hyTOKEN / ERC-7575 (design only)

Not production

Compounders (hc…) and hyTOKENS (hy…) are not live mainnet UX. Do not integrate them for production until addresses ship on market pages / mainnet-v1.json. Design source: baofinance/harbor-yield (doc/design.md, doc/integrations.md). Product: Harbor Yield. Tech: Harbor Yield contracts.

Product Levels 1–3 = design doc 0–2 (SP / Compounder / HarborYield). See Token taxonomy.

Standards (do not confuse)

Layer	Contract	Standard	What you integrate
Compounder (hcXXX.COLn)	Compounder_v1	ERC-4626 (+ EIP-2612)	Plain single-asset vault. asset() is the pegged token (haXXX), not the pool token.
hyTOKEN share (hyXXX)	HarborYield_v1	ERC-7575 share (+ ERC-20 / EIP-2612)	Multi-asset basket share. Not ERC-4626 — a single asset() would be a lie. Discovers doors via vault(asset).
hy entry/exit door	HarborYieldEntry_v1	ERC-7575 vault = ERC-4626 minus ERC-20	One door per holding. share() → hyXXX. Deposit/redeem that door’s asset(); doors mint/burn the shared hy share.

hyTOKEN is ERC-7575, not ERC-4626. The doors reuse the familiar ERC-4626 mutation surface (deposit / mint / withdraw / redeem / preview*), but the share token is split out onto hyXXX (ERC-7575’s share/vault split). For exits, approve hyXXX shares with the discovered door as spender (IERC20(hyXXX).approve(door, shares)), then call redeem / withdraw on the door.

door = IERC7575Share(hyXXX).vault(asset)   // discovery
IERC20(hyXXX).approve(door, shares)        // redeem path
IERC7575Vault(door).deposit(assets, receiver)
IERC7575Vault(door).redeem(shares, receiver, owner)

Also on hyXXX itself: fee-free redeemProportional (Harbor extension — slice of every holding). Per-asset door exits pay a basket-drift fee (preview* includes it; convertTo* does not).

Peg-priced ERC-4626-style views on hyXXX (totalAssets, convertToShares, …) exist for indexers; hy does not advertise IERC4626 via ERC-165.

Architecture (siblings, not a stack)

Compounder and HarborYield both wrap stability pools independently. Neither holds the other.

Product	Holds	Enter with
Compounder	One StabilityPool position	haXXX (standard ERC-4626 deposit)
HarborYield	Several pool positions directly + peg-equivalent ERC-4626 vaults (e.g. wstETH adapter)	Door asset() = market wrappedCollateral (pool holding) or the equivalent vault’s own asset

Do not asset-hunt for an ERC-4626 inside HY holdings for hy depositors — internal adapters are for the basket, not for hy holders. Follow vault(asset).

Integration sequences (ready when addresses ship)

These are the intended Phase 3 cookbooks — wire addresses into docs/@harbor/sdk when eng publishes them.

Compounder (ERC-4626)

1. Approve haXXX to the Compounder (or use permit).
2. Respect maxDeposit / maxMint (pool supply caps).
3. deposit(assets, receiver) or mint(shares, receiver).
4. Exit with withdraw / redeem. Optional: claim() for pro-rata pool rewards without exiting.
5. depositStabilityPool only if you already hold pool shares and want them wrapped.

hyTOKEN deposit (ERC-7575 door)

1. Resolve door = hy.vault(asset) for the wrappedCollateral or equivalent asset you hold.
2. Check door.maxDeposit(receiver).
3. Approve asset to the door, then door.deposit(assets, receiver) → receive hyXXX.
4. Deposits that cross the Minter are all-or-nothing (band / CR) — size against maxDeposit.

hyTOKEN exit

Path	Call	Fee
Whole basket	hy.redeemProportional(shares, receiver)	Free; returns a slice of every holding (pool legs pay out in ha terms)
Single asset	Approve hyXXX to door, then door.redeem / withdraw	Basket-drift fee; use preview* for the fee-inclusive amount

Wrap door exits with your own min-out — ERC-4626 has no slippage arg.

Go-live checklist (eng + docs)

• Mainnet Compounder / hy / door addresses published
• Rows in market pages + mainnet-v1.json
• Optional: @harbor/sdk helpers for vault(asset) / door encode
• Remove “not production” banners on this page

Until then, integrate minter + stability pools only (Mint and redeem).