fix(combo): fall through on pinned 401 responses (#12818)

* fix(combo): fall through on pinned 401 responses

* test(combo): cover pinned 401 in existing fallback regression

---------

Co-authored-by: Hermes Freebrain <freebrain@localhost>

changelog.d/fixes/0000-pinned-401-combo-fallback.md

@@ -0,0 +1 @@
+- **Combo routing:** a context-cache-pinned model that returns `401` now falls through to the normal combo fallback loop instead of terminating the request, allowing other eligible connections or providers to serve it.

open-sse/services/combo/dispatchPrelude.ts

@@ -247,7 +247,7 @@ async function evaluatePinnedResponse(args: {
     return null;
   }
   const pinnedStatus = pinnedResult.status || 500;
-  if (![408, 429, 500, 502, 503, 504].includes(pinnedStatus)) {
+  if (![401, 408, 429, 500, 502, 503, 504].includes(pinnedStatus)) {
     return pinnedResult;
   }
   log.warn(

tests/unit/combo-dispatch-prelude.test.ts

@@ -491,7 +491,7 @@ test("tryPinnedModelDispatch: expands the combo system_message template on the p
 });
 
 test("tryPinnedModelDispatch: fails over when the pinned model returns a transient status", async () => {
-  for (const status of [408, 429, 500, 502, 503, 504]) {
+  for (const status of [401, 408, 429, 500, 502, 503, 504]) {
     const ctx = pinCtx();
     const { res } = await dispatchHealthyPin(
       ctx,