Long-Horizon Agents Are Here. Full Autopilot Isn't

A good sanity check for long-horizon agents is not a benchmark. It is a task that is easy to verify and hard to fake. That is why I still like my small hyperlink_button experiment so much. On paper, it sounds trivial: a Streamlit control that looks like a text link but behaves like a button. In reality, it is exactly the kind of task that exposes whether an agent can actually work. The task is small enough that you can tell if it succeeded. But it is also awkward enough to matter: Python on the Streamlit side, React/TypeScript on the frontend side, packaging, integration, docs, testing, and all the usual places where “looks plausible” is not the same as “works.” That is why I think this kind of project is a better test than a flashy benchmark. The real question is not whether a model can emit code. The real question is whether the workflow around it can keep it honest: make it read the right docs, implement the actual requirement, and prove it did not cheat. That question feels especia