Request 2 caches its request content (not the response) changedbuild-with-claude/prompt-caching
Nearest release: v2.1.292, published 11 hours 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+4added
Lines−4removed
From line
234
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits19to this page, all time
The whole hunk
from line 234, old and new numbered
/
from line 234
234234| Model | Base input tokens | 5m cache writes | 1h cache writes | Cache hits and refreshes | Output tokens |
235235| :------------------------------------------------------------------------------------------------------------------------------------ | :---------------- | :-------------- | :-------------- | :----------------------- | :------------ |
236236| Claude Fable 5.1 | $10 / MTok | $12.50 / MTok | $20 / MTok | $0.25 / MTok<sup>1</sup> | $50 / MTok |
237| Claude Mythos 5.1 ([limited availability](https://anthropic.com/glasswing)) | $10 / MTok | $12.50 / MTok | $20 / MTok | $0.25 / MTok<sup>1</sup> | $50 / MTok |
237| Claude Mythos 5.1 ([limited availability](https://support.claude.com/en/articles/14604842)) | $10 / MTok | $12.50 / MTok | $20 / MTok | $0.25 / MTok<sup>1</sup> | $50 / MTok |
238238| Claude Fable 5 | $10 / MTok | $12.50 / MTok | $20 / MTok | $1 / MTok | $50 / MTok |
239| Claude Mythos 5 ([limited availability](https://anthropic.com/glasswing)) | $10 / MTok | $12.50 / MTok | $20 / MTok | $1 / MTok | $50 / MTok |
239| Claude Mythos 5 ([limited availability](https://support.claude.com/en/articles/14604842)) | $10 / MTok | $12.50 / MTok | $20 / MTok | $1 / MTok | $50 / MTok |
240240| Claude Opus 5.5 | $4 / MTok | $5 / MTok | $8 / MTok | $0.20 / MTok<sup>2</sup> | $20 / MTok |
241241| Claude Opus 5 | $5 / MTok | $6.25 / MTok | $10 / MTok | $0.50 / MTok | $25 / MTok |
242242| Claude Opus 4.8 | $5 / MTok | $6.25 / MTok | $10 / MTok | $0.50 / MTok | $25 / MTok |
from line 603
603603
604604On the Claude API, [Claude Platform on AWS](https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws), [Google Cloud](https://platform.claude.com/docs/en/build-with-claude/claude-on-vertex-ai), and [Microsoft Foundry](https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry), the minimum cacheable prompt length is:
605605
606* 512 tokens for Claude Fable 5.1, Claude Mythos 5.1, Claude Opus 5.5, Claude Opus 5, Claude Sonnet 5.5, Claude Fable 5, and [Claude Mythos 5](https://anthropic.com/glasswing)
606* 512 tokens for Claude Fable 5.1, [Claude Mythos 5.1](https://platform.claude.com/docs/en/models/mythos-5-1/overview), Claude Opus 5.5, Claude Opus 5, Claude Sonnet 5.5, Claude Fable 5, and [Claude Mythos 5](https://platform.claude.com/docs/en/models/mythos-5/overview)
607607* 2,048 tokens for [Claude Mythos Preview](https://anthropic.com/glasswing) and Claude Opus 4.7
608608* 4,096 tokens for Claude Opus 4.6 and Claude Opus 4.5
609609* 1,024 tokens for Claude Opus 4.8, Claude Sonnet 5, Claude Sonnet 4.6, Claude Sonnet 4.5, Claude Opus 4.1 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)), Claude Opus 4 ([retired, except on Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations)), and Claude Sonnet 4 ([retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-claude/model-deprecations))
from line 672
672672On models that support [mid-conversation tool changes](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages#mid-conversation-tool-changes), the `inline-tools-2026-09-15` beta header lets you add a tool, or change a tool's definition, partway through a conversation without editing `tools`. Send the definition in a `tool_addition` block in a mid-conversation system message and leave `tools` exactly as you first sent it. The cached prefix still matches, so only the appended message is processed as new input. The one exception is a `tools` array with no non-deferred tool, where the first tool defined this way costs one full cache miss on that request. See [Define tools in a message](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages#define-tools-in-a-message-beta).
673673
674674<Note>
675 On Claude Fable 5.1, Claude Mythos 5.1, Claude Fable 5, [Claude Mythos 5](https://anthropic.com/glasswing), Claude Opus 5.5, Claude Opus 4.8, Claude Opus 5, and Claude Sonnet 5.5, you can add a new system instruction partway through a conversation without invalidating the system or message caches. Append a `{"role": "system"}` message to `messages` instead of editing the top-level `system` field, so the cached prefix stays unchanged. This feature is not available on Claude Sonnet 5. Use the top-level `system` field instead. See [Mid-conversation system messages](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages).
675 On Claude Fable 5.1, [Claude Mythos 5.1](https://platform.claude.com/docs/en/models/mythos-5-1/overview), Claude Fable 5, [Claude Mythos 5](https://platform.claude.com/docs/en/models/mythos-5/overview), Claude Opus 5.5, Claude Opus 4.8, Claude Opus 5, and Claude Sonnet 5.5, you can add a new system instruction partway through a conversation without invalidating the system or message caches. Append a `{"role": "system"}` message to `messages` instead of editing the top-level `system` field, so the cached prefix stays unchanged. This feature is not available on Claude Sonnet 5. Use the top-level `system` field instead. See [Mid-conversation system messages](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages).
676676</Note>
677677
678678### Tracking cache performance
No line in this hunk matches that.