Umbrella

Aave Umbrella is a modular, onchain risk management system that automates bad debt coverage for Aave v3 pools. It enables users to stake wrapped aTokens or GHO, and earn protocol rewards.

Umbrella is built from three main contract types:

To participate, users deposit supported assets (wrapped aTokens or GHO) into the appropriate StakeToken contract. This action mints shares representing their position. The StakeToken uses an exchange rate that starts at 1:1 and only decreases if slashing occurs.

Staking can be performed with a standard ERC20 approve and deposit, or with EIP-2612 permit signature using depositWithPermit. Users may also set a cooldown operator to manage their cooldowns.

IERC20 underlying = IERC20(stakeToken.asset());underlying.approve(address(stakeToken), amount);stakeToken.deposit(amount, msg.sender);

To withdraw, users must first activate a cooldown by calling cooldown(). The cooldown period is 20 days (configurable by governance), followed by a 2-day unstake window. During cooldown, rewards continue to accrue and funds remain slashable. Only one cooldown record is allowed per user at a time. If a user transfers shares after activating cooldown, the amount available for withdrawal is reduced. Depositing more after cooldown does not affect the cooldowned amount.

After the cooldown period, users can withdraw within the unstake window using redeem or withdraw. If the window is missed, the cooldown must be restarted. Withdrawals are always subject to the current exchange rate, which may have changed due to slashing.

stakeToken.cooldown();// ...wait for cooldown period...stakeToken.redeem(shares, msg.sender, msg.sender);

Slashing is triggered automatically by UmbrellaCore when a deficit in the corresponding Aave pool exceeds the configured offset. Slashing reduces total assets in the StakeToken, lowering the value of all shares. The contract enforces a minimum assets floor to prevent full depletion. Only UmbrellaCore (the owner) can call slash, and slashed assets are sent to the Aave Collector for deficit coverage.

function slash(uint256 amount) external onlyOwner;

Rewards are managed by the RewardsController, which supports up to 8 reward tokens per StakeToken. Emission rates are governed by a piecewise linear curve, targeting optimal liquidity. Below the target liquidity, rewards are boosted to attract stakers; at target, emission is maximized; above target, emission tapers off to discourage over-staking. Governance sets up new assets and rewards, while a Rewards Admin can adjust emission rates and distribution end times.

Users can claim all available rewards for their assets at any time, or authorize a claimer to do so on their behalf.

rewardsController.claimAllRewards([address(stakeToken)], msg.sender);

To claim a specific reward:

rewardsController.claimRewards(    [address(stakeToken)],    amount,    msg.sender,    rewardToken);

To set a claimer:

rewardsController.setClaimer(user, claimer);