{"name":"ability-check","description":"Resolves a d20 ability check, skill check, attack roll, or saving throw for tabletop RPGs. Rolls a d20 with an optional modifier and advantage/disadvantage, compares to a DC, and reports total, success/failure, and natural-20 / natural-1. Seedable. Use it as a d20 check resolver API for any RPG.","price":"$0.005","method":"POST","input_schema":{"properties":{"dc":{"type":"number","description":"Difficulty class to beat. Omit to just get the roll."},"modifier":{"type":"number","description":"Total bonus/penalty added to the d20 (-20..40). Default 0."},"advantage":{"type":"boolean","description":"Roll twice, take the higher."},"disadvantage":{"type":"boolean","description":"Roll twice, take the lower."},"seed":{"type":"number","description":"Optional integer seed for a reproducible roll."}},"required":[]},"input_example":{"dc":15,"modifier":5,"advantage":true,"seed":2},"output_example":{"d20_rolls":[15,7],"natural_roll":15,"modifier":5,"total":20,"mode":"advantage","dc":15,"success":true,"critical_success":false,"critical_failure":false},"x402_payment_required":true,"x402_facilitator":"https://api.cdp.coinbase.com/platform/v2/x402"}