> ## Documentation Index
> Fetch the complete documentation index at: https://docs.devin.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# TailReplayInfo

> What a tail replay ( with a cursor) reports about the history it did not replay.

What a tail replay (`session/resume` with a `_cognition.ai/tail` cursor)
reports about the history it did not replay. Absent after a full replay.

## Properties

**historySkeleton** `HistorySkeletonAnchor[]` *required*

**Type:** `HistorySkeletonAnchor[]`

Top-level anchors of the whole history, oldest-first.

**olderIndex** `null | number` *required*

Ordinal of the oldest replayed event — the `startIndex` for the next
`_cognition.ai/session/loadPage` request. `null` when the dense tail
already reached the start of history.

**replayFilterVersion** `undefined | string` *required*

Fingerprint of the replayable predicate the ordinals are computed over.

**totalCount** `undefined | number` *required*

Total replayable-event count, over the same predicate as the ordinals.


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