## Compatibility
The whole hunk
from line 2, old and new numbered
/
lines
from line 2
22title: Cache diagnostics
33url: https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics
44description: Diagnose unexpected prompt cache misses by comparing consecutive requests and identifying exactly where the prompt prefix diverged.
5featureMetadata:
6 status: beta
7 betaHeader: cache-diagnosis-2026-04-07
8 zdr:
9 eligibility: eligible
10 note: Excludes [Covered Models](https://platform.claude.com/docs/en/manage-claude/api-and-data-retention#model-specific-data-retention-requirements).
11 supportedPlatforms:
12 Claude API: beta
13 Claude Platform on AWS: not available
14 Amazon Bedrock: not available
15 Google Cloud: not available
16 Microsoft Foundry: not available
517---
6
7## Compatibility
8- Status: Beta
9- [Beta header](https://platform.claude.com/docs/en/api/beta-headers): `cache-diagnosis-2026-04-07`
10- [ZDR](https://platform.claude.com/docs/en/manage-claude/api-and-data-retention): eligible (excludes [Covered Models](https://platform.claude.com/docs/en/manage-claude/api-and-data-retention#model-specific-data-retention-requirements))
11- Platforms: Claude API (beta); not available on Claude Platform on AWS, Amazon Bedrock, Google Cloud, Microsoft Foundry
1218
1319[Prompt caching](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) cuts latency and cost significantly, but only when the beginning of your prompt is byte-for-byte identical to a recent request. A reordered tool, a timestamp interpolated into your system prompt, or an edit to an earlier message can silently invalidate the cache. Without cache diagnostics, the only signal is `usage.cache_read_input_tokens` dropping to zero, with no indication of what changed.
1420