# \[DRAFT\] Proposal: On-Chain Report Price Filter

**URL:** <https://forum.celo.org/t/draft-proposal-on-chain-report-price-filter/3725>\
**Category:** Mento\
**Created:** [June 2, 2022, 9:29pm UTC](https://forum.celo.org/t/draft-proposal-on-chain-report-price-filter/3725 "2022-06-02T21:29:37Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![bayological](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.celo.org/bayological/32/8381_2.png) [@bayological](https://forum.celo.org/u/bayological)\
**Post date:** [June 16, 2022, 11:28pm UTC](https://forum.celo.org/t/draft-proposal-on-chain-report-price-filter/3725/3 "2022-06-16T23:28:50Z")

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> [@diwu1989](#):
>
> Earlier this year when celo price pumped to double on that Korean exchange listing, if that happened again, what should the behavior be?

If that happens again, the first oracle reporting the new price will be filtered out. Once more oracles start reporting a similar price, the mean will get closer to this price, and any new oracle reports close to the new price will no longer be filtered. The same check is implemented in the oracle client [here](https://github.com/celo-org/celo-oracle/blob/main/src/aggregator_functions.ts#L116), and the behaviour should be the same.

> [@diwu1989](#):
>
> It was a huge instantaneous price change and all oracles saw the same pump and decided to stop reporting.

Currently, if the price deviation check fails, the oracle client will not send a report for that assigned block but should not stop reporting completely. The oracle client will stop reporting if the new price [trips the circuit breaker](https://github.com/celo-org/celo-oracle/blob/836c55e6b23683c479d506f3de2bd9d6015f7cca/src/reporters/base.ts#L358).

> [@diwu1989](#):
>
> It’s a little dangerous for official oracle to keep the old price and not report new price

There’s also another proposed change for an [on-chain circuit breaker](https://forum.celo.org/t/draft-proposal-on-chain-circuit-breaker/3786) that would have halted mento trading in this situation. Maybe Moola would benefit from this also, but I think all protocols should have protections in place when using oracles.

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