diff --git a/src/agents/mcp-stdio-transport.test.ts b/src/agents/mcp-stdio-transport.test.ts
index f487fb2059c6..1764983b30ff 100644
--- a/src/agents/mcp-stdio-transport.test.ts
+++ b/src/agents/mcp-stdio-transport.test.ts
@@ -204,4 +204,23 @@ describe("OpenClawStdioClientTransport", () => {
       "write after end",
     );
   });
+
+  it("reports stderr pipe errors without an unhandled error crash", async () => {
+    const child = new MockChildProcess();
+    spawnMock.mockReturnValue(child);
+
+    const transport = new OpenClawStdioClientTransport({ command: "npx", stderr: "pipe" });
+    const onerror = vi.fn();
+    Object.assign(transport, { onerror });
+    const started = transport.start();
+    child.emit("spawn");
+    await started;
+
+    const error = new Error("simulated pipe error");
+    expect(() => child.stderr?.emit("error", error)).not.toThrow();
+    expect(onerror).toHaveBeenCalledWith(error);
+
+    child.stderr.write("server diagnostic");
+    expect(transport.stderr?.read()?.toString()).toBe("server diagnostic");
+  });
 });
diff --git a/src/agents/mcp-stdio-transport.ts b/src/agents/mcp-stdio-transport.ts
index 99ab66235f32..2e268128b803 100644
--- a/src/agents/mcp-stdio-transport.ts
+++ b/src/agents/mcp-stdio-transport.ts
@@ -86,6 +86,7 @@ export class OpenClawStdioClientTransport implements Transport {
       });
       child.stdout?.on("error", (error: Error) => this.onerror?.(error));
       if (this.stderrStream && child.stderr) {
+        child.stderr.on("error", (error: Error) => this.onerror?.(error));
         child.stderr.pipe(this.stderrStream);
       }
     });