anthropic Claude Platform Release Notes ·

Claude API Refines Cache Diagnostics Fingerprint Storage

aipreviewengineer
feature

The Claude API has updated its cache diagnostics, now storing a request's fingerprint only when the `diagnostics` object is explicitly included. Requests using only the `cache-diagnosis-2026-04-07` beta header will no longer store a fingerprint, leading to `previous_message_not_found` errors if referenced later. Developers using cache diagnostics are advised to include the `diagnostics` object on every turn, setting `"previous_message_id": null` for the first request. This change aims to provide more precise control over cache diagnosis data.

Enhancements (1) ›
  • Cache Diagnostics Require Explicit `diagnostics` Object for Fingerprint Storage

    The Claude API now stores a request's fingerprint for cache diagnostics exclusively when the `diagnostics` object is present in the request. If only the `cache-diagnosis-2026-04-07` beta header is sent, the request is still accepted, but no fingerprint will be stored, resulting in `previous_message_not_found` for subsequent turns referencing it. Users should include the `diagnostics` object on every API turn, with `"previous_message_id": null` for the initial request, to ensure proper fingerprint storage and message tracking.

Read the original announcement →

https://platform.claude.com/docs/en/release-notes/overview

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