Interface: FoldedSpan

Defined in: src/core/agent/window/types.ts:232

One fold, as it survives the process: the summary's fingerprint, what it stands for, and — under retain: 'conversation' — the messages themselves.

These accumulate on the conversation checkpoint across every turn and every restart, so a standing agent that folded week one in April can still produce week one in July.

Joining a span to its summary

By CONTENT FINGERPRINT, never by index: a later fold can swallow an earlier summary, and every index in the window moves when it does. foldedSpanFor does the join for you.

Properties

foldedAtMs

readonly foldedAtMs: number

Defined in: src/core/agent/window/types.ts:252

Wall clock of the fold.

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iteration

readonly iteration: number

Defined in: src/core/agent/window/types.ts:250

ReAct iteration the fold happened at, in that run.

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messageCount

readonly messageCount: number

Defined in: src/core/agent/window/types.ts:256

How many messages the summary stands for. Always recorded, both policies.

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messages?

readonly optional messages?: readonly LLMMessage[]

Defined in: src/core/agent/window/types.ts:268

The folded messages, verbatim and in order. Present exactly when retained is 'conversation'.

Absent under 'discard' — and absent is the honest shape there, rather than an empty array that reads like "there were none".

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model

readonly model: string

Defined in: src/core/agent/window/types.ts:254

The model that wrote the summary — a claim's author is part of the claim.

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removedStageIds

readonly removedStageIds: readonly string[]

Defined in: src/core/agent/window/types.ts:258

runtimeStageIds of the stages that appended those messages.

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retained

readonly retained: CompactionRetention

Defined in: src/core/agent/window/types.ts:260

Which policy this fold ran under.

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runId

readonly runId: string

Defined in: src/core/agent/window/types.ts:248

The run whose commit log held these messages. Diagnostic, and the honest answer to "where else could I have found this?" — that log is gone with the process, which is why the messages are here.

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summaryFingerprint

readonly summaryFingerprint: string

Defined in: src/core/agent/window/types.ts:242

Fingerprint of the summary message this span was folded into — the join key back to the message sitting in history.

It is a hash of the message's full content (authored frame included), so it costs no extra bytes on the wire and cannot be forged by a summary that merely copies the frame's opening words: different content, different fingerprint, no match.