Observed source change · Anthropic
Claude prompt cache policy and minimums documentation changed
Published documentation; runtime behavior and legal interpretation not established.
Last unchanged check: 2026-10-22T21:55:09Z
First changed check: 2026-10-23T00:00:11Z
Before
model: 'claude-opus-5-5', system: "You are an AI assistant tasked with analyzing literary works. Your goal is to provide insightful commentary on themes, characters, and writing style.", model: 'claude-opus-5-5', Shorter prompts cannot be cached, even if marked with `cache_control`. Any requests to cache fewer than this number of tokens are processed without caching, and no error is returned. To verify whether a prompt was cached, check the [response usage fields](https://platform.claude.com/docs/en/build-with-claude/prompt-caching#tracking-cache-performance): if both `cache_creation_input_tokens` and `cache_read_input_tokens` are 0, the prompt was not cached (likely because it did not meet the minimum length …
After
use Anthropic\Messages\Model; model: Model::CLAUDE_OPUS_5_5, system: 'You are an AI assistant tasked with analyzing literary works. Your goal is to provide insightful commentary on themes, characters, and writing style.', use Anthropic\Messages\Model; model: Model::CLAUDE_OPUS_5_5, Shorter prompts cannot be cached, even if marked with `cache_control`. Any requests to cache fewer than this number of tokens are processed without caching, and no error is returned. To check whether a prompt was cached, look at the [response usage fields](https://platform.claude.com/docs/en/build-with-claude/prompt-caching#tracking-cache-performance): if both `cache_creation_input_tokens` and `cache_read_input_tokens` are 0, the prompt was not cached (likely because it did …
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Raw before SHA-256: fab7f318164b6e19fc99076258b1007b2b67b56892a5e766b62f218294f87297
Raw after SHA-256: b3ab07efdbef9f4cce1cdfdd27a51e88384c3315eae56ef528e3577854263e3e
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