okx-agent-payments-protocol

⚠️ READ FIRST — ZERO-TEXT-ON-TRIGGER + NEVER-SKIP-USER-GATES. Between detecting a 402 (or any trigger word below) and emitting either the recommendation card (Step A3.5) or the single-candidate confirmation card (Step A4), output ZERO user-visible text. Zero. No 'received 402', no 'triggered OKX Agent Payments Protocol', no 'detected N schemes', no enumeration of schemes / networks / tokens / amounts, no 'loading skill', no '正在处理 / 触发 / 检测到 / 收到'. The skill-load tool call may happen but emits no surrounding prose. Exactly one user-confirmation card runs per payment: A3.5's recommendation card (when 2+ candidates and user picks `yes`) OR A4's confirmation card (when 1 candidate, OR when the user picked an alternative from A3.5's expanded list). Do NOT skip the applicable card on your own initiative under the pretext of 'past user preference' / 'streamlining' / 'they already confirmed once' — those preferences do not exist. Equally, do NOT render both cards back-to-back with the same info — after `yes` on A3.5.5, go directly to Step A5. The next user-visible text after detection MUST be one of the two cards. Unified payment dispatcher covering x402 (`exact` / `exact+Permit2` / `upto` / `aggr_deferred` schemes), MPP (`charge` / `session` intents), and a2a-pay (`a2a_charge` paymentId flow). Detects HTTP 402 protocol from response headers and routes to the matching scheme/intent reference; also handles a2a paymentId mentions without a 402. Loads `references/exact.md` (x402 exact scheme — full EIP-3009 TEE or local-key fallback), `references/aggr_deferred.md` (x402 aggr_deferred scheme — Session Key Ed25519 with sessionCert), `references/upto.md` (x402 upto scheme — cap-style metered billing via Permit2 with facilitator-bound witness; also covers `exact + Permit2` sub-mode where buyer output uses `permit2Authorization`), `references/charge.md` (MPP one-shot charge in transaction or hash mode, with splits), `references/session.md` (MPP channel: open + voucher loop + topUp + close, with state echo), or `references/a2a_charge.md` (a2a-pay create / pay / auto-poll status). Returns a ready-to-paste authorization header (x402 / MPP) or a tx-hash + status (a2a). Trigger words (English): '402', 'payment required', 'mpp', 'machine payment', 'pay for access', 'payment-gated', 'WWW-Authenticate: Payment', 'x402', 'x402Version', 'PAYMENT-REQUIRED', 'PAYMENT-SIGNATURE', 'X-PAYMENT', 'permit2', 'permit2Authorization', 'upto', 'metered billing', 'pay by usage', 'cap-style payment', 'settlement-overrides', 'open channel', 'voucher', 'session payment', 'close channel', 'topup channel', 'top up channel', 'settle channel', 'settle session', 'refund channel', 'channelId', 'channel_id', 'paymentId', 'a2a_', 'a2a payment', 'create payment link', 'payment link', 'payment status'. Trigger words (Chinese): '按量计费', '支付上限', '支付通道', '关闭通道', '关闭会话', '关闭支付通道', '充值通道', '续费通道', '结算通道', '结算会话', '关单', '凭证', '会话支付', '付款链接', '创建支付', '支付状态'. Critical sensitivity rule: any user mention of close / topup / settle / voucher / refund near a `channel_id`, `0x...` channel hash, or 'session' / 'channel' context = MPP mid-session operation — load this skill, jump into `references/session.md`, do NOT search for a separate close/topup tool.