[imagegen] preserve image generation start events

codex-rs/core/src/stream_events_utils.rs

@@ -133,6 +133,9 @@ pub(crate) async fn persist_image_generation_item(
     image_item: &mut ImageGenerationItem,
 ) -> Option<AbsolutePathBuf> {
     image_item.saved_path = None;
+    if image_item.result.is_empty() {
+        return None;
+    }
     let session_id = sess.thread_id.to_string();
     match save_image_generation_result(
         &turn_context.config.codex_home,

codex-rs/core/tests/common/responses.rs

@@ -812,6 +812,17 @@ pub fn ev_image_generation_call(
     })
 }
 
+pub fn ev_image_generation_call_added(id: &str, status: &str) -> Value {
+    serde_json::json!({
+        "type": "response.output_item.added",
+        "item": {
+            "type": "image_generation_call",
+            "id": id,
+            "status": status,
+        }
+    })
+}
+
 pub fn ev_function_call(call_id: &str, name: &str, arguments: &str) -> Value {
     serde_json::json!({
         "type": "response.output_item.done",

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

@@ -20,6 +20,7 @@ use codex_utils_absolute_path::AbsolutePathBuf;
 use core_test_support::responses::ev_assistant_message;
 use core_test_support::responses::ev_completed;
 use core_test_support::responses::ev_image_generation_call;
+use core_test_support::responses::ev_image_generation_call_added;
 use core_test_support::responses::ev_message_item_added;
 use core_test_support::responses::ev_output_text_delta;
 use core_test_support::responses::ev_reasoning_item;
@@ -372,6 +373,7 @@ async fn image_generation_call_event_is_emitted() -> anyhow::Result<()> {
 
     let first_response = sse(vec![
         ev_response_created("resp-1"),
+        ev_image_generation_call_added(call_id, "in_progress"),
         ev_image_generation_call(call_id, "completed", "A tiny blue square", "Zm9v"),
         ev_completed("resp-1"),
     ]);
@@ -422,6 +424,10 @@ async fn image_generation_call_event_is_emitted() -> anyhow::Result<()> {
 
     assert_eq!(begin.call_id, call_id);
     assert_eq!(started.0.id, call_id);
+    assert_eq!(started.0.status, "in_progress");
+    assert_eq!(started.0.revised_prompt, None);
+    assert_eq!(started.0.result, "");
+    assert_eq!(started.0.saved_path, None);
     assert!(started.1 > 0);
     assert_eq!(completed.0.id, call_id);
     assert!(completed.1 > 0);

codex-rs/protocol/src/models.rs

@@ -892,6 +892,7 @@ pub enum ResponseItem {
         #[serde(default, skip_serializing_if = "Option::is_none")]
         #[ts(optional)]
         revised_prompt: Option<String>,
+        #[serde(default)]
         result: String,
     },
     #[serde(alias = "compaction_summary")]
@@ -1811,6 +1812,26 @@ mod tests {
         );
     }
 
+    #[test]
+    fn response_item_parses_in_progress_image_generation_call_without_result() {
+        let item = serde_json::from_value::<ResponseItem>(serde_json::json!({
+            "id": "ig_123",
+            "type": "image_generation_call",
+            "status": "in_progress",
+        }))
+        .expect("in-progress image generation item should deserialize");
+
+        assert_eq!(
+            item,
+            ResponseItem::ImageGenerationCall {
+                id: "ig_123".to_string(),
+                status: "in_progress".to_string(),
+                revised_prompt: None,
+                result: String::new(),
+            }
+        );
+    }
+
     #[test]
     fn additional_permission_profile_is_empty_when_all_fields_are_none() {
         assert_eq!(AdditionalPermissionProfile::default().is_empty(), true);