COVENANT：检查和调用付费 Agent API

# COVENANT — x402 payments + vault for agents COVENANT is payment infrastructure for AI agents on **Robinhood Chain (4663)**. It gates APIs with x402, settles payments in **USDG**, and provides an encrypted credential vault so secret values do not enter an agent prompt or context window. ## Safety boundary Start with discovery and inspection. Do **not** approve tokens, sign a `PaymentIntent`, settle a payment, mint an agent key, create a wallet, or store a secret unless the user explicitly asks for that action. Never print, persist, or repeat a private key, API key, or vault secret in chat output. ## Gateway selection Use the public gateway unless the user supplies a self-hosted endpoint: ```bash export COVENANT_GATEWAY="${COVENANT_GATEWAY:-https://gateway.covenantx402.com}" ``` For a self-hosted gateway: ```bash export COVENANT_GATEWAY="http://127.0.0.1:8792" ``` ## Safe discovery: inspect paid APIs first ```bash curl -sS "$COVENANT_GATEWAY/x402/apis" curl -si "$COVENANT_GATEWAY/x402/premium" ``` An unpaid request returns HTTP `402 Payment Required` with: - an `accepts[]` payment requirement in the JSON body; - a standards-compatible `Payment-Required` header for x402 v2 clients; - an `exact` per-call option and a `covenant-session` option for repeated calls. On the public Robinhood rail, the asset is USDG at `0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168` with 6 decimals. ## Approved payment flow Only continue after the user explicitly approves a payment. 1. Request a paid route and read its requirement. 2. Approve the advertised `extra.spender` to spend no more than the route price. 3. Sign the EIP-712 `PaymentIntent`: ```js { from, to: payTo, value: maxAmountRequired, validAfter, validBefore, nonce, resource } ``` Use this domain exactly: ```js { name: 'COVENANT', version: '1', chainId: 4663, verifyingContract: '0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168' } ``` 4. Submit `{ intent, signature }` to `POST /facilitator/settle`. 5. Replay the returned receipt as the `X-PAYMENT` header on the same resource request. The reference implementation is `examples/pay.js`. ## Paid sessions For repeated requests, select the `accepts[]` entry whose scheme is `covenant-session`. Set `resource: "session"` when settling. A successful response includes a session id and call budget; redeem calls with: ```bash curl -sS -X POST "$COVENANT_GATEWAY/session/redeem" \ -H 'content-type: application/json' \ -d '{"sessionId":"..."}' ``` No additional wallet signature or on-chain transaction is needed for each redemption. ## Agent identity and vault These are explicit write actions. Request user approval first. | Method | Path | Purpose | |---|---|---| | `POST` | `/keys` | Mint an agent API key; it is shown once. | | `POST` | `/vault/entries` | Encrypt and store a secret for that key. | | `POST` | `/vault/broker` | Resolve `{{secret_name}}` server-side and scrub readback. | | `POST` | `/wallets/create` | Create an agent wallet; its private key is shown once. | | `GET` | `/reputation/:address` | Inspect a tx-anchored payment reputation score. | ## Non-negotiable rules - Never put plaintext secrets in prompts, agent memory, logs, terminal recordings, or chat. - A `PaymentIntent` must expire within 600 seconds. - Each nonce is single-use; a replay is rejected. - Treat `X-PAYMENT` receipts as sensitive payment capability material until redeemed. - The public demo rail is **USDG on Robinhood Chain 4663**. Do not claim a successful payment until a settlement response and transaction receipt are available.