Enable Celo buyback from FeeHandler and fee distributions

Overview

This proposal is the last proposal of the UltraGreen effort. It aims to enable the buyback of non-Celo assets (currently only Celo assets) for Celo, using the MentoFeeHandler.

It also enables the distribution of fees to the Carbon Offseting Fund created in CGP-0077, as described in CIP-52.

Proposed Changes

All transactions have `value=0``.

1. Setting beneficiary as the Carbon Offseting Fund
   • Destination: FeeHandler.setFeeBeneficiary(beneficiaryAddress)
   • Data: Carbon Offseting Fund address = 0xCe10d577295d34782815919843a3a4ef70Dc33ce
2. Adding cUSD to the buyback

• Destination: FeeHandler.addToken(tokenAddress, handlerAddress)
• Data: cUSD address = 0x765DE816845861e75A25fCA122bb6898B8B1282a, MentoFeeHandlerSeller address = 0x4eFa274B7e33476C961065000D58ee09F7921A74

3. Adding cEUR to the buyback

• Destination: FeeHandler.addToken(tokenAddress, handlerAddress)
• Data: cEUR address = 0xD8763CBa276a3738E6DE85b4b3bF5FDed6D6cA73, MentoFeeHandlerSeller address = 0x4eFa274B7e33476C961065000D58ee09F7921A74

4. Adding cREAL to the buyback

• Destination: FeeHandler.addToken(tokenAddress, handlerAddress)
• Data: cREAL address = 0xe8537a3d056DA446677B9E9d6c5dB704EaAb4787, MentoFeeHandlerSeller address = 0x4eFa274B7e33476C961065000D58ee09F7921A74

5. Set max slipage for cUSD
   • Destination: FeeHandler.setMaxSplippage(address token, uint256 newMax)
   • Data: cUSD address = 0x765DE816845861e75A25fCA122bb6898B8B1282a, 0.01e24 (1%)
6. Set max slipage for cEUR
   • Destination: FeeHandler.setMaxSplippage(address token, uint256 newMax)
   • Data: cEUR address = 0xD8763CBa276a3738E6DE85b4b3bF5FDed6D6cA73, 0.01e24 (1%)
7. Set max slipage for cREAL

• Destination: FeeHandler.setMaxSplippage(address token, uint256 newMax)
• Data: cREAL address, 0.01e24 (1%)

8. Set minimanl oracle reports for cUSD

• Destination: FeeHandler.setMinimumReports(address tokenAddress, uint256 newMininumReports)
• Data: cUSD address = 0x765DE816845861e75A25fCA122bb6898B8B1282a, 5

9. Set minimanl oracle reports for cEUR

• Destination: FeeHandler.setMinimumReports(address tokenAddress, uint256 newMininumReports)
• Data: cEUR address = 0xD8763CBa276a3738E6DE85b4b3bF5FDed6D6cA73, 5

10. Set minimanl oracle reports for cREAL

• Destination: FeeHandler.setMinimumReports(address tokenAddress, uint256 newMininumReports)
• Data: cREAL address = 0xe8537a3d056DA446677B9E9d6c5dB704EaAb4787, 5

Verification

Make sure to be using latest celocli, currently 3.1.1

Carbon fund address

celocli network:parameters -n https://forno.celo.org

In the section carbonOffsetting, the partner field.

Contract addresses

celocli network:contracts -n https://forno.celo.org

cUSD address -> StableToken cEUR address -> StableTokenEUR cREAL address -> StableTokenBRL

This proposals

celocli governance:show --proposalID=143 -n https://forno.celo.org

Risks

General contract risk: This is the first time the features in this proposal are deployed in production, although they were tested with the Canolli tesnet. Oracle Risk: in case the SortedOracles rate is manipulated, arbitragers (specially the ones using MEV) could be able to trade gainst the FeeHandler, but as the numbers are low the damage they can cause is very limited.

Useful Links

• CIP-52
• Ultragreen Money — Celo’s Expanded Sustainability Commitment