Is your prompt broken on the new model?

A new release can silently reformat JSON, rename a field, or blow past a length limit. Define the contract your output must keep and find the breakage in seconds — free, no signup, no API keys.

Baseline output (old model)

Candidate output (new model)

Output contract (assertions)

must be valid JSON
JSON must have key "confidence"
must not contain "```"
length at most "600"

Define your output contract and hit Check to see exactly which assertions a model change would break.