AIP 4: Remove Pause Functions from Token and Policy Source

AuthorBrandon Iles, Nithin Krishna, Ahmed Naguib Aly

Simple Summary

Proposal to remove the pause functions in the AMPL ERC-20 and Supply Policy contracts.


There are currently two admin-callable functions, setRebasePaused and setTokenPaused, that were included in the initial deployment as emergency controls. They were meant to:

  • Facilitate the launch itself
  • Guard balances in critical situations post-launch

As stated in the pre-launch governance post:

We view both of these emergency switches as options of last resort and hope they never have to be enabled. We felt it was most responsible to launch with these in place, especially in the early days when the system is new and proving its worth in an adversarial environment.

It has now been over a year. After unpausing the system at the time of launch with Bitfinex, there has been no need to enable either of these. Now that the implementation of the AMPL token and the Supply Policy have had time to prove themselves, we believe it’s time they are removed.


setRebasePaused fixes the supply of the token until rebase is unpaused–the supply stays constant and Amples are still freely tradable by anyone. This was to guard against unexpected problems in the supply policy or oracle system upstream of the token.

setTokenPaused pauses all transfers on chain. This was meant to guard balances against unexpected problems in the token itself. It was also a guard used to help facilitate the launch before listing.

Removing these two functions decreases both “Centralization Risk” and “Integration Risk”.


As long as these functions exist, they are open to misuse by whoever controls the admin key (currently a 2-of-n multisig wallet owned by the development team).

Even as the Ampleforth governance process decentralizes, we’d like to keep the governance surface area as small as possible to avoid complexity and potential for exploits.

Secondly, Pausability increases the risk for outside platforms which build with AMPL. Not every platform is willing (or able) to implement logic that safely handles failed transfers of paused tokens. This may harm AMPL’s ability to support the wider DeFi ecosystem.


The OpenZeppelin AdminUpgradabilityProxy will be used to update the implementation of UFragments. The two pause functions would be removed. Special care will be taken to ensure no changes are made to the storage layout.

Copyright and related rights waived via CC0.