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,

src/cli/capability-cli.ts

@@ -112,7 +112,7 @@ type CapabilityEnvelope = {
 const CAPABILITY_METADATA: CapabilityMetadata[] = [
   {
     id: "model.run",
-    description: "Run a one-shot text inference turn through the agent runtime.",
+    description: "Run a one-shot text inference turn through the selected model provider.",
     transports: ["local", "gateway"],
     flags: ["--prompt", "--model", "--local", "--gateway", "--json"],
     resultShape: "normalized payloads plus provider/model attribution",
@@ -570,6 +570,13 @@ function requireProviderModelOverride(
   };
 }
 
+function collectModelRunText(content: Array<{ type: string; text?: string }>): string {
+  return content
+    .map((block) => (block.type === "text" && typeof block.text === "string" ? block.text : ""))
+    .join("")
+    .trim();
+}
+
 async function runModelRun(params: {
   prompt: string;
   model?: string;
@@ -607,10 +614,12 @@ async function runModelRun(params: {
             : undefined,
       },
     });
-    const text = result.content
-      .map((block) => (block.type === "text" ? block.text : ""))
-      .join("")
-      .trim();
+    const text = collectModelRunText(result.content);
+    if (!text) {
+      throw new Error(
+        `No text output returned for provider "${prepared.selection.provider}" model "${prepared.selection.modelId}".`,
+      );
+    }
     return {
       ok: true,
       capability: "model.run",
@@ -618,14 +627,12 @@ async function runModelRun(params: {
       provider: prepared.selection.provider,
       model: prepared.selection.modelId,
       attempts: [],
-      outputs: text
-        ? [
-            {
-              text,
-              mediaUrl: null,
-            },
-          ]
-        : [],
+      outputs: [
+        {
+          text,
+          mediaUrl: null,
+        },
+      ],
     } satisfies CapabilityEnvelope;
   }