diff --git a/codex-rs/rmcp-client/src/mcp_oauth_http.rs b/codex-rs/rmcp-client/src/mcp_oauth_http.rs
index 8c093102fd..3bcf870627 100644
--- a/codex-rs/rmcp-client/src/mcp_oauth_http.rs
+++ b/codex-rs/rmcp-client/src/mcp_oauth_http.rs
@@ -133,7 +133,7 @@ impl OAuthHttpClient {
                         name: OAUTH_DISCOVERY_HEADER.to_string(),
                         value: OAUTH_DISCOVERY_VERSION.to_string(),
                     }],
-                    None,
+                    /*body*/ None,
                     Some(DISCOVERY_TIMEOUT),
                 )
                 .await
diff --git a/codex-rs/rmcp-client/src/oauth.rs b/codex-rs/rmcp-client/src/oauth.rs
index 35d5be0c59..a26c24d962 100644
--- a/codex-rs/rmcp-client/src/oauth.rs
+++ b/codex-rs/rmcp-client/src/oauth.rs
@@ -876,7 +876,11 @@ mod tests {
 
         let persistor = OAuthPersistor::new(
             tokens.server_name.clone(),
-            OAuthHttpClient::new(Arc::new(FailingHttpClient), None, None)?,
+            OAuthHttpClient::new(
+                Arc::new(FailingHttpClient),
+                /*http_headers*/ None,
+                /*env_http_headers*/ None,
+            )?,
             OAuthCredentialsStoreMode::File,
             Some(tokens.clone()),
         );
@@ -904,7 +908,11 @@ mod tests {
 
         let persistor = OAuthPersistor::new(
             tokens.server_name.clone(),
-            OAuthHttpClient::new(Arc::new(FailingHttpClient), None, None)?,
+            OAuthHttpClient::new(
+                Arc::new(FailingHttpClient),
+                /*http_headers*/ None,
+                /*env_http_headers*/ None,
+            )?,
             OAuthCredentialsStoreMode::File,
             Some(tokens),
         );