# History (20%)

> Vault history scoring for recent instability, unresolved incidents, and confirmed lifetime loss events.

History measures whether the vault has recently behaved like a stable production system.

This vector is weighted at 20%, equal to Control and Governance. Chronic instability can dampen otherwise-good vaults even when current asset, platform, and timelock inputs look strong.

## What It Measures

The history vector consumes vault-scoped event aggregates from the event log.

| Signal                           | Treatment                                                  |
| -------------------------------- | ---------------------------------------------------------- |
| Active Critical events           | Time-decayed penalty                                       |
| Active Warning events            | Time-decayed penalty with diminishing returns              |
| Confirmed lifetime Critical loss | Non-decaying penalty for loss-evidenced Critical events    |
| Clean recent history             | Small bonus when there are no recent or lifetime Criticals |

RatingChange events are excluded so the score does not consume its own output.

## Time Decay

Recent Critical and Warning events matter most.

| Age bucket | Weight |
| ---------- | ------ |
| ≤ 30 days  | 1.0    |
| ≤ 90 days  | 0.6    |
| ≤ 180 days | 0.4    |
| ≤ 365 days | 0.2    |

Events outside the scoring window do not contribute to the time-decayed component.

## Warning Diminishing Returns

Warnings are compressed with a logarithmic count. The first few Warnings are a meaningful instability signal, while very high-frequency curator operations should not count linearly forever.

This preserves rank order while preventing routine operational chatter from forcing every active curator into the same outcome.

## Lifetime Critical Loss Penalty

Confirmed Critical loss events do not fully decay. A vault with a proven loss event in its history carries a permanent penalty, capped so repeated historical losses do not drive the vector below zero by themselves.

The lifetime count is evidence-gated. Operational Criticals such as pauses or ownership changes remain time-decayed signals, but they are not treated as permanent loss events unless the record includes loss evidence.

## Tier Ceiling

History also applies a post-composite ceiling.

| History score | Ceiling |
| ------------- | ------- |
| < 4.0         | 4.9     |
| < 7.0         | 7.5     |
| ≥ 7.0         | none    |

The ceiling exists to prevent a vault with chaotic recent history from publishing above the tier its operating record supports.