Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.267 ·

Reactive compaction telemetry gains error-kind and cache-cold fields

Reactive compaction now reports a structured error kind and whether the prompt cache was cold when it ran

TierUnder the hoodhow much it should matter to you
Useful1my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaCompactionwhat it touches
KindInternal Changesin v2.1.267,
Group of 2 Under the hood

Reactive compaction now reports a structured error kind and whether the prompt cache was cold when it ran

What

  • Reactive-compaction failure results now include a structured errorKind field (thrown, no_assistant_message, empty_summary, or the API's own error tag) alongside the existing free-text detail.
  • The reactive-compaction telemetry event now also reports cacheCold (whether the prompt cache was cold) and a status field, threaded through as a new cacheCold option.

Why

This makes it easier to tell why an automatic (reactive) compaction attempt failed and whether a cold prompt cache played a role, improving diagnosis of compaction issues.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtThe `tengu_reactive_compact_failed` gate hasn't been read for this site's account, so nothing can be said about whether it's active here.

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