fast-mode changedbuild-with-claude/fast-mode
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88 eligibility: eligible
99 note: Excludes [Covered Models](https://platform.claude.com/docs/en/manage-claude/api-and-data-retention#model-specific-data-retention-requirements). Same Messages API endpoint with faster inference. ZDR applies regardless of speed setting.
1010 supportedModels:
11 - claude-fable-5-2
12 - claude-mythos-5-2
1113 - claude-opus-5-5
1214 - claude-opus-5
1315 - claude-opus-4-8
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1416 supportedPlatforms:
1517 Claude API: stable
1618 Claude Models on Google Cloud (Anthropic managed): stable
19 Claude Models on Google Cloud (Google managed): stable
1720 Microsoft Foundry (hosted on Azure):
1821 availability: stable
1922 note: On Microsoft Foundry, fast mode is a separate model whose ID ends in `-fast`. Send requests to a deployment of that model, and leave out `speed`.
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2629* **Messages API**: Set `speed: "fast"` on the request.
2730* **Managed Agents**: Set `speed` on the agent’s model object, for example `{"id": "claude-opus-5-5", "speed": "fast"}`.
2831
29Fast mode delivers up to 2.5x higher output tokens per second at premium pricing. Set `speed: "fast"` on your request to opt in. Fast mode is available on Claude Opus 5.5. Fast mode for Claude Opus 5 and Claude Opus 4.8 is in research preview.
32Fast mode delivers up to 2.5x higher output tokens per second at premium pricing. Set `speed: "fast"` on your request to opt in. Fast mode is available on Claude Fable 5.2 and Claude Opus 5.5. Fast mode for Claude Opus 5 and Claude Opus 4.8 is in research preview. Claude Mythos 5.2 supports fast mode too.
3033
3134## How fast mode works
3235
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202205
203206## Rate limits
204207
205Fast mode has a dedicated rate limit that is separate from standard rate limits. When you exceed your fast mode rate limit, the API returns a `429` error with a `retry-after` header that says when capacity is available.
208Fast mode has a dedicated rate limit that is separate from standard rate limits. When you exceed your fast mode rate limit, the API returns a `429` error with a `retry-after` header that says when capacity is available. On [Claude Models on Google Cloud (Google managed)](https://platform.claude.com/docs/en/build-with-claude/claude-models-on-google-cloud/google-managed#rate-limits), Google Cloud manages rate limits and quotas.
206209
207Claude Opus 5.5 has a default fast mode rate limit in the Start, Build, and Scale [usage tiers](https://platform.claude.com/docs/en/api/rate-limits), so you don’t need to request access to use fast mode with it. Organizations in the Evaluation tier can use fast mode with Claude Opus 5.5 once they move to the Start, Build, or Scale tier.
210Claude Opus 5.5 has a default fast mode rate limit in the Start, Build, and Scale [usage tiers](https://platform.claude.com/docs/en/api/rate-limits), so you don’t need to request access to use fast mode with it. Organizations in the Evaluation tier can use fast mode with Claude Opus 5.5 once they move to the Start, Build, or Scale tier. The same applies to Claude Fable 5.2. It also applies to Claude Mythos 5.2.
208211
209212The response includes headers that indicate your fast mode rate limit status:
210213
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671674
672675## Pricing
673676
674Fast mode is priced at a multiplier on standard rates across the full context window, including requests over 200k input tokens.
677Fast mode is priced at a multiplier on standard rates across the full context window, including requests over 200k input tokens. On Claude Models on Google Cloud (Google managed), Google Cloud sets fast mode prices. See [Cloud platform pricing](https://platform.claude.com/docs/en/about-claude/pricing#cloud-platform-pricing).
675678
676679| Model | Input | Output |
677680| ------------------------------- | -------------- | -------------- |
681| Claude Fable 5.2 | $16 USD / MTok | $80 USD / MTok |
682| Claude Mythos 5.2 | $16 USD / MTok | $80 USD / MTok |
678683| Claude Opus 5.5 | $8 USD / MTok | $40 USD / MTok |
679684| Claude Opus 5 / Claude Opus 4.8 | $10 USD / MTok | $50 USD / MTok |
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704709* Availability: Available
705710* Usage: Set `speed: "fast"` on the request.
706711
707| Status | Cloud platforms | Models |
708| --------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
709| Available | Claude API, [Claude Models on Google Cloud (Anthropic managed)](https://platform.claude.com/docs/en/build-with-claude/claude-models-on-google-cloud/anthropic-managed) | [Claude Opus 5.5](https://platform.claude.com/docs/en/models/opus-5-5/overview) |
710| Available<sup>1</sup> | [Microsoft Foundry (hosted on Azure)](https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry) | [Claude Opus 5.5](https://platform.claude.com/docs/en/models/opus-5-5/overview) |
711| Research preview | Claude API | [Claude Opus 5](https://platform.claude.com/docs/en/models/opus-5/overview), [Claude Opus 4.8](https://platform.claude.com/docs/en/models/opus-4-8/overview) |
712| Status | Cloud platforms | Models |
713| --------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
714| Available | Claude API, [Claude Models on Google Cloud (Anthropic managed)](https://platform.claude.com/docs/en/build-with-claude/claude-models-on-google-cloud/anthropic-managed), [Claude Models on Google Cloud (Google managed)](https://platform.claude.com/docs/en/build-with-claude/claude-models-on-google-cloud/google-managed) | [Claude Fable 5.2](https://platform.claude.com/docs/en/models/fable-5-2/overview), [Claude Mythos 5.2](https://platform.claude.com/docs/en/models/mythos-5-2/overview) |
715| Available | Claude API, [Claude Models on Google Cloud (Anthropic managed)](https://platform.claude.com/docs/en/build-with-claude/claude-models-on-google-cloud/anthropic-managed) | [Claude Opus 5.5](https://platform.claude.com/docs/en/models/opus-5-5/overview) |
716| Available<sup>1</sup> | [Microsoft Foundry (hosted on Azure)](https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry) | [Claude Opus 5.5](https://platform.claude.com/docs/en/models/opus-5-5/overview) |
717| Research preview | Claude API | [Claude Opus 5](https://platform.claude.com/docs/en/models/opus-5/overview), [Claude Opus 4.8](https://platform.claude.com/docs/en/models/opus-4-8/overview) |
712718
7137191. On Microsoft Foundry, fast mode is a separate model whose ID ends in `-fast`. Send requests to a deployment of that model, and leave out `speed`.
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