As others have said, this is a "feature" for Google, not a bug. There is no easy way to set a hard cap on billing on a project. I spent the better time of an hour trying to find it in the billing settings in GCP, only to land on reddit and figuring out that you could set a budget alert to trigger a Pub/Sub message, which triggers a Cloud Function to disable billing for the project. Insanity.
Call it for what it is, an antifeature, a trap for the user.
This is presumably by design: How can it be the vendor's fault if your custom billing protection implementation failed you at a critical time? Much harder to defend against a switch on their dashboard allowing billing overshoot.
having to glue pub/sub to a cloud function just to approximate a hard cap is the whole indictment. that's not a safety feature. that's you building your own brakes.
As the other user said - this would be an anti-feature and user hostile.
This is a sign that somehow there isn’t sufficient incentive to work on these features.
This is from my experience the same in AWS and Azure. I would love for a kill-switch if the usage goes above a critical threshold. 5 hours down time will not kill my app but a huge cloud bill might.
My favorite Google LLM benchmark is asking Gemini models to create a script that fetches API usage (just request counts) for a project from GCP.
100% failure rate.