module for metadata stamping

codex-rs/protocol/src/item_metadata.rs

@@ -0,0 +1,17 @@
+use crate::models::ResponseInputItem;
+use crate::models::ResponseItemMessageMetadata;
+use crate::models::UserMessageType;
+
+pub fn stamp_user_message_type_on_input_item(item: &mut ResponseInputItem, kind: UserMessageType) {
+    let ResponseInputItem::Message { role, metadata, .. } = item else {
+        return;
+    };
+    if role != "user" {
+        return;
+    }
+    let mut metadata_value = metadata
+        .take()
+        .unwrap_or_else(|| ResponseItemMessageMetadata::new(None));
+    metadata_value.user_message_type = Some(kind);
+    *metadata = Some(metadata_value);
+}

codex-rs/protocol/src/lib.rs

@@ -5,6 +5,7 @@ pub mod approvals;
 pub mod config_types;
 pub mod custom_prompts;
 pub mod dynamic_tools;
+pub mod item_metadata;
 pub mod items;
 pub mod mcp;
 pub mod memory_citation;