# Axiom / Clique <> Optimism Attestation Station + Citizen House
###### tags: `specs`
We propose to enhance Citizen House governance by allowing information from Attestation Station to be used to determine badgeholders. Specifically, we will build an on-chain service which:
* Ranks user addresses in Attestation Station according to metadata stored in attestations.
* Enables this information to be used in Citizen House governance for selection or weighting of badgeholders.
* For example, we can use [GitHub attestations](https://twitter.com/Clique2046/status/1633979988029632514) to give badgeholders variable weights (higher percentage of delegated tokens, instead of a uniform distribution for everyone) during RetroPGF (or any other engineering-focused decisions).
* Another option is to select badgeholders in different categories based on rankings derived from different types of attestations. For example, we can allocate 5 badges to the top Github star attestations and 5 badges to the top Github or Twitter follower attestations.
At present, the large volume of attestations in Attestation Station cannot be simultaneously accessed on-chain, making global statistics like a ranking impossible to compute. Our system will overcome this issue in the following steps:
* Use Axiom to read the value of all Clique attestations with a given key from Attestation Station at a fixed checkpoint block.
* Sort user addresses by values corresponding to a specific key and return the sorted list of the top values.
* Verify the Axiom-provided ZK validity proof on-chain and provide the ranked list of attestation values for usage in Citizen House badgeholder selection.
The outcome is a trustlessly determined ranking of users according to a metric from Attestation Station.
## Design Challenges
### Optimistic Challenge Period
We will post a Merkle root containing all the attestation information that's used in the ranking. Because the data is always available on-chain (it's just expensive for users to run the computation here), anyone can choose to challenge the ranking results during a challenge period of $X$ days.