progress

codex-rs/core/src/client.rs

@@ -58,6 +58,7 @@ pub struct ModelClient {
     config: Arc<Config>,
     auth_manager: Option<Arc<AuthManager>>,
     model_family: ModelFamily,
+    models_etag: Option<String>,
     otel_manager: OtelManager,
     provider: ModelProviderInfo,
     conversation_id: ConversationId,
@@ -72,6 +73,7 @@ impl ModelClient {
         config: Arc<Config>,
         auth_manager: Option<Arc<AuthManager>>,
         model_family: ModelFamily,
+        models_etag: Option<String>,
         otel_manager: OtelManager,
         provider: ModelProviderInfo,
         effort: Option<ReasoningEffortConfig>,
@@ -83,6 +85,7 @@ impl ModelClient {
             config,
             auth_manager,
             model_family,
+            models_etag,
             otel_manager,
             provider,
             conversation_id,
@@ -262,7 +265,7 @@ impl ModelClient {
                 store_override: None,
                 conversation_id: Some(conversation_id.clone()),
                 session_source: Some(session_source.clone()),
-                extra_headers: beta_feature_headers(&self.config),
+                extra_headers: beta_feature_headers(&self.config, self.models_etag.clone()),
             };
 
             let stream_result = client
@@ -398,7 +401,7 @@ fn build_api_prompt(prompt: &Prompt, instructions: String, tools_json: Vec<Value
     }
 }
 
-fn beta_feature_headers(config: &Config) -> ApiHeaderMap {
+fn beta_feature_headers(config: &Config, models_etag: Option<String>) -> ApiHeaderMap {
     let enabled = FEATURES
         .iter()
         .filter_map(|spec| {
@@ -416,6 +419,11 @@ fn beta_feature_headers(config: &Config) -> ApiHeaderMap {
     {
         headers.insert("x-codex-beta-features", header_value);
     }
+    if let Some(etag) = models_etag
+        && let Ok(header_value) = HeaderValue::from_str(&etag)
+    {
+        headers.insert("X-If-Models-Match", header_value);
+    }
     headers
 }
 

codex-rs/core/src/codex.rs

@@ -492,6 +492,7 @@ impl Session {
         session_configuration: &SessionConfiguration,
         per_turn_config: Config,
         model_family: ModelFamily,
+        models_etag: Option<String>,
         conversation_id: ConversationId,
         sub_id: String,
     ) -> TurnContext {
@@ -505,6 +506,7 @@ impl Session {
             per_turn_config.clone(),
             auth_manager,
             model_family.clone(),
+            models_etag,
             otel_manager,
             provider,
             session_configuration.model_reasoning_effort,
@@ -919,6 +921,7 @@ impl Session {
             .models_manager
             .construct_model_family(session_configuration.model.as_str(), &per_turn_config)
             .await;
+        let models_etag = self.services.models_manager.get_models_etag().await;
         let mut turn_context: TurnContext = Self::make_turn_context(
             Some(Arc::clone(&self.services.auth_manager)),
             &self.services.otel_manager,
@@ -926,6 +929,7 @@ impl Session {
             &session_configuration,
             per_turn_config,
             model_family,
+            models_etag,
             self.conversation_id,
             sub_id,
         );
@@ -2105,6 +2109,7 @@ async fn spawn_review_thread(
         .models_manager
         .construct_model_family(&model, &config)
         .await;
+    let models_etag = sess.services.models_manager.get_models_etag().await;
     // For reviews, disable web_search and view_image regardless of global settings.
     let mut review_features = sess.features.clone();
     review_features
@@ -2137,6 +2142,7 @@ async fn spawn_review_thread(
         per_turn_config.clone(),
         auth_manager,
         model_family.clone(),
+        models_etag,
         otel_manager,
         provider,
         per_turn_config.model_reasoning_effort,
@@ -3163,6 +3169,7 @@ mod tests {
             &session_configuration,
             per_turn_config,
             model_family,
+            None,
             conversation_id,
             "turn_id".to_string(),
         );
@@ -3249,6 +3256,7 @@ mod tests {
             &session_configuration,
             per_turn_config,
             model_family,
+            None,
             conversation_id,
             "turn_id".to_string(),
         ));

codex-rs/core/src/openai_models/models_manager.rs

@@ -131,6 +131,10 @@ impl ModelsManager {
             .with_config_overrides(config)
     }
 
+    pub async fn get_models_etag(&self) -> Option<String> {
+        self.etag.read().await.clone()
+    }
+
     pub async fn get_model(&self, model: &Option<String>, config: &Config) -> String {
         if let Some(model) = model.as_ref() {
             return model.to_string();

codex-rs/core/tests/chat_completions_payload.rs

@@ -92,6 +92,7 @@ async fn run_request(input: Vec<ResponseItem>) -> Value {
         Arc::clone(&config),
         None,
         model_family,
+        None,
         otel_manager,
         provider,
         effort,

codex-rs/core/tests/chat_completions_sse.rs

@@ -93,6 +93,7 @@ async fn run_stream_with_bytes(sse_body: &[u8]) -> Vec<ResponseEvent> {
         Arc::clone(&config),
         None,
         model_family,
+        None,
         otel_manager,
         provider,
         effort,

codex-rs/core/tests/responses_headers.rs

@@ -86,6 +86,7 @@ async fn responses_stream_includes_subagent_header_on_review() {
         Arc::clone(&config),
         None,
         model_family,
+        None,
         otel_manager,
         provider,
         effort,
@@ -181,6 +182,7 @@ async fn responses_stream_includes_subagent_header_on_other() {
         Arc::clone(&config),
         None,
         model_family,
+        None,
         otel_manager,
         provider,
         effort,
@@ -275,6 +277,7 @@ async fn responses_respects_model_family_overrides_from_config() {
         Arc::clone(&config),
         None,
         model_family,
+        None,
         otel_manager,
         provider,
         effort,

codex-rs/core/tests/suite/client.rs

@@ -1146,6 +1146,7 @@ async fn azure_responses_request_includes_store_and_reasoning_ids() {
         Arc::clone(&config),
         None,
         model_family,
+        None,
         otel_manager,
         provider,
         effort,