration
-                    .original_config_do_not_use
-                    .ephemeral,
-                initialization_mode,
-                subagent_source: session_source_subagent_source(&thread_session_source),
-                parent_thread_id: session_source_parent_thread_id(&thread_session_source),
-                session_source: thread_session_source,
                 created_at: SystemTime::now()
                     .duration_since(UNIX_EPOCH)
                     .unwrap_or_default()
                     .as_secs(),
+                thread_context: CodexThreadContext {
+                    ephemeral: thread_initialized_configuration
+                        .original_config_do_not_use
+                        .ephemeral,
+                    session_source: thread_session_source,
+                    initialization_mode,
+                    subagent_source: session_source_subagent_source(&thread_session_source),
+                    parent_thread_id: session_source_parent_thread_id(&thread_session_source),
+                },
             });
 
         // This task will run until Op::Shutdown is received.