---
title: Claude Fable 5.1
url: https://platform.claude.com/docs/zh-TW/models/fable-5-1/overview
description: Claude Fable 5.1 一覽：用途、各平台上的模型 ID、上下文視窗、輸出限制、定價、可用性，以及使用它進行建構的相關資源。
---
**Latest.** Released September 1, 2026.
For demanding reasoning and long-horizon agentic work
Model ID: `claude-fable-5-1`
Context window: 1M tokens · Max output: 128K tokens · Input pricing: $10 / MTok · Output pricing: $50 / MTok
[Announcement](https://www.anthropic.com/claude-fable-and-mythos-5-1) · [What’s new](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1) · [Migration guide](https://platform.claude.com/docs/zh-TW/models/fable-5-1/migration-guide)
## 概覽
Claude Fable 5.1 延續 Claude Fable 5，輸入與輸出價格相同，快取讀取成本則降為四分之一，並在長時間執行的代理式程式開發、多步驟研究，以及文件、試算表與投影片工作方面表現更強。對於大多數工作負載，請從 Claude Opus 5.5 開始（請參閱[選擇模型](https://platform.claude.com/docs/zh-TW/about-claude/models/choosing-a-model)）。若您需要處理高難度推理與長時程代理式工作，或您在 Claude Opus 5.5 上以較高 effort 執行的評估仍未達標，請使用 Claude Fable 5.1。Claude Mythos 5.1 提供相同的能力，但僅開放給通過 Anthropic 驗證計畫（例如 [Cyber Verification Program](https://support.claude.com/en/articles/14604842)）驗證的組織。
如果您已在呼叫 Claude Fable 5，有三項變更屬於重大變更：[強制工具使用會回傳錯誤](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#forced-tool-use-is-not-supported)、[只有 Claude Fable 5.1 與 Claude Mythos 5.1 能讀取 Claude Fable 5.1 的思考區塊](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#thinking-blocks-are-tied-to-the-model-that-produced-them)，以及[編輯較早的輪次會使 thinking 區塊失效](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#editing-earlier-turns-invalidates-thinking-blocks)。另有五項為新增功能：[逐訊息 effort](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#change-effort-mid-conversation-beta)（beta）、[輪次範圍的系統訊息](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#turn-scoped-system-messages-beta)（beta）、[工具呼叫之間可讀的進度更新](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#progress-updates-between-tool-calls-beta)（`display: "updates"`，beta）、[更低的快取讀取價格](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#pricing)，以及[內容來源標記](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1#content-provenance)。
[Claude Fable 5.1 的新功能](https://platform.claude.com/docs/zh-TW/models/fable-5-1/whats-new-fable-5-1)
## Claude Fable 5.1 與 Claude Mythos 5.1
[Claude Mythos 5.1](https://platform.claude.com/docs/zh-TW/models/mythos-5-1/overview) 提供相同的功能，但僅限於透過 Anthropic 驗證計畫（例如 [Cyber Verification Program](https://support.claude.com/en/articles/14604842)）驗證的組織使用。它與 Claude Fable 5.1 共用相同的規格與定價。若要申請存取權限，請申請涵蓋您使用案例的計畫，或聯繫您的 Anthropic、AWS 或 Google Cloud 客戶團隊。
## 比較
| Model | Context | Max output | Price / MTok | Latency | Thinking | Default effort | Knowledge cutoff |
| :------------------------------------------------------------------------------------- | :------ | :--------- | :----------------- | :------- | :------------------- | :------------- | :--------------- |
| **Claude Fable 5.1** (this model) | 1M | 128K | $10 / $50 | Slower | Adaptive (always on) | `high` | Jun 2026 |
| [Claude Opus 5.5](https://platform.claude.com/docs/zh-TW/models/opus-5-5/overview) | 1M | 128K | $4 / $20 | Moderate | Adaptive (always on) | `medium` | Jun 2026 |
| [Claude Sonnet 5.5](https://platform.claude.com/docs/zh-TW/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Fast | Adaptive | `high` | Jun 2026 |
| [Claude Haiku 5.5](https://platform.claude.com/docs/zh-TW/models/haiku-5-5/overview) | 1M | 128K | From $0.10 / $0.50 | Fastest | Adaptive | `medium` | Jun 2026 |
* **Context:** 1M tokens is roughly 555k words or 2.5M Unicode characters on the current tokenizer (introduced with Claude Opus 4.7); models before it fit about 750k words in 1M tokens. 200k tokens is roughly 150k words.
* **Max output:** Synchronous Messages API limit. On the Message Batches API, Claude Opus 5.5, Claude Opus 5, Claude Sonnet 5.5, Claude Sonnet 5, Claude Haiku 5.5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, and Claude Sonnet 4.6 support up to 300k output tokens with the output-300k-2026-03-24 beta header.
* **Price / MTok:** Input / output, base price per million tokens. Batch API requests are 50% off; prompt caching reads cost 10% of the base input price (2.5% on Claude Fable 5.1 and Claude Mythos 5.1, 5% on Claude Opus 5.5 and Claude Sonnet 5.5). See Pricing for the full list.
* **Latency:** Comparative latency, relative to the current lineup, as published in the models overview. Actual latency depends on prompt length, output length, and thinking effort.
* **Thinking:** Adaptive thinking lets the model decide how much to think, steered by effort. Extended thinking is the manual budget\_tokens mode on earlier models.
* **Default effort:** The effort parameter’s default on the Claude API. Models without a value don’t support the parameter.
* **Knowledge cutoff:** Reliable knowledge cutoff: the date through which the model’s knowledge is most extensive and reliable.
## 規格
### Model IDs
| Platform | Model ID |
| :-------------------------------------------------------------------------------------------------------- | :--------------------------- |
| Claude API | `claude-fable-5-1` |
| [Amazon Bedrock](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-in-amazon-bedrock) | `anthropic.claude-fable-5-1` |
| [Google Cloud](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-on-vertex-ai) | `claude-fable-5-1` |
| [Microsoft Foundry](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-in-microsoft-foundry) | `claude-fable-5-1` |
| [Claude Platform on AWS](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-platform-on-aws) | `claude-fable-5-1` |
### Pricing
| Feature | Value |
| :---------------------------------------------------------------------------------------- | :------------------------------- |
| Input | $10 / MTok |
| Output | $50 / MTok |
| [5m cache write](https://platform.claude.com/docs/zh-TW/build-with-claude/prompt-caching) | $12.50 / MTok |
| [1h cache write](https://platform.claude.com/docs/zh-TW/build-with-claude/prompt-caching) | $20 / MTok |
| [Cache read](https://platform.claude.com/docs/zh-TW/build-with-claude/prompt-caching) | $0.25 / MTok |
| [Batch API](https://platform.claude.com/docs/zh-TW/build-with-claude/batch-processing) | 50% discount on input and output |
[Full price list](https://platform.claude.com/docs/zh-TW/about-claude/pricing)
### Capabilities
| Feature | Value |
| :----------------------------------------------------------------------------------------- | :--------------------- |
| [Context window](https://platform.claude.com/docs/zh-TW/build-with-claude/context-windows) | 1M tokens |
| Max output | 128K tokens |
| [Thinking](https://platform.claude.com/docs/zh-TW/build-with-claude/thinking) | Adaptive (always on) |
| [Default effort](https://platform.claude.com/docs/zh-TW/build-with-claude/effort) | `high` |
| Comparative latency | Slower |
| Input → output | Text and images → text |
| Reliable knowledge cutoff | Jun 2026 |
| Training data cutoff | Jun 2026 |
### Availability
| Feature | Value |
| :------------------------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [Status](https://platform.claude.com/docs/zh-TW/about-claude/model-deprecations) | Active (latest) |
| Released | September 1, 2026 |
| Retirement | Not sooner than September 1, 2027 |
| Platforms | Claude API, [Amazon Bedrock](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-in-amazon-bedrock), [Google Cloud](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-on-vertex-ai), [Microsoft Foundry](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-in-microsoft-foundry), [Claude Platform on AWS](https://platform.claude.com/docs/zh-TW/build-with-claude/claude-platform-on-aws) |
## 資源
針對長時程與代理式工作的模型專屬提示指引。
從 Claude Fable 5、Claude Opus 5 或 Claude Opus 4.8 遷移時會有哪些變化。
此模型的思考區塊何時仍可使用：跨模型切換以及跨對話變更時。
在對話進行中變更 effort 等級，而不會使提示快取失效。
處理分類器拒絕，並在另一個 Claude 模型上重試。
Claude Fable 5.1 上唯一的思考模式。使用 `effort` 控制深度。
## 參考資料
Claude Fable 5.1 在 claude.ai 與 Claude 應用程式上使用的系統提示。
Claude Fable 5.1 與 Claude Mythos 5.1 的安全評估與部署決策。
完整價格表，包含批次折扣與提示快取費率。
模型 ID、別名與固定快照的運作方式。
每個 Claude 模型的生命週期狀態與退役承諾。