fix(models): support single model lookup

Support single model lookup by replacing the one-segment models route
with a catch-all route that preserves capability kind paths while
allowing provider-prefixed IDs like cc/claude-sonnet-5.

src/app/api/v1/models/[...model]/route.js

@@ -0,0 +1,78 @@
+import { buildModelsList } from "../route.js";
+
+// URL slug → service kind(s). `web` covers both webSearch and webFetch.
+const KIND_SLUG_MAP = {
+  "image": ["image"],
+  "tts": ["tts"],
+  "stt": ["stt"],
+  "embedding": ["embedding"],
+  "image-to-text": ["imageToText"],
+  "web": ["webSearch", "webFetch"],
+};
+
+const LLM_KIND = "llm";
+
+export async function OPTIONS() {
+  return new Response(null, {
+    headers: {
+      "Access-Control-Allow-Origin": "*",
+      "Access-Control-Allow-Methods": "GET, OPTIONS",
+      "Access-Control-Allow-Headers": "*",
+    },
+  });
+}
+
+function json(data, options = {}) {
+  return Response.json(data, {
+    ...options,
+    headers: {
+      "Access-Control-Allow-Origin": "*",
+      ...options.headers,
+    },
+  });
+}
+
+/**
+ * GET /v1/models/{kind} - OpenAI-compatible models list filtered by capability.
+ * GET /v1/models/{provider}/{model} - OpenAI-compatible single model lookup.
+ * Supported kinds: image, tts, stt, embedding, image-to-text, web.
+ */
+export async function GET(_request, { params }) {
+  try {
+    const { model } = await params;
+    const path = Array.isArray(model) ? model : [model];
+    const identifier = path.filter(Boolean).join("/");
+    const kindFilter = path.length === 1 ? KIND_SLUG_MAP[identifier] : null;
+
+    if (kindFilter) {
+      const data = await buildModelsList(kindFilter);
+      return json({ object: "list", data });
+    }
+
+    // Match the same LLM catalog exposed by GET /v1/models. A catch-all
+    // parameter is required because provider-prefixed IDs contain a slash.
+    const models = await buildModelsList([LLM_KIND]);
+    const matchedModel = models.find((candidate) => candidate.id === identifier);
+
+    if (!matchedModel) {
+      return json(
+        {
+          error: {
+            message: `The model '${identifier}' does not exist or you do not have access to it.`,
+            type: "invalid_request_error",
+            code: "model_not_found",
+          },
+        },
+        { status: 404 },
+      );
+    }
+
+    return json(matchedModel);
+  } catch (error) {
+    console.log("Error fetching model:", error);
+    return json(
+      { error: { message: error.message, type: "server_error" } },
+      { status: 500 },
+    );
+  }
+}

src/app/api/v1/models/[kind]/route.js

@@ -1,55 +0,0 @@
-import { buildModelsList } from "../route.js";
-
-// URL slug → service kind(s). `web` covers both webSearch and webFetch.
-const KIND_SLUG_MAP = {
-  "image": ["image"],
-  "tts": ["tts"],
-  "stt": ["stt"],
-  "embedding": ["embedding"],
-  "image-to-text": ["imageToText"],
-  "web": ["webSearch", "webFetch"],
-};
-
-export async function OPTIONS() {
-  return new Response(null, {
-    headers: {
-      "Access-Control-Allow-Origin": "*",
-      "Access-Control-Allow-Methods": "GET, OPTIONS",
-      "Access-Control-Allow-Headers": "*",
-    },
-  });
-}
-
-/**
- * GET /v1/models/{kind} - OpenAI-compatible models list filtered by capability.
- * Supported kinds: image, tts, stt, embedding, image-to-text, web.
- */
-export async function GET(_request, { params }) {
-  try {
-    const { kind } = await params;
-    const kindFilter = KIND_SLUG_MAP[kind];
-
-    if (!kindFilter) {
-      return Response.json(
-        {
-          error: {
-            message: `Unknown model kind: ${kind}. Supported: ${Object.keys(KIND_SLUG_MAP).join(", ")}`,
-            type: "invalid_request_error",
-          },
-        },
-        { status: 404, headers: { "Access-Control-Allow-Origin": "*" } }
-      );
-    }
-
-    const data = await buildModelsList(kindFilter);
-    return Response.json({ object: "list", data }, {
-      headers: { "Access-Control-Allow-Origin": "*" },
-    });
-  } catch (error) {
-    console.log("Error fetching models by kind:", error);
-    return Response.json(
-      { error: { message: error.message, type: "server_error" } },
-      { status: 500 }
-    );
-  }
-}

tests/unit/v1-model-lookup-3588.test.js

@@ -0,0 +1,71 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const mocks = vi.hoisted(() => ({
+  buildModelsList: vi.fn(),
+}));
+
+vi.mock("../../src/app/api/v1/models/route.js", () => ({
+  buildModelsList: mocks.buildModelsList,
+}));
+
+const { GET } = await import("../../src/app/api/v1/models/[...model]/route.js");
+
+const chatModel = {
+  id: "cc/claude-sonnet-5",
+  object: "model",
+  owned_by: "cc",
+  context_length: 1_000_000,
+};
+
+function params(model) {
+  return { params: Promise.resolve({ model }) };
+}
+
+describe("GET /v1/models/{id}", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("retrieves a provider-prefixed model ID split across URL path segments", async () => {
+    mocks.buildModelsList.mockResolvedValue([chatModel]);
+
+    const response = await GET(new Request("https://router.test/v1/models/cc/claude-sonnet-5"), params(["cc", "claude-sonnet-5"]));
+
+    expect(response.status).toBe(200);
+    expect(await response.json()).toEqual(chatModel);
+    expect(mocks.buildModelsList).toHaveBeenCalledWith(["llm"]);
+  });
+
+  it("also handles a decoded slash in a single catch-all segment", async () => {
+    mocks.buildModelsList.mockResolvedValue([chatModel]);
+
+    const response = await GET(new Request("https://router.test/v1/models/cc%2Fclaude-sonnet-5"), params(["cc/claude-sonnet-5"]));
+
+    expect(response.status).toBe(200);
+    expect(await response.json()).toEqual(chatModel);
+  });
+
+  it("keeps capability-list routes unchanged", async () => {
+    const imageModel = { id: "image/gpt-image-1", object: "model", owned_by: "image" };
+    mocks.buildModelsList.mockResolvedValue([imageModel]);
+
+    const response = await GET(new Request("https://router.test/v1/models/image"), params(["image"]));
+
+    expect(response.status).toBe(200);
+    expect(await response.json()).toEqual({ object: "list", data: [imageModel] });
+    expect(mocks.buildModelsList).toHaveBeenCalledWith(["image"]);
+  });
+
+  it("returns an OpenAI-style model_not_found response for an unknown model", async () => {
+    mocks.buildModelsList.mockResolvedValue([chatModel]);
+
+    const response = await GET(new Request("https://router.test/v1/models/cc/missing-model"), params(["cc", "missing-model"]));
+    const body = await response.json();
+
+    expect(response.status).toBe(404);
+    expect(body.error).toMatchObject({
+      type: "invalid_request_error",
+      code: "model_not_found",
+    });
+  });
+});