# HealthChain USDC Payment Flow Readback — A$390 fixed packet

Buyer-specific no-spend readback for `Mosss-OS/healthchain` after merged PR #51.

- Proof PR: https://github.com/Mosss-OS/healthchain/pull/51
- Issue: https://github.com/Mosss-OS/healthchain/issues/24
- Price: A$390 fixed scope
- Contact: info@transhumanism.com.au
- Settlement after scope confirmation: USDC on Base or Polygon to `0x17D7251A8a8d60ab74d7D2B2d20D2a0389871729`, or invoice.

## Why now

PR #51 was merged on 2026-05-23. It fixed the HealthChain USDC hook path by reading `balanceOf` for the connected wallet, skipping balance reads when no wallet is connected, checking allowance before approval, waiting for approval receipts before transfer, and tracking the final transfer hash. The next commercial step is a concise no-spend payment-flow contract so users and maintainers know which wallet, allowance, approval and receipt states are safe before real payments depend on it.

## Deliverables

1. Wallet/payment state table covering connect, wrong chain, no wallet, balance unavailable, allowance sufficient/insufficient and receipt-confirmation paths.
2. Mocked fixture plan for `balanceOf`, `allowance`, approval receipt, transfer receipt, revert and user-reject paths.
3. Regression checklist around `requiresUSDCApproval`, disabled button states, duplicate-click prevention, hash display and final receipt confirmation.
4. User-facing copy for safe retries, pending approval, failed transfer, unsupported wallet and support escalation.
5. GitHub appendix maintainers can paste into a follow-up issue, release note or QA checklist.

## Boundaries

No wallet signing, token approval, transfer, bridge, swap, spend, private keys, paid calls or legal/payment-term acceptance. If a live paid settlement trace is ever requested, Peter approval is required first.