A small team shipped a CSV validation service.
It passed on a workstation.
It died three seconds after starting on a free server.
This article reconstructs that failure as a reproducible case.
It is not a benchmark and not a product review.
The point is to show a workflow for finding display dependencies before they reach production.
Two availability points made the loop cheap: free model access to draft a fix and a free server option to run headless checks.
Disclosure: This article was prepared as part of MonkeyCode's product outreach.
The article does not assert model names, quotas, hardware, or uptime guarantees beyond those availability points.
The case began with a small request.
The service needed to read a CSV file, reject rows with missing columns, and write a short JSON report.
The requirement said nothing about a desktop interface.
The generated entry point looked ordinary.
The local smoke test passed because it always supplied a file.
That path never touched the fallback.
The application then moved to a free server where the default start command had no file argument.
The server process reached the call and failed.
The problem was not a hallucinated algorithm.
The model added a graphical file picker as a hidden fallback.
On the workstation that fallback was harmless.
On a headless server it was a startup-time dependency.
A code review might have missed it because is a standard-library module and the fallback looked like convenience logic.
The environment mismatch only became visible when the no-argument path ran on a machine without a display.
The team turned the failure into a deploy gate.
The first artifact was a no-argument probe.
The probe expects the command to fail.
That expectation is important.
A CLI that starts without input on a headless server should exit with a controlled message, not open a file picker.
The fixed entry point removed the GUI branch.
The second artifact was a static scanner.
It walks the generated files and lists GUI module imports.
The scanner is not smart enough to replace the runtime probe, but it gives a fast signal before code reaches a server.
The value of the scanner is not completeness.
It is speed.
A scan can run in CI before a deployment is attempted.
The no-argument probe then runs on the free server as the authoritative check.
The two checks cover different failure classes.
Check Runtime What it catches What it misses Local smoke with workstation logic errors in the validation path fallback paths that need no argument No-argument probe free server startup GUI fallback and display dependencies GUI calls hidden behind unused flags Import scanner CI statically visible GUI imports dynamic imports and string-based execution The workflow fits a team that uses model output as a proposal.
The generated code is tested, not trusted.
The free server is the headless canary.
If a patch starts without a display, it has at least passed the first environment contract.
There are real limits.
The probe misses GUI calls in unused branches.
The scanner misses dynamic imports such as or code built from strings.
If the free server sets a virtual display, the runtime probe may return false confidence.
A service that deliberately needs a file picker should use a browser upload path or a display-capable runtime instead of hiding a desktop dependency in a CLI.
This approach is for headless services, not for desktop applications.
Teams that only run model output locally should not treat a passing workstation test as a deployment guarantee.
The environment is part of the test surface.
If a free server option is available, use it as a headless canary before the production deploy.
It costs less than discovering the display dependency from a user report.