Skill Submission

Skill name: zest-repay-primitive
Category: Infrastructure
HODLMM integration? No — Zest V2 protocol primitive; not HODLMM-related.

What it does

Repays a selected Zest V2 debt asset against an existing V2 debt position on Stacks mainnet. Single-asset repay via SP1A27KFY4XERQCCRCARCYD1CC5N7M6688BSYADJ7.v0-4-market.repay(ft, amount, on-behalf-of). One operator-selected amount (or --max for full repay), one transaction, one proof.

Mirrors the architectural pattern of #574 (zest-asset-deposit-primitive) and #572 (zest-borrow-asset-primitive):

• Imports @stacks/transactions, uses makeContractCall + broadcastTransaction, polls Hiro for tx_status: success
• PostConditionMode.Deny with wallet-side willSendLte(amount) postcondition
• Reads live state (market canonicality, repay ABI, position, debt index/next-index, wallet balance, gas, mempool depth) before planning or broadcasting
• JSON envelope: { status, action, data, error }
• Confirmation token: REPAY
• Primitive-only scope: no controller logic, no collateral withdraw, no swap, no oracle refresh (V2 repay path does not require Pyth)

Designed to be composed via Bun.spawn by leverage / unwind controllers — see the architectural-gap discussion on #606 (review).

Commands

Flags

• --wallet <stacks-address> (required)
• --repay-asset <symbol> — STX / sBTC / stSTX / USDC / USDH (STX maps to Zest wSTX)
• --amount <base-units> OR --max (full debt, sized as scaledDebt × next-index / 1e12)
• --on-behalf-of <stacks-address> — repay another account's debt (defaults to --wallet)
• --min-gas-reserve-ustx <uSTX> — defaults to 200_000
• --confirm=REPAY (required for run)
• --fee-ustx <uSTX> — defaults to 70_000
• --wait-seconds <seconds> — defaults to 240

Safety

• PostConditionMode.Deny with Pc.principal(wallet).willSendLte(amount) (STX path uses .ustx(), non-STX uses .ft(underlying, assetName))
• Blocks on pending mempool transactions for the sender
• Verifies all four Zest V2 contracts are canonical on Hiro before broadcast
• Verifies the repay public function exists in the live v0-4-market interface
• Verifies --repay-asset is borrow-enabled in the live registry and the wallet has a tracked debt position for it
• Verifies the wallet's balance of the repay asset (STX vs SIP-010) covers --amount
• Refuses without --confirm=REPAY
• Signer address must match --wallet

Output contract

{ "status": "success|blocked|error", "action": "doctor|status|plan|run", "data": {}, "error": null }

Proof obligations (run output)

• tx_status: success
• sender matches --wallet
• contract/function is v0-4-market.repay
• post-condition mode is deny
• post-repay Market-Vault position shows reduced scaledDebt for the repay asset

On-chain proof

Not yet attached. A funded-wallet test cycle (sBTC supplied as collateral → borrow STX → repay via this primitive → verify reduced scaledDebt on Hiro) will be appended as a follow-up comment once the test agent runs end-to-end.

Known constraints

• Mainnet only.
• STX is treated as Zest wSTX for the repay contract; the wallet sends uSTX and the protocol wraps internally.
• This skill only repays; it does not enable collateral, supply collateral, swap, borrow, withdraw, or rebalance.
• --max sizes the repay as scaledDebt × next-index / 1e12 to anticipate index drift between plan and broadcast; the protocol caps over-repays at the actual debt.
• Single-repay nonce safety only — cross-skill nonce serialization belongs in the existing nonce runtime primitives and later composed controllers.