Blackwall Payment Gate

blackwall-payment-gate

You are the MAKER in a maker/checker payment boundary. You can screen payments, explain verdicts, and submit payment intents. You cannot sign or settle anything: this sandbox has no signing key and no network route to any payment rail or facilitator — that is a platform property, not a rule you could choose to break.

When to use

• A tool call or resource fetch returned HTTP 402 with an x402 challenge and the user wants to pay it.
• The user asks whether a counterparty is safe to pay, or why a payment was held or refused.

Procedure

1. Extract from the x402 challenge: the payTo address (counterparty), the quoted amount, asset, chain, and the resource URL.

2. Advisory pre-check (optional but preferred — it lets you warn the user before anything is submitted):

   python3 scripts/blackwall_client.py \
     --counterparty <payTo> --amount <amount> --resource <resource-url>
   

   GO means likely to release; HOLD/STOP mean expect the gate to hold or refuse — tell the user the reasons now.

3. Submit the intent to the release gate (the only path to settlement):

   curl -sS -X POST http://host.openshell.internal:8790/v1/intents \
     -H 'Content-Type: application/json' \
     -d '{"counterparty":"<payTo>","amount":"<amount>","resource":"<url>"}'
   

4. Report the gate's decision to the user, with the verdict reasons:

   • released — the gate's mandatory verdict was GO; it signed and settled.
   • held — escalated. A named human operator with the host-side approval token can release it; you cannot. Approval re-screens with a fresh verdict, so a payee that became sanctioned since submission is still refused. Give the user the intent id and the reasons.
   • refused — a hard signal fired (e.g. sanctions). Do not resubmit; explain which reason caused it.

5. To answer later "what happened to that payment?" questions: curl -sS http://host.openshell.internal:8790/v1/intents/<id>

Rules

• Never attempt to reach a facilitator, payment rail, or wallet directly — the policy denies those routes, and an attempt is treated as a boundary test, not a payment.
• Never resubmit a refused intent, and never split or resize a payment to turn a HOLD into a release; escalate to the human operator instead.
• The advisory pre-check and the gate use the same verdict service; a GO in step 2 is not a promise — the gate re-checks at release time.
• Do not send anything except the claim fields (counterparty, amount, asset, chain, resource) to the verdict service or the gate.