fix(ui): only check classifier/embedding models the config actually submits

missingReferencedModels read complexityRouterConfig.classifier_llm_config and embeddingModel unconditionally, but buildComplexityRouterConfig only includes classifier_llm_config when classifierType is "llm" and embedding_model when semanticMatchingEnabled is on. A dormant selection left over from a toggle no longer in effect (embeddingModel still set after turning semantic matching off, or a classifier_llm_config seeded with model: "" before a caller picks one) was being checked and reported as a missing model that would never actually be submitted, wrongly disabling the button.

Gate both fields on the same conditions buildComplexityRouterConfig itself uses. Also hardened getRequiredModels to filter out empty-string models, not just null/undefined, so a not-yet-chosen classifier model can't be misread as a real reference even when its field is legitimately included.

ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.tsx

@@ -201,12 +201,16 @@ const AddAutoRouterTab: React.FC<AddAutoRouterTabProps> = ({
 
   // Checks the config actually being built, not which preset (if any) it came from: a model that
   // was available when it entered a tier, whether via a preset or picked by hand, can have gone
-  // missing since (the caller's access narrowed, or a background refetch never caught it).
+  // missing since (the caller's access narrowed, or a background refetch never caught it). Only
+  // includes classifier_llm_config/embedding_model when buildComplexityRouterConfig would actually
+  // emit them (classifierType === "llm", semanticMatchingEnabled) - otherwise a dormant selection
+  // left over from a toggle no longer in effect would block submit for a model that never ships.
   const missingReferencedModels = getMissingModels(
     {
       tiers: complexityRouterConfig.tiers,
-      classifier_llm_config: complexityRouterConfig.classifier_llm_config,
-      embedding_model: embeddingModel,
+      classifier_llm_config:
+        complexityRouterConfig.classifier_type === "llm" ? complexityRouterConfig.classifier_llm_config : undefined,
+      embedding_model: semanticMatchingEnabled ? embeddingModel : undefined,
     },
     availableModelSet,
   );

ui/litellm-dashboard/src/lib/autorouter_presets.test.ts

@@ -4,6 +4,7 @@ import {
   getPresetByKey,
   getRequiredModelsInPreset,
   getMissingModelsInPreset,
+  getRequiredModels,
 } from "./autorouter_presets";
 
 describe("autorouter_presets", () => {
@@ -49,4 +50,15 @@ describe("autorouter_presets", () => {
     );
     expect(getMissingModelsInPreset(preset, new Set(required))).toEqual([]);
   });
+
+  // A classifier_llm_config placeholder is seeded with model: "" before a caller picks one; an
+  // empty string is not a real model reference and must not be reported as an unavailable model.
+  it("does not treat an empty-string classifier or embedding model as a required model", () => {
+    const required = getRequiredModels({
+      tiers: { SIMPLE: ["gpt-5-nano"], MEDIUM: [], COMPLEX: [], REASONING: [] },
+      classifier_llm_config: { model: "" },
+      embedding_model: "",
+    });
+    expect(required).toEqual(new Set(["gpt-5-nano"]));
+  });
 });

ui/litellm-dashboard/src/lib/autorouter_presets.ts

@@ -30,7 +30,9 @@ export const getRequiredModels = (
 ): Set<string> => {
   const { tiers, classifier_llm_config: classifier, embedding_model: embedding } = config;
   const models = [...tiers.SIMPLE, ...tiers.MEDIUM, ...tiers.COMPLEX, ...tiers.REASONING, classifier?.model, embedding];
-  return new Set(models.filter((model): model is string => model != null));
+  // Boolean(), not != null: an empty-string placeholder (e.g. classifier_llm_config seeded before a
+  // model is chosen) is never a real model reference either.
+  return new Set(models.filter((model): model is string => Boolean(model)));
 };
 
 export const getMissingModels = (