The Agreement Eligibility is a Hats Protocol module that a community or organization can use to enable individuals to join the community by signing an agreement.

When an individual signs the agreement, they also receive a hat that grants them access to the community. If a new agreement is published, community members must sign the new agreement to continue to wear the hat and remain a member of the community.

The module is deployed and initialized by the organization. As a Hats Protocol module, it can be deployed via the Hats Module Factory. When the contract is deployed, the organization must specify the following parameters:

Immutable parameters:

• hatId — The hat id for the community hat

Mutable parameters:

• ownerHat — The hat id for the owner hat, i.e., the hat whose wearer is authorized to publish new agreements
• arbitratorHat — The hat id for the arbitrator hat, i.e. the hat whose wearer is authorized to revoke the community hat from a given community member
• agreement — The initial agreement, in the form of a hash. This is typically a CID pointing to a file containing the plaintext of the agreement.

Anyone can make themselves eligible for the hat by signing the agreement. There are two options of doing so:

1. Signing the agreement and claiming the hat, in one transaction. Doing so involves calling the signAgreementAndClaimHat function. The function receives as an input a Multi Claims Hatter instance, which will be used for claiming the hat.

2. Only signing the agreement, using the signAgreement function.

When a new agreement is published by the organization (see below), all current wearers of the community hat — i.e., active members of the community — must sign the new agreement within a specified time period to remain a member of the community.

This specified time period is called the "grace period" and is set by the wearer of the Owner Hat when publishing the new agreement.

Active community members can sign the new agreement by calling the signAgreement() function, which emits an event reflecting the member's "signature" of the new agreement.

The wearer of the ownerHat can publish a new agreement by calling the setAgreement() function. Just like initialization, this involves passing both the agreement and grace parameters. This action also increments the currentAgreementId.

Once a new agreement is set, the grace period begins.

The wearer of the arbitratorHat can revoke a community member's hat by calling the revoke() function. This function takes a single parameter, wearer, which is the address of the community member whose hat is being revoked.

When a hat is revoked, the hat is burned and the member is placed in badStanding within Hats Protocol. This means that the member is no longer eligible to wear the community hat and cannot re-claim the community hat until the arbitrator places them back in good standing.

If an individual's community hat has been revoked, then they are in bad standing. If the wearer of the arbitratorHat believes that the individual has made up for the behavior that led to the revocation, they can call the forgive() function. This places the individual back in good standing, enabling them to claim the community hat again if they so choose.

This contract also serves as an Eligibility module for the community hat. This means that it implements the IHatsEligibility interface, i.e. the getWearerStatus() function. This function returns the eligible and standing status for the given address.

These wearer statuses will differ depending on the scenario, as outlined in the table below.

This repo uses Foundry for development and testing. To get started:

1. Fork the project
2. Install Foundry
3. To compile the contracts, run forge build
4. To test, run forge test