Index: codex-rs/core/src/config/mod.rs
--- codex-rs/core/src/config/mod.rs.orig
+++ codex-rs/core/src/config/mod.rs
@@ -3265,7 +3265,7 @@ impl Config {
 
         let review_model = override_review_model.or(cfg.review_model);
 
-        let check_for_update_on_startup = cfg.check_for_update_on_startup.unwrap_or(true);
+        let check_for_update_on_startup = cfg.check_for_update_on_startup.unwrap_or(false);
         let model_catalog = load_model_catalog(cfg.model_catalog_json.clone())?;
 
         let log_dir = cfg
