One of the following:

class CacheMiss { cache_missed_tokens, reason, type, comparison_reusable_tokens }

cache_missed_tokens: Integer

The estimated number of input tokens affected after the first detected divergence.

reason: :model_changed | :prompt_cache_key_changed | :tools_changed | 6 more

The reason prompt cache reuse did not occur.

One of the following:

:model_changed

:prompt_cache_key_changed

:tools_changed

:text_format_changed

:reasoning_effort_changed

:verbosity_changed

:context_compacted

:input_changed

:service_tier_changed

type: :cache_miss

comparison_reusable_tokens: Integer

The raw token count of the reusable prefix in the compared response.

class CacheHit { type }

type: :cache_hit

class ComparisonResponseNotFound { type }

type: :comparison_response_not_found

class Unavailable { type }

type: :unavailable