fix(cli): fail empty local model probes

src/cli/capability-cli.test.ts

@@ -419,6 +419,24 @@ describe("capability cli", () => {
     );
   });
 
+  it("fails local model probes when the provider returns no text output", async () => {
+    mocks.completeWithPreparedSimpleCompletionModel.mockResolvedValueOnce({
+      content: [],
+    } as never);
+
+    await expect(
+      runRegisteredCli({
+        register: registerCapabilityCli as (program: Command) => void,
+        argv: ["capability", "model", "run", "--prompt", "hello", "--json"],
+      }),
+    ).rejects.toThrow("exit 1");
+
+    expect(mocks.runtime.error).toHaveBeenCalledWith(
+      expect.stringContaining('No text output returned for provider "openai" model "gpt-5.4"'),
+    );
+    expect(mocks.runtime.writeJson).not.toHaveBeenCalled();
+  });
+
   it("runs gateway model probes without chat-agent prompt policy or tools", async () => {
     await runRegisteredCli({
       register: registerCapabilityCli as (program: Command) => void,