diff --git a/rust/crates/api/src/providers/mod.rs b/rust/crates/api/src/providers/mod.rs
index 8f846cbe..002c9571 100644
--- a/rust/crates/api/src/providers/mod.rs
+++ b/rust/crates/api/src/providers/mod.rs
@@ -689,12 +689,9 @@ pub fn model_token_limit(model: &str) -> Option<ModelTokenLimit> {
             max_output_tokens: 16_384,
             context_window_tokens: 200_000,
         }),
-        // Generic fallback for any model: assume 128K context, 8K output.
-        // This prevents the "unknown model → no limit check → context overflow" bug.
-        _ => Some(ModelTokenLimit {
-            max_output_tokens: 8_192,
-            context_window_tokens: 131_072,
-        }),
+        // Unknown models return None so preflight skips the context-window
+        // check and lets the API enforce its own limits.
+        _ => None,
     }
 }