99 pages for claude-fable-5.

Create a Message Batch Claude Developer Platform · in the page api/messages/batches/create …onnet-5-5"` Efficient model for coding and agents - `"claude-fable-5-1"` Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflow… Retrieve Message Batch results Claude Developer Platform · in the page api/messages/batches/results …5"` Efficient model for coding and agents - `"claude-fable-5-1"` Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise work… Count tokens in a Message Claude Developer Platform · in the page api/messages/count_tokens …claude-sonnet-5-5"` Efficient model for coding and agents - `"claude-fable-5-1"` Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows… Create a Message Claude Developer Platform · in the page api/messages/create …claude-sonnet-5-5"` Efficient model for coding and agents - `"claude-fable-5-1"` Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows… claude-in-amazon-bedrock Claude Developer Platform · in the page build-with-claude/claude-in-amazon-bedrock …| `anthropic.claude-fable-5-1` | Open | | C… claude-in-microsoft-foundry Claude Developer Platform · in the page build-with-claude/claude-in-microsoft-foundry …| `claude-fable-5-1` | | ✓ | | Claude Mythos 5.1 ([limited availability](https://support.claud… claude-on-vertex-ai Claude Developer Platform · in the page build-with-claude/claude-on-vertex-ai …| `claude-fable-5-1` | | Claude Mythos 5.1 ([limited availability](https://support.claude.com/en/articles/14604842))… claude-platform-on-aws Claude Developer Platform · in the page build-with-claude/claude-platform-on-aws …| `claude-fable-5-1` | | Claude Fable 5 | `cl… sent_count = len(messages sent in the compaction request) Claude Developer Platform · in the page build-with-claude/compaction …ion#model-specific-data-retention-requirements)) - Supported models: `claude-fable-5-1`, `claude-mythos-5-1`, `claude-fable-5`, `claude-mythos-5`, `claude-mythos-preview`, `claude-opus-5`, `claude-opu… compaction-background Claude Developer Platform · in the page build-with-claude/compaction-background …tatus: beta betaHeader: compact-2026-09-04 supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… compaction-keep-recent-turns Claude Developer Platform · in the page build-with-claude/compaction-keep-recent-turns …tatus: beta betaHeader: compact-2026-09-04 supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… compaction-on-demand Claude Developer Platform · in the page build-with-claude/compaction-on-demand …tatus: beta betaHeader: compact-2026-09-04 supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… compaction-thinking-blocks Claude Developer Platform · in the page build-with-claude/compaction-thinking-blocks …tatus: beta betaHeader: compact-2026-09-04 supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… compaction-threshold Claude Developer Platform · in the page build-with-claude/compaction-threshold …model-specific-data-retention-requirements). supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… effort Claude Developer Platform · in the page build-with-claude/effort …model-specific-data-retention-requirements). supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… fallback-credit Claude Developer Platform · in the page build-with-claude/fallback-credit …s=["fallback-credit-2026-07-01"], **body ) response = send("claude-fable-5", request) if ( response.stop_reason == "refusal" and (details := response.stop_details) and (… mid-conversation-system-messages Claude Developer Platform · in the page build-with-claude/mid-conversation-system-messages …s[6]` and `messages[7]` both render, in order. ```json { "model": "claude-fable-5-1", "max_tokens": 16000, "messages": [ { "role": "user", "content": "Fix the failing test." }, {… preserved-thinking Claude Developer Platform · in the page build-with-claude/preserved-thinking …\ -H "content-type: application/json" \ -d '{ "model": "claude-fable-5-1", "max_tokens": 16000, "thinking": { "type": "adaptive", "block_binding": {… claude-prompting-best-practices Claude Developer Platform · in the page build-with-claude/prompt-engineering/claude-prompting-best-practices …orm.claude.com/docs/en/build-with-claude/prompt-engineering/prompting-claude-fable-5-1) | Differences from Claude Fable 5: effort levels, finishing long tasks, user-facing progress updates, passing… refusals-and-fallback Claude Developer Platform · in the page build-with-claude/refusals-and-fallback …\ -H "content-type: application/json" \ -d '{ "model": "claude-fable-5", "max_tokens": 1024, "fallbacks": "default", "messages": [{"role": "user", "content": "Hello, Cl… structured-outputs Claude Developer Platform · in the page build-with-claude/structured-outputs …model-specific-data-retention-requirements). supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-mythos-preview - claude-opus-… task-budgets Claude Developer Platform · in the page build-with-claude/task-budgets …: beta betaHeader: task-budgets-2026-03-13 supportedModels: - claude-fable-5-1 - claude-mythos-5-1 - claude-fable-5 - claude-mythos-5 - claude-opus-5-5 - claude-opus-5… thinking Claude Developer Platform · in the page build-with-claude/thinking …_request_error` as an unknown `display` value. ```json { "model": "claude-fable-5-1", "max_tokens": 16000, "thinking": { "type": "adaptive", "display": "updates" }, "tools": [ { "na… token-counting Claude Developer Platform · in the page build-with-claude/token-counting …ount your prompts with the `model` ID you plan to use (for example, `"claude-fable-5-1"`). </Note> *** ## Pricing and rate limits Token counting is **free to use** but subject to requests per minut… API usage primer for Claude Claude Developer Platform · in the page claude_api_primer …nd research tasks, at 2.5x Claude Opus 5.5 pricing: Claude Fable 5.1: claude-fable-5-1 Previous Opus model: Claude Opus 5: claude-opus-5 Smart model: Claude Sonnet 5.5: claude-sonnet-5-5 Previous Sonn… home Claude Developer Platform · in the page home …5.1](https://platform.claude.com/docs/en/models/fable-5-1/overview) (`claude-fable-5-1`) — New — *For demanding reasoning and long-horizon agentic work* — Most capable · Research · Multi-day tasks… intro Claude Developer Platform · in the page intro …5.1](https://platform.claude.com/docs/en/models/fable-5-1/overview) (`claude-fable-5-1`) — New — *For demanding reasoning and long-horizon agentic work* — Most capable · Research · Multi-day tasks * [… dreams Claude Developer Platform · in the page managed-agents/dreams …e dreaming pipeline. During the research preview, `claude-opus-5-5`, `claude-fable-5-1`, `claude-opus-5`, `claude-fable-5`, `claude-opus-4-8`, `claude-opus-4-7`, `claude-sonnet-5-5`, `claude-sonnet-5`… Or, for Claude Mythos 5.1, which offers the same capabilities to verified organizations: Claude Developer Platform · in the page models/fable-5-1/migration-guide …te your code for you ```text /claude-api migrate this project to claude-fable-5-1 ``` The skill applies the model ID swap and, as needed, breaking parameter changes, prefill replacement, and… overview Claude Developer Platform · in the page models/fable-5-1/overview …6. 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 [… whats-new-fable-5-1 Claude Developer Platform · in the page models/fable-5-1/whats-new-fable-5-1 …--------------------------------------------- | | Claude Fable 5.1 | claude-fable-5-1 | Successor to Claude Fable 5, for long-running agentic coding, knowledge work, and research | All customers, on… overview Claude Developer Platform · in the page models/fable-5/overview …rm.claude.com/docs/en/models/fable-5-1/migration-guide#migrating-from-claude-fable-5-to-claude-fable-5-1) Model ID: `claude-fable-5` Context window: 1M tokens · Max output: 128K tokens · Input prici… overview Claude Developer Platform · in the page models/mythos-5-1/overview …<Card title="System card" icon="file" href="https://www.anthropic.com/claude-fable-5-1-mythos-5-1-system-card"> Safety evaluations and deployment decisions for Claude Fable 5.1 and Claude Mythos 5… overview Claude Developer Platform · in the page models/mythos-5/overview …ut pricing: $50 / MTok [Announcement](https://www.anthropic.com/news/claude-fable-5-mythos-5) · [Migration guide](https://platform.claude.com/docs/en/models/fable-5-1/migration-guide#migrating-from-c… Models overview Claude Developer Platform · in the page models/overview …| `claude-fable-5-1` | `claude-opus-5-5`… overview Claude Developer Platform · in the page release-notes/overview …ader. ### September 1, 2026 * We've launched **Claude Fable 5.1** (`claude-fable-5-1`), the successor to Claude Fable 5 for long-running agentic coding, knowledge work, and research, alongside **Cla… claude-haiku-4-5 Claude Developer Platform · in the page release-notes/system-prompts/claude-haiku-4-5 …nnet 5.5, Claude Haiku 5.5, and Claude Haiku 4.5, with model strings 'claude-fable-5-1', 'claude-opus-5-5', 'claude-sonnet-5-5', 'claude-haiku-5-5', and 'claude-haiku-4-5-20251001'. Above Opus sits A… claude-haiku-5-5 Claude Developer Platform · in the page release-notes/system-prompts/claude-haiku-5-5 …pus 5.5, Claude Sonnet 5.5, and Claude Haiku 5.5, with model strings 'claude-fable-5-1', 'claude-opus-5-5', 'claude-sonnet-5-5', and 'claude-haiku-5-5'. Above Opus sits Anthropic's new Mythos tier. T… claude-opus-5 Claude Developer Platform · in the page release-notes/system-prompts/claude-opus-5 …laude Sonnet 5, and Claude Haiku 4.5. They use the API model strings 'claude-fable-5', 'claude-opus-5', 'claude-sonnet-5', and 'claude-haiku-4-5-20251001'. Above Opus sits Anthropic's new Mythos tier… claude-opus-5-5 Claude Developer Platform · in the page release-notes/system-prompts/claude-opus-5-5 …laude Sonnet 5, and Claude Haiku 4.5. They use the API model strings 'claude-fable-5-1', 'claude-opus-5-5', 'claude-sonnet-5', and 'claude-haiku-4-5-20251001'. Above Opus sits Anthropic's new Mythos… claude-sonnet-4-6 Claude Developer Platform · in the page release-notes/system-prompts/claude-sonnet-4-6 …ude Sonnet 5.5, and Claude Haiku 5.5. They use the API model strings 'claude-fable-5-1', 'claude-opus-5-5', 'claude-sonnet-5-5', and 'claude-haiku-5-5'. Claude Sonnet 4.6 (this model, 'claude-sonnet-4… claude-sonnet-5-5 Claude Developer Platform · in the page release-notes/system-prompts/claude-sonnet-5-5 …pus 5.5, Claude Sonnet 5.5, and Claude Haiku 5.5, with model strings 'claude-fable-5-1', 'claude-opus-5-5', 'claude-sonnet-5-5', and 'claude-haiku-5-5'. Above Opus sits Anthropic's new Mythos tier. T… overview Claude Developer Platform · in the page release-notes/system-prompts/overview …docs/en/release-notes/system-prompts/claude-opus-5-5" /> <Card id="claude-fable-5-1" title="Claude Fable 5.1" icon="file" href="https://platform.claude.com/docs/en/release-notes/system-prompts/clau… overview Claude Developer Platform · in the page resources/overview …d Mythos 5.1 System Card" icon="file" href="https://www.anthropic.com/claude-fable-5-1-mythos-5-1-system-card"> Detailed documentation of Claude Fable 5.1 and Claude Mythos 5.1. </Card> <Card… Configure your agent Claude Code CLI · in the page agent-sdk/configuration …n: ```typescript TypeScript theme={null} const options = { model: "claude-fable-5", fallbackModel: "claude-opus-5,claude-sonnet-5", }; ``` ```python Python theme={null} options = ClaudeAgentOpti… Claude Code on Claude Platform on AWS Claude Code CLI · in the page claude-platform-on-aws …e at once: ```bash theme={null} export ANTHROPIC_DEFAULT_FABLE_MODEL=claude-fable-5 export ANTHROPIC_DEFAULT_OPUS_MODEL=claude-opus-4-8 export ANTHROPIC_DEFAULT_SONNET_MODEL=claude-sonnet-5 export AN… Scan your codebase for vulnerabilities Claude Code CLI · in the page claude-security …](https://platform.claude.com/docs/en/about-claude/models/introducing-claude-fable-5-and-claude-mythos-5), see the [Claude Security](https://claude.com/product/claude-security) product, available on t… Model configuration Claude Code CLI · in the page model-config …`best` resolve to Fable 5. A gateway that isn't configured to serve `claude-fable-5-1` rejects requests for that model. To use Fable 5.1 through a gateway that serves it, select it with `/model claud… Week 36 · August 31 – September 4, 2026 Claude Code CLI · in the page whats-new/2026-w36 …still selects Fable 5. If your gateway serves Fable 5.1, run `/model claude-fable-5-1`. Requires v2.1.257 or later. Switch the current session to Fable 5.1 and save it as your default: ```text Clau…