fix(agents): error on failed tts tool synthesis

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

@@ -41,4 +41,17 @@ describe("createTtsTool", () => {
     });
     expect(JSON.stringify(result.content)).not.toContain("MEDIA:");
   });
+
+  it("throws when synthesis fails so the agent records a tool error", async () => {
+    textToSpeechSpy.mockResolvedValue({
+      success: false,
+      error: "TTS conversion failed: openai: not configured",
+    });
+
+    const tool = createTtsTool();
+
+    await expect(tool.execute("call-1", { text: "hello" })).rejects.toThrow(
+      "TTS conversion failed: openai: not configured",
+    );
+  });
 });

src/agents/tools/tts-tool.ts

@@ -49,15 +49,7 @@ export function createTtsTool(opts?: {
         };
       }
 
-      return {
-        content: [
-          {
-            type: "text",
-            text: result.error ?? "TTS conversion failed",
-          },
-        ],
-        details: { error: result.error },
-      };
+      throw new Error(result.error ?? "TTS conversion failed");
     },
   };
 }