Catastrophe audit.
Five questions. The thought stays in the head until it is written. Once written, it can be examined.
Audit complete.
Three sections. The thought, the evidence, the next twenty minutes.
The thought you typed
The evidence
The next twenty minutes
Set a timer for 20 minutes. Do this. Then come back to this tool and tell yourself whether the thought softened.
Past audits.
The thoughts you have logged, in order. Note which ones recur.