Agents: add fallback reply for tool-only completions

src/agents/pi-embedded-runner/run/payloads.e2e.test.ts

@@ -145,6 +145,42 @@ describe("buildEmbeddedRunPayloads", () => {
     expect(payloads[0]?.text).toBe("All good");
   });
 
+  it("adds completion fallback when tools run successfully without final assistant text", () => {
+    const payloads = buildPayloads({
+      toolMetas: [{ toolName: "write", meta: "/tmp/out.md" }],
+      lastAssistant: makeAssistant({
+        stopReason: "stop",
+        errorMessage: undefined,
+        content: [],
+      }),
+    });
+
+    expect(payloads).toHaveLength(1);
+    expect(payloads[0]?.isError).toBeUndefined();
+    expect(payloads[0]?.text).toBe("✅ Done.");
+  });
+
+  it("does not add completion fallback when the run still has a tool error", () => {
+    const payloads = buildPayloads({
+      toolMetas: [{ toolName: "browser", meta: "open https://example.com" }],
+      lastToolError: { toolName: "browser", error: "url required" },
+    });
+
+    expect(payloads).toHaveLength(0);
+  });
+
+  it("does not add completion fallback when no tools ran", () => {
+    const payloads = buildPayloads({
+      lastAssistant: makeAssistant({
+        stopReason: "stop",
+        errorMessage: undefined,
+        content: [],
+      }),
+    });
+
+    expect(payloads).toHaveLength(0);
+  });
+
   it("adds tool error fallback when the assistant only invoked tools and verbose mode is on", () => {
     const payloads = buildPayloads({
       lastAssistant: makeAssistant({

src/agents/pi-embedded-runner/run/payloads.ts

@@ -294,7 +294,7 @@ export function buildEmbeddedRunPayloads(params: {
   }
 
   const hasAudioAsVoiceTag = replyItems.some((item) => item.audioAsVoice);
-  return replyItems
+  const payloads = replyItems
     .map((item) => ({
       text: item.text?.trim() ? item.text.trim() : undefined,
       mediaUrls: item.media?.length ? item.media : undefined,
@@ -314,4 +314,13 @@ export function buildEmbeddedRunPayloads(params: {
       }
       return true;
     });
+  if (
+    payloads.length === 0 &&
+    params.toolMetas.length > 0 &&
+    !params.lastToolError &&
+    !lastAssistantErrored
+  ) {
+    return [{ text: "✅ Done." }];
+  }
+  return payloads;
 }