08 Troubleshooting

Most Express failures come from missing middleware, untyped bodies, stream buffering, or errors bypassing next(error).

req.body Is Undefined

Mount JSON parsing before the router:

app.use(express.json({ limit: "1mb" }));
app.use("/api", supportRouter);

Validation Returns 500

Use safeParse for request validation. Reserve error middleware for unexpected failures.

const parsed = SupportRequest.safeParse(req.body);

if (!parsed.success) {
  return res.status(400).json({ error: { code: "bad_request" } });
}

Stream Does Not Flush

Set application/x-ndjson, call res.write(...), and check proxy buffering.

res.setHeader("Content-Type", "application/x-ndjson");
res.write(chunk);

Provider Failures Leak Details

Route handlers should call next(error), and centralized error middleware should return a stable error shape.

Request Times Out

Raise Node, proxy, and platform timeouts for agent endpoints. For long approvals, use human-in-the-loop storage instead of holding an HTTP request open indefinitely.

Next

Add reviewer workflows in Human in the Loop. Related guides: Tool Errors, Readable Streams, and Tracing.