What I was looking for
Which account field really says how much GPU credit you can spend.
What I found
CreditWatch read a GPU provider's account endpoint. The schema documents balance as the account figure. Against a live account, the spendable number was credit, and the API paths needed trailing slashes the docs never mentioned.
Neither would have surfaced from reading. Both were found in one verification pass against a real account, and the finding is quoted in the changelog rather than hidden in a commit.
The move
Before I build on an API, I point the code at a live account and compare every field I depend on.