Create a Message changedapi/messages/create
Nearest release: v2.1.306, published under an hour before this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Recorded here
Lines+28added
Lines−0removed
From line
3,878
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits24to this page, all time
The whole hunk
from line 3878, old and new numbered
/
from line 3878
38783878
38793879 - `CacheMissModelChanged object`
38803880
3881 A `cache_miss_reason` for a request whose `model` or `speed` differs from the previous request's.
3882
3883 See the [cache diagnostics guide](https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics?sdk_languages=http#cache-miss-reason-types) to learn what to change for each reason.
3884
38813885 - `type: "model_changed"`
38823886
38833887 default: model_changed
from line 3892
38883892
38893893 - `CacheMissSystemChanged object`
38903894
3895 A `cache_miss_reason` for a request whose `system` differs from the previous request's.
3896
3897 See the [cache diagnostics guide](https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics?sdk_languages=http#cache-miss-reason-types) to learn what to change for each reason.
3898
38913899 - `type: "system_changed"`
38923900
38933901 default: system_changed
from line 3906
38983906
38993907 - `CacheMissToolsChanged object`
39003908
3909 A `cache_miss_reason` for a request whose `tools` differ from the previous request's, for example because tools were added, removed, or reordered.
3910
3911 See the [cache diagnostics guide](https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics?sdk_languages=http#cache-miss-reason-types) to learn what to change for each reason.
3912
39013913 - `type: "tools_changed"`
39023914
39033915 default: tools_changed
from line 3920
39083920
39093921 - `CacheMissMessagesChanged object`
39103922
3923 A `cache_miss_reason` for a request whose `messages` differ from the previous request's in an earlier entry, instead of only having entries appended. The `model`, `system`, and `tools` match.
3924
3925 See the [cache diagnostics guide](https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics?sdk_languages=http#cache-miss-reason-types) to learn what to change for each reason.
3926
39113927 - `type: "messages_changed"`
39123928
39133929 default: messages_changed
from line 3934
39183934
39193935 - `CacheMissPreviousMessageNotFound object`
39203936
3937 A `cache_miss_reason` for when the API doesn't have a stored record of the request that `diagnostics.previous_message_id` references.
3938
3939 This doesn't mean that this request changed.
3940
3941 See the [cache diagnostics guide](https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics?sdk_languages=http#cache-miss-reason-types) to learn what to change for each reason.
3942
39213943 - `type: "previous_message_not_found"`
39223944
39233945 default: previous_message_not_found
39243946
39253947 - `CacheMissUnavailable object`
3948
3949 A `cache_miss_reason` for when the API can't give a diagnosis. The request itself was processed normally.
3950
3951 This includes a request whose `model`, `system`, and `tools` match the previous request's but whose other prompt-affecting parameters, such as `thinking` or `tool_choice`, differ.
3952
3953 See the [cache diagnostics guide](https://platform.claude.com/docs/en/build-with-claude/cache-diagnostics?sdk_languages=http#cache-miss-reason-types) to learn what to change for each reason.
39263954
39273955 - `type: "unavailable"`
39283956
No line in this hunk matches that.