fix(models): accept "responses" as a supported endpoint

src/shared/constants/modelSupportedEndpoints.ts

@@ -1,5 +1,6 @@
 export const MODEL_SUPPORTED_ENDPOINT_VALUES = [
   "chat",
+  "responses",
   "embeddings",
   "rerank",
   "images",
@@ -37,6 +38,8 @@ export function classifyModelSupportedEndpoints(endpoints: readonly string[]): {
   type?: "embedding" | "rerank" | "image" | "video" | "audio";
   subtype?: "speech" | "transcription";
 } {
+  // "chat" and "responses" are text-conversation endpoints; they carry no
+  // modality type, so they fall through to the empty return below.
   if (endpoints.includes("embeddings")) return { type: "embedding" };
   if (endpoints.includes("rerank")) return { type: "rerank" };
   if (endpoints.includes("images")) return { type: "image" };

tests/unit/model-supported-endpoints.test.ts

@@ -6,6 +6,7 @@ import {
   MODEL_SUPPORTED_ENDPOINT_VALUES,
   normalizeModelSupportedEndpoints,
 } from "../../src/shared/constants/modelSupportedEndpoints.ts";
+import { providerModelMutationSchema } from "../../src/shared/validation/schemas/provider.ts";
 
 test("normalizes legacy video and audio metadata to operation-specific endpoint ids", () => {
   assert.deepEqual(normalizeModelSupportedEndpoints(["chat", "video", "audio"]), [
@@ -56,3 +57,18 @@ test("classifies operation-specific media endpoints for the model catalog", () =
     type: "audio",
   });
 });
+
+test("accepts the responses endpoint emitted by Codex discovery", () => {
+  assert.ok(MODEL_SUPPORTED_ENDPOINT_VALUES.includes("responses"));
+  assert.deepEqual(normalizeModelSupportedEndpoints(["responses"]), ["responses"]);
+  // A responses-only model is a plain chat-type model: no media type override.
+  assert.deepEqual(classifyModelSupportedEndpoints(["responses"]), {});
+
+  const parsed = providerModelMutationSchema.safeParse({
+    provider: "codex",
+    modelId: "gpt-6-sol",
+    supportedEndpoints: ["responses"],
+  });
+  assert.equal(parsed.success, true);
+  assert.deepEqual(parsed.success && parsed.data.supportedEndpoints, ["responses"]);
+});