diff --git a/codex-rs/protocol/src/models.rs b/codex-rs/protocol/src/models.rs
index ad955867d2..c455b0e99d 100644
--- a/codex-rs/protocol/src/models.rs
+++ b/codex-rs/protocol/src/models.rs
@@ -1934,6 +1934,7 @@ mod tests {
                 namespace: Some("mcp__codex_apps__gmail".to_string()),
                 arguments: "{\"top_k\":5}".to_string(),
                 call_id: "call-1".to_string(),
+                metadata: None,
             }
         );
     }