1 Balance query 2 Debit reduces balance 3 Credit increases balance 4 Full round 5 Rollback restores balance 6 Multi-action round 7 Zero-win round 39 Authenticate successful 40 Authenticate returns balance

8 Idempotent debit replay 9 Idempotent credit replay 10 Idempotent rollback replay 43 Duplicate debit different params 44 Duplicate credit different params 45 Duplicate rollback different params

11 Insufficient funds 12 Rollback unknown tx 42 Authenticate invalid player

15 Wrong HMAC signature 16 Mismatched body HMAC 17 Tampered body 29 Replay attack (expired timestamp) 41 Authenticate HMAC required

18 Negative debit amount 19 Negative credit amount 20 Zero debit amount 21 Overflow amount 22 SQL injection in playerId 23 XSS in fields 24 Missing required fields 25 Extra unknown fields 26 Wrong Content-Type 27 Concurrent duplicates

30 Very long strings 31 Unicode/emoji 32 Decimal precision 33 Empty playerId 34 Rapid requests

35 Rollback before debit 37 Concurrent debit and rollback 38 Late debit after confirmed rollback