NFT sweep vault

The Sweep Vault is a data-less, System-owned PDA derived from ["sweep-vault", mint]. Tensor moves the buyer's lamports with a System Program transfer, which requires exactly this kind of account. Only the SWEEP program can sign for it, and it only does so inside execute_sweep.

Security model

1. There is no instruction that transfers from the vault except execute_sweep. There is no admin withdraw, no close, and no way to change the recipient.
2. execute_sweep CPIs only into Tensor Marketplace buy_core, with instruction data built by the program — a caller cannot inject a different instruction. The vault is the only PDA signer.
3. Before the CPI, the program parses the Tensor ListState and the Core asset directly: the asset must belong to the launch's collection, the listing must be in SOL, not private to someone else, not cosigned, not expired, and priced at or below the caller's max_price, which itself must be ≤ the launch's immutable max NFT price.
4. The NFT buyer passed to Tensor must equal the launch's destination.
5. After the CPI, the program re-reads the asset and requires its owner to be the destination, and requires the vault to have spent no more than max_price (listing price + Tensor taker fee + royalties).
6. A SweepReceipt PDA per (launch, asset) makes it impossible to buy the same NFT twice — so a treasury destination cannot relist swept NFTs to drain the vault.
7. The launch's minimum sweep interval rate-limits spending.

Residual risk

Sweeps are permissionless, so a caller could pick a listing above the collection floor — but never above the launch's public max NFT price and never outside the collection. The reference keeper always picks the cheapest verified listing and applies an extra off-chain floor-multiplier policy.