add uuid to metadata

codex-rs/protocol/src/models.rs

@@ -267,6 +267,47 @@ pub struct ResponseItemMetadata {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional)]
     pub user_message_type: Option<UserMessageType>,
+    /// Client-visible UUID generated by Codex for this item.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[ts(optional)]
+    pub uuid: Option<String>,
+}
+
+impl ResponseItem {
+    /// Ensures message metadata includes a generated UUID.
+    pub fn with_generated_metadata_uuid(self) -> Self {
+        match self {
+            ResponseItem::Message {
+                id,
+                role,
+                content,
+                metadata,
+                end_turn,
+                phase,
+            } => {
+                let metadata = ensure_generated_metadata_uuid(metadata);
+                ResponseItem::Message {
+                    id,
+                    role,
+                    content,
+                    metadata,
+                    end_turn,
+                    phase,
+                }
+            }
+            other => other,
+        }
+    }
+}
+
+fn ensure_generated_metadata_uuid(
+    metadata: Option<ResponseItemMetadata>,
+) -> Option<ResponseItemMetadata> {
+    let mut metadata = metadata.unwrap_or_default();
+    if metadata.uuid.is_none() {
+        metadata.uuid = Some(uuid::Uuid::new_v4().to_string());
+    }
+    Some(metadata)
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, JsonSchema, TS)]
@@ -2958,4 +2999,51 @@ mod tests {
 
         Ok(())
     }
+
+    #[test]
+    fn generates_metadata_uuid_for_message_items() -> Result<()> {
+        let item = ResponseItem::Message {
+            id: Some("msg_123".to_string()),
+            role: "assistant".to_string(),
+            content: vec![ContentItem::OutputText {
+                text: "hello".to_string(),
+            }],
+            metadata: Some(ResponseItemMetadata {
+                user_message_type: Some(UserMessageType::Prompt),
+                uuid: None,
+            }),
+            end_turn: None,
+            phase: None,
+        };
+
+        let surfaced = item.with_generated_metadata_uuid();
+        let serialized = serde_json::to_value(&surfaced)?;
+        let metadata = serialized
+            .get("metadata")
+            .and_then(serde_json::Value::as_object)
+            .expect("metadata should be present");
+        let uuid = metadata
+            .get("uuid")
+            .and_then(serde_json::Value::as_str)
+            .expect("uuid should be present");
+
+        uuid::Uuid::parse_str(uuid).expect("uuid should be valid");
+
+        assert_eq!(serialized.get("type"), Some(&serde_json::json!("message")));
+        assert_eq!(
+            serialized.get("role"),
+            Some(&serde_json::json!("assistant"))
+        );
+        assert_eq!(
+            serialized.get("content"),
+            Some(&serde_json::json!([{ "type": "output_text", "text": "hello" }]))
+        );
+        assert_eq!(
+            metadata.get("user_message_type"),
+            Some(&serde_json::json!("prompt"))
+        );
+        assert_ne!(uuid, "msg_123");
+
+        Ok(())
+    }
 }