fix: address PR review feedback — test coverage, formatting, and config fallback

- Fix oxfmt formatting issue in image.ts (CI check failure)
- Add toHaveBeenCalledWith assertions to Google model normalization tests
  to verify normalized model IDs are passed to resolveModelWithRegistry
- Copy api field from configured model in config fallback, not just input,
  so custom providers with explicit api configs route through correct adapter
- Add dedicated tests for !imageProvider fallback in image-tool.test.ts
  covering both single-image and multi-image branches
- Fix type errors in test configs (missing reasoning/cost fields)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/agents/tools/image-tool.test.ts

@@ -883,3 +883,119 @@ describe("image tool response validation", () => {
     expect(text).toBe("hello");
   });
 });
+
+describe("image tool custom provider fallback (#33185)", () => {
+  const pngB64 = ONE_PIXEL_PNG_B64;
+  const priorFetch = global.fetch;
+  registerImageToolEnvReset(priorFetch, [
+    "OPENAI_API_KEY",
+    "ANTHROPIC_API_KEY",
+    "COPILOT_GITHUB_TOKEN",
+    "GH_TOKEN",
+    "GITHUB_TOKEN",
+  ]);
+
+  it("falls back to describeImageWithModel for single image when no media-understanding provider is registered", async () => {
+    await withTempAgentDir(async (agentDir) => {
+      await writeAuthProfiles(agentDir, {
+        version: 1,
+        profiles: {
+          "vllm:default": { type: "api_key", provider: "vllm", key: "sk-vllm-test" },
+        },
+      });
+      const cfg: OpenClawConfig = {
+        agents: {
+          defaults: {
+            model: { primary: "vllm/Qwen3.5" },
+            imageModel: { primary: "vllm/Qwen3.5" },
+          },
+        },
+        models: {
+          providers: {
+            vllm: {
+              baseUrl: "http://127.0.0.1:1234/v1",
+              models: [makeModelDefinition("Qwen3.5", ["text", "image"])],
+            },
+          },
+        },
+      };
+      const tool = createRequiredImageTool({ config: cfg, agentDir });
+
+      // Mock the fallback function at module level
+      const spy = vi
+        .spyOn(
+          await import("../../media-understanding/providers/image.js"),
+          "describeImageWithModel",
+        )
+        .mockResolvedValue({ text: "custom fallback ok", model: "Qwen3.5" });
+
+      const res = await tool.execute("t1", {
+        prompt: "Describe the image.",
+        image: `data:image/png;base64,${pngB64}`,
+      });
+
+      expect(spy).toHaveBeenCalledWith(
+        expect.objectContaining({
+          provider: "vllm",
+          model: "Qwen3.5",
+          prompt: "Describe the image.",
+        }),
+      );
+      const text =
+        (res.content?.find((b: { type: string }) => b.type === "text") as { text?: string })
+          ?.text ?? "";
+      expect(text).toBe("custom fallback ok");
+      spy.mockRestore();
+    });
+  });
+
+  it("falls back to describeImagesWithModel for multiple images when no media-understanding provider is registered", async () => {
+    await withTempAgentDir(async (agentDir) => {
+      await writeAuthProfiles(agentDir, {
+        version: 1,
+        profiles: {
+          "vllm:default": { type: "api_key", provider: "vllm", key: "sk-vllm-test" },
+        },
+      });
+      const cfg: OpenClawConfig = {
+        agents: {
+          defaults: {
+            model: { primary: "vllm/Qwen3.5" },
+            imageModel: { primary: "vllm/Qwen3.5" },
+          },
+        },
+        models: {
+          providers: {
+            vllm: {
+              baseUrl: "http://127.0.0.1:1234/v1",
+              models: [makeModelDefinition("Qwen3.5", ["text", "image"])],
+            },
+          },
+        },
+      };
+      const tool = createRequiredImageTool({ config: cfg, agentDir });
+
+      const spy = vi
+        .spyOn(
+          await import("../../media-understanding/providers/image.js"),
+          "describeImagesWithModel",
+        )
+        .mockResolvedValue({ text: "Image 1:\nfirst\n\nImage 2:\nsecond", model: "Qwen3.5" });
+
+      const res = await tool.execute("t1", {
+        prompt: "Compare these images.",
+        images: [`data:image/png;base64,${pngB64}`, `data:image/png;base64,${pngB64}`],
+      });
+
+      expect(spy).toHaveBeenCalledWith(
+        expect.objectContaining({
+          provider: "vllm",
+          model: "Qwen3.5",
+          prompt: "Compare these images.",
+        }),
+      );
+      expect(spy.mock.calls[0][0].images).toHaveLength(2);
+      spy.mockRestore();
+    });
+  });
+});

src/media-understanding/providers/image.test.ts

@@ -168,7 +168,9 @@ describe("describeImageWithModel", () => {
       text: "flash ok",
       model: "gemini-3-flash-preview",
     });
-    expect(resolveModelWithRegistryMock).toHaveBeenCalledOnce();
+    expect(resolveModelWithRegistryMock).toHaveBeenCalledWith(
+      expect.objectContaining({ provider: "google", modelId: "gemini-3-flash-preview" }),
+    );
     expect(getApiKeyForModelMock).toHaveBeenCalledWith(
       expect.objectContaining({
         profileId: "google:default",
@@ -211,7 +213,9 @@ describe("describeImageWithModel", () => {
       text: "flash lite ok",
       model: "gemini-3.1-flash-lite-preview",
     });
-    expect(resolveModelWithRegistryMock).toHaveBeenCalledOnce();
+    expect(resolveModelWithRegistryMock).toHaveBeenCalledWith(
+      expect.objectContaining({ provider: "google", modelId: "gemini-3.1-flash-lite-preview" }),
+    );
     expect(getApiKeyForModelMock).toHaveBeenCalledWith(
       expect.objectContaining({
         profileId: "google:default",
@@ -253,7 +257,9 @@ describe("describeImageWithModel", () => {
               {
                 id: "vllm/Qwen3.5",
                 name: "Qwen3.5",
-                input: ["image", "text"] as string[],
+                reasoning: false,
+                input: ["image", "text"] as Array<"text" | "image">,
+                cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
                 contextWindow: 128000,
                 maxTokens: 8192,
               },

src/media-understanding/providers/image.ts

@@ -77,12 +77,14 @@ async function resolveImageRuntime(params: {
       resolvedRef.provider,
     );
     const configuredModel = providerConfig?.models?.find(
-      (m) =>
-        m.id === resolvedRef.model ||
-        m.id === `${resolvedRef.provider}/${resolvedRef.model}`,
+      (m) => m.id === resolvedRef.model || m.id === `${resolvedRef.provider}/${resolvedRef.model}`,
     );
     if (configuredModel?.input?.includes("image")) {
-      model = { ...model, input: configuredModel.input } as Model<Api>;
+      model = {
+        ...model,
+        input: configuredModel.input,
+        ...(configuredModel.api ? { api: configuredModel.api } : {}),
+      } as Model<Api>;
     }
   }