LeashPay

AI agents are starting to pay for APIs, compute and data, but giving an agent a wallet key means a single prompt injection or bug can drain it. LeashPay is a spending leash for AI agents enforced on-chain by a NEAR smart contract. The owner deposits funds into a vault and sets a policy: per-payment cap, daily cap, allow-listed recipients, owner approval above a threshold, a pause/kill switch, and a full on-chain audit log (NEP-297 events). The agent holds only a NEAR function-call access key that can call a single method, request_payment, so it can never withdraw, change its own limits or transfer directly - NEAR itself rejects those calls. Every request is paid, queued for approval, or blocked with a reason that stays in the log. The demo includes an AI agent chat that turns tasks like 'pay the weather API 0.5 NEAR' into payment requests, an owner console (balance, remaining allowance, approvals, kill switch, audit log with explorer links) and attack buttons showing prompt injection and key misuse being stopped. Live on NEAR testnet (vault.leashpay-c143d2.testnet), Rust contract with 24 unit tests, MIT licensed.