19 ファイル変更+117-98
この更新の概要
新モデルClaude Opus 5の導入に伴い、各プラットフォームでのデフォルトモデルがOpus 4.8からOpus 5へ引き上げられました。特定のコンテンツ検知時に別のモデルへ自動移行するフォールバック機能が強化され、Opus 5におけるサイバーセキュリティや生物学関連の判定ルールが詳細化されています。あわせて、Google Cloud Vertex AI向けの新しい環境変数の追加や、各クラウドプロバイダーにおけるモデルIDの解決ルールの更新が行われました。
@@ -11,7 +11,7 @@ Claude is a family of state-of-the-art large language models developed by Anthro
## Choosing a model
If you're unsure which model to use, start with **Claude Opus 4.8** for complex agentic coding and enterprise work. For workloads that need the highest available capability, use [Claude Fable 5](#claude-fable-5-and-claude-mythos-5).
If you're unsure which model to use, start with **Claude Opus 5** for complex agentic coding and enterprise work. For workloads that need the highest available capability, use [Claude Fable 5](#claude-fable-5-and-claude-mythos-5).
All current Claude models support text and image input, text output, multilingual capabilities, and vision. Models are available through the Claude API, [Amazon Bedrock](/docs/en/build-with-claude/claude-in-amazon-bedrock), [Claude Platform on AWS](/docs/en/build-with-claude/claude-platform-on-aws), [Google Cloud](/docs/en/build-with-claude/claude-on-vertex-ai), and [Microsoft Foundry](/docs/en/build-with-claude/claude-in-microsoft-foundry).
@@ -25,29 +25,29 @@ Claude Fable 5 is generally available on the Claude API, Amazon Bedrock, Claude
### Latest models comparison
| Feature | Claude Fable 5 | Claude Opus 4.8 | Claude Sonnet 5 | Claude Haiku 4.5 |
| Feature | Claude Fable 5 | Claude Opus 5 | Claude Sonnet 5 | Claude Haiku 4.5 |
| -------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------- |
| **Description** | Next-generation intelligence for long-running agents | For complex agentic coding and enterprise work | The best combination of speed and intelligence | The fastest model with near-frontier intelligence |
| **Claude API ID** | claude-fable-5 | claude-opus-4-8 | claude-sonnet-5 | claude-haiku-4-5-20251001 |
| **Claude API alias** | claude-fable-5 | claude-opus-4-8 | claude-sonnet-5 | claude-haiku-4-5 |
| **AWS Bedrock ID** | anthropic.claude-fable-53 | anthropic.claude-opus-4-83 | anthropic.claude-sonnet-53 | anthropic.claude-haiku-4-5-20251001-v1:0 |
| **Google Cloud ID** | claude-fable-5 | claude-opus-4-8 | claude-sonnet-5 | claude-haiku-4-5\@20251001 |
| **Claude API ID** | claude-fable-5 | claude-opus-5 | claude-sonnet-5 | claude-haiku-4-5-20251001 |
| **Claude API alias** | claude-fable-5 | claude-opus-5 | claude-sonnet-5 | claude-haiku-4-5 |
| **AWS Bedrock ID** | anthropic.claude-fable-53 | anthropic.claude-opus-53 | anthropic.claude-sonnet-53 | anthropic.claude-haiku-4-5-20251001-v1:0 |
| **Google Cloud ID** | claude-fable-5 | claude-opus-5 | claude-sonnet-5 | claude-haiku-4-5\@20251001 |
| **Pricing**1 | $10 / input MTok $50 / output MTok | $5 / input MTok $25 / output MTok | $3 / input MTok $15 / output MTok4 | $1 / input MTok $5 / output MTok |
| **[Extended thinking (`thinking.type: "enabled"`)](/docs/en/build-with-claude/extended-thinking)** | No | No | No | Yes |
| **[Adaptive thinking](/docs/en/build-with-claude/thinking-steering-and-cost)** | Yes (always on) | Yes | Yes | No |
| **[Adaptive thinking](/docs/en/build-with-claude/thinking)** | Yes (always on) | Yes | Yes | No |
| **Comparative latency** | Slower | Moderate | Fast | Fastest |
| **Context window** | <Tooltip tooltipContent="~555k words \ ~2.5M unicode characters. Claude Fable 5 uses the tokenizer introduced with Claude Opus 4.7; compared to models before Claude Opus 4.7, the same text produces roughly 30% more tokens. The exact increase depends on the content.">1M tokens</Tooltip> | <Tooltip tooltipContent="~555k words \ ~2.5M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~555k words \ ~2.5M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> |
| **Max output** | 128k tokens | 128k tokens | 128k tokens | 64k tokens |
| **Reliable knowledge cutoff** | Jan 20262 | Jan 20262 | Jan 20262 | Feb 2025 |
| **Training data cutoff** | Jan 2026 | Jan 2026 | Jan 2026 | Jul 2025 |
| **Reliable knowledge cutoff** | Jan 20262 | May 20262 | Jan 20262 | Feb 2025 |
| **Training data cutoff** | Jan 2026 | May 2026 | Jan 2026 | Jul 2025 |
*1 - See [Pricing](/docs/en/about-claude/pricing) for complete pricing information including Batch API discounts and prompt caching rates.*
*1 See [Pricing](/docs/en/about-claude/pricing) for complete pricing information including Batch API discounts and prompt caching rates.*
*2 - **Reliable knowledge cutoff** indicates the date through which a model's knowledge is most extensive and reliable. **Training data cutoff** is the broader date range of training data used. For more information, see [Anthropic's Transparency Hub](https://www.anthropic.com/transparency).*
*2 **Reliable knowledge cutoff** indicates the date through which a model's knowledge is most extensive and reliable. **Training data cutoff** is the broader date range of training data used. For more information, see [Anthropic's Transparency Hub](https://www.anthropic.com/transparency).*
*3 - Claude Fable 5, Claude Opus 4.8, and Claude Sonnet 5 are available on Bedrock through [Claude in Amazon Bedrock](/docs/en/build-with-claude/claude-in-amazon-bedrock) (the Messages-API Bedrock endpoint).*
*3 Claude Fable 5, Claude Opus 5, and Claude Sonnet 5 are available on Bedrock through [Claude in Amazon Bedrock](/docs/en/build-with-claude/claude-in-amazon-bedrock) (the Messages-API Bedrock endpoint).*
*4 - Introductory pricing of $2 / $10 per MTok applies to Claude Sonnet 5 through August 31, 2026. See [Pricing](/docs/en/about-claude/pricing#claude-sonnet-5-introductory-pricing).*
*4 Introductory pricing of $2 / $10 per MTok applies to Claude Sonnet 5 through August 31, 2026. See [Pricing](/docs/en/about-claude/pricing#claude-sonnet-5-introductory-pricing).*
<Info>
Claude Mythos 5 and Claude Mythos Preview are offered separately for defensive cybersecurity workflows as part of [Project Glasswing](https://anthropic.com/glasswing). Access is invitation-only and there is no self-serve sign-up.
@@ -112,41 +112,41 @@ Claude Fable 5 is generally available on the Claude API, Amazon Bedrock, Claude
</Tip>
<Note>
On Claude Opus 4.8, the `effort` parameter defaults to `high` on all surfaces, including the Claude API, Claude Code, and claude.ai. On Claude Sonnet 5, it defaults to `high` on the Claude API and Claude Code. Set `effort` explicitly to use a different level. See [Effort](/docs/en/build-with-claude/effort) for guidance on choosing a level.
On Claude Opus 4.8, the `effort` parameter defaults to `high` on all surfaces, including the Claude API, Claude Code, and claude.ai. On Claude Opus 5 and Claude Sonnet 5, it defaults to `high` on the Claude API and Claude Code. Set `effort` explicitly to use a different level. See [Effort](/docs/en/build-with-claude/effort) for guidance on choosing a level.
</Note>
<Note>
The Max output values in the table apply to the synchronous Messages API. On the [Message Batches API](/docs/en/build-with-claude/batch-processing#extended-output-beta), Claude Opus 4.8, Opus 4.7, Opus 4.6, Sonnet 5, and Sonnet 4.6 support up to 300k output tokens by using the `output-300k-2026-03-24` beta header.
The Max output values in the table apply to the synchronous Messages API. On the [Message Batches API](/docs/en/build-with-claude/batch-processing#extended-output-beta), Claude Opus 5, Opus 4.8, Opus 4.7, Opus 4.6, Sonnet 5, and Sonnet 4.6 support up to 300k output tokens by using the `output-300k-2026-03-24` beta header.
</Note>
<AccordionGroup>
<Accordion title="Legacy models">
The following models are still available. Consider migrating to current models for improved performance:
| Feature | Claude Opus 4.7 | Claude Opus 4.6 | Claude Sonnet 4.6 | Claude Sonnet 4.5 | Claude Opus 4.5 | Claude Opus 4.1 (deprecated) |
| -------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- |
| **Claude API ID** | claude-opus-4-7 | claude-opus-4-6 | claude-sonnet-4-6 | claude-sonnet-4-5-20250929 | claude-opus-4-5-20251101 | claude-opus-4-1-20250805 |
| **Claude API alias** | claude-opus-4-7 | claude-opus-4-6 | claude-sonnet-4-6 | claude-sonnet-4-5 | claude-opus-4-5 | claude-opus-4-1 |
| **AWS Bedrock ID** | anthropic.claude-opus-4-76 | anthropic.claude-opus-4-6-v1 | anthropic.claude-sonnet-4-6 | anthropic.claude-sonnet-4-5-20250929-v1:0 | anthropic.claude-opus-4-5-20251101-v1:0 | anthropic.claude-opus-4-1-20250805-v1:0 |
| **Google Cloud ID** | claude-opus-4-7 | claude-opus-4-6 | claude-sonnet-4-6 | claude-sonnet-4-5\@20250929 | claude-opus-4-5\@20251101 | claude-opus-4-1\@20250805 |
| **Pricing** | $5 / input MTok $25 / output MTok | $5 / input MTok $25 / output MTok | $3 / input MTok $15 / output MTok | $3 / input MTok $15 / output MTok | $5 / input MTok $25 / output MTok | $15 / input MTok $75 / output MTok |
| **[Extended thinking (`thinking.type: "enabled"`)](/docs/en/build-with-claude/extended-thinking)** | No | Yes (deprecated) | Yes (deprecated) | Yes | Yes | Yes |
| **[Adaptive thinking](/docs/en/build-with-claude/thinking-steering-and-cost)** | Yes | Yes | Yes | No | No | No |
| **Comparative latency** | Moderate | Moderate | Fast | Fast | Moderate | Moderate |
| **Context window** | <Tooltip tooltipContent="~555k words \ ~2.5M unicode characters (Opus 4.7 uses a new tokenizer)">1M tokens</Tooltip> | <Tooltip tooltipContent="~750k words \ ~3.4M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~750k words \ ~3.4M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> |
| **Max output** | 128k tokens | 128k tokens | 128k tokens | 64k tokens | 64k tokens | 32k tokens |
| **Reliable knowledge cutoff** | Jan 20265 | May 20255 | Aug 20255 | Jan 20255 | May 20255 | Jan 20255 |
| **Training data cutoff** | Jan 2026 | Aug 2025 | Jan 2026 | Jul 2025 | Aug 2025 | Mar 2025 |
| Feature | Claude Opus 4.8 | Claude Opus 4.7 | Claude Opus 4.6 | Claude Sonnet 4.6 | Claude Sonnet 4.5 | Claude Opus 4.5 | Claude Opus 4.1 (deprecated) |
| -------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- |
| **Claude API ID** | claude-opus-4-8 | claude-opus-4-7 | claude-opus-4-6 | claude-sonnet-4-6 | claude-sonnet-4-5-20250929 | claude-opus-4-5-20251101 | claude-opus-4-1-20250805 |
| **Claude API alias** | claude-opus-4-8 | claude-opus-4-7 | claude-opus-4-6 | claude-sonnet-4-6 | claude-sonnet-4-5 | claude-opus-4-5 | claude-opus-4-1 |
| **AWS Bedrock ID** | anthropic.claude-opus-4-86 | anthropic.claude-opus-4-76 | anthropic.claude-opus-4-6-v1 | anthropic.claude-sonnet-4-6 | anthropic.claude-sonnet-4-5-20250929-v1:0 | anthropic.claude-opus-4-5-20251101-v1:0 | anthropic.claude-opus-4-1-20250805-v1:0 |
| **Google Cloud ID** | claude-opus-4-8 | claude-opus-4-7 | claude-opus-4-6 | claude-sonnet-4-6 | claude-sonnet-4-5\@20250929 | claude-opus-4-5\@20251101 | claude-opus-4-1\@20250805 |
| **Pricing** | $5 / input MTok $25 / output MTok | $5 / input MTok $25 / output MTok | $5 / input MTok $25 / output MTok | $3 / input MTok $15 / output MTok | $3 / input MTok $15 / output MTok | $5 / input MTok $25 / output MTok | $15 / input MTok $75 / output MTok |
| **[Extended thinking (`thinking.type: "enabled"`)](/docs/en/build-with-claude/extended-thinking)** | No | No | Yes (deprecated) | Yes (deprecated) | Yes | Yes | Yes |
| **[Adaptive thinking](/docs/en/build-with-claude/thinking)** | Yes | Yes | Yes | Yes | No | No | No |
| **Comparative latency** | Moderate | Moderate | Moderate | Fast | Fast | Moderate | Moderate |
| **Context window** | <Tooltip tooltipContent="~555k words \ ~2.5M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~555k words \ ~2.5M unicode characters (Opus 4.7 uses a new tokenizer)">1M tokens</Tooltip> | <Tooltip tooltipContent="~750k words \ ~3.4M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~750k words \ ~3.4M unicode characters">1M tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> | <Tooltip tooltipContent="~150k words \ ~680k unicode characters">200k tokens</Tooltip> |
| **Max output** | 128k tokens | 128k tokens | 128k tokens | 128k tokens | 64k tokens | 64k tokens | 32k tokens |
| **Reliable knowledge cutoff** | Jan 20265 | Jan 20265 | May 20255 | Aug 20255 | Jan 20255 | May 20255 | Jan 20255 |
| **Training data cutoff** | Jan 2026 | Jan 2026 | Aug 2025 | Jan 2026 | Jul 2025 | Aug 2025 | Mar 2025 |
<Warning>
Claude Opus 4.1 (`claude-opus-4-1-20250805`) is deprecated and will be retired on August 5, 2026. Migrate to [Claude Opus 4.8](/docs/en/about-claude/models/migration-guide#migrating-from-claude-opus-47) before the retirement date.
Claude Opus 4.1 (`claude-opus-4-1-20250805`) is deprecated and will be retired on August 5, 2026. Migrate to [Claude Opus 5](/docs/en/about-claude/models/migration-guide#migrating-from-claude-opus-4-8-to-claude-opus-5) before the retirement date.
See [model deprecations](/docs/en/about-claude/model-deprecations) for details.
</Warning>
*5 - **Reliable knowledge cutoff** indicates the date through which a model's knowledge is most extensive and reliable. **Training data cutoff** is the broader date range of training data used.*
*5 **Reliable knowledge cutoff** indicates the date through which a model's knowledge is most extensive and reliable. **Training data cutoff** is the broader date range of training data used.*
*6 - Claude Opus 4.7 is available on Bedrock through [Claude in Amazon Bedrock](/docs/en/build-with-claude/claude-in-amazon-bedrock) (the Messages-API Bedrock endpoint).*
*6 Claude Opus 4.8 and Claude Opus 4.7 are available on Bedrock through [Claude in Amazon Bedrock](/docs/en/build-with-claude/claude-in-amazon-bedrock) (the Messages-API Bedrock endpoint).*
</Accordion>
</AccordionGroup>
@@ -154,7 +154,7 @@ Claude Fable 5 is generally available on the Claude API, Amazon Bedrock, Claude
Current Claude models excel in:
* **Performance:** Top-tier results in reasoning, coding, multilingual tasks, long-context handling, honesty, and image processing. See [Prompting Claude Sonnet 5](/docs/en/build-with-claude/prompt-engineering/prompting-claude-sonnet-5) and [Prompting Claude Opus 4.8](/docs/en/build-with-claude/prompt-engineering/prompting-claude-opus-4-8) for model-specific prompting guidance.
* **Performance:** Top-tier results in reasoning, coding, multilingual tasks, long-context handling, honesty, and image processing. See [Prompting best practices](/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices) for general and model-specific prompting guidance.
* **Engaging responses:** Claude models are ideal for applications that require rich, human-like interactions.
@@ -163,11 +163,9 @@ Current Claude models excel in:
* **Output quality:** When migrating from a previous model generation, you may notice larger improvements in overall performance.
## Migrating to Claude Opus 4.8
## Migrating to Claude Opus 5
If you're currently using Claude Opus 4.7 or earlier Claude models, see [Migrating to Claude Opus 4.8](/docs/en/about-claude/models/migration-guide#migrating-from-claude-opus-47).
If you're currently using Claude Opus 4.6 or older Claude models, see [Migrating to Claude Opus 4.8 from Claude Opus 4.6](/docs/en/about-claude/models/migration-guide#migrating-from-claude-opus-46).
If you're currently using Claude Opus 4.8 or earlier Claude models, see [Migrating to Claude Opus 5](/docs/en/about-claude/models/migration-guide#migrating-from-claude-opus-4-8-to-claude-opus-5).
## Get started with Claude
@@ -77,12 +77,12 @@ The advisor must be at least as capable as the main model. Fable 5 satisfies the
| Sonnet 4.6 | Fable, Opus, Sonnet | |
| Sonnet 5 | Fable, Opus, Sonnet 5 | A Sonnet 4.6 advisor is rejected |
| Opus 4.6 | Fable, Opus, Sonnet 5 | Sonnet 5 and Opus 4.6 are ranked as equally capable, so an Opus 4.6 main accepts a Sonnet 5 advisor |
| Opus 4.7 or later | Fable, Opus 4.7, Opus 4.8 | Opus 4.7 and Opus 4.8 are ranked as equally capable, so either accepts the other as an advisor. An Opus 4.7 main with an Opus 4.6 or Sonnet 5 advisor is rejected |
| Opus 4.7 or later | Fable, and Opus 4.7 or later | Opus 4.7 and later Opus models are ranked as equally capable, so any of them accepts another as an advisor. An Opus 4.7 main with an Opus 4.6 or Sonnet 5 advisor is rejected |
| Fable 5 (v2.1.170+) | Fable | An Opus or Sonnet advisor is rejected. Fable isn't offered as the advisor, so a Fable 5 main model runs without one |
Fable 5 requires Claude Code v2.1.170 or later and Fable 5 access, whether it acts as the main model or the advisor.
Set the advisor as `opus` or `sonnet`, or as `fable` once the rollout returns it as an option. These aliases resolve to the latest version of each model. You can also pass a full model ID such as `claude-opus-4-8`.
Set the advisor as `opus` or `sonnet`, or as `fable` once the rollout returns it as an option. These aliases resolve to the latest version of each model. You can also pass a full model ID such as `claude-opus-5`.
Subagents inherit the configured advisor and apply the same pairing check against their own model.
@@ -248,7 +248,7 @@ When enabling Amazon Bedrock for Claude Code, keep the following in mind:
Set these environment variables to specific Amazon Bedrock model IDs.
Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Amazon Bedrock resolves to Opus 4.8, and without `ANTHROPIC_DEFAULT_SONNET_MODEL`, the `sonnet` alias resolves to Sonnet 4.5. This example pins each alias to a specific version:
Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Amazon Bedrock resolves to Opus 5, and without `ANTHROPIC_DEFAULT_SONNET_MODEL`, the `sonnet` alias resolves to Sonnet 4.5. This example pins each alias to a specific version:
```bash
export ANTHROPIC_DEFAULT_OPUS_MODEL='us.anthropic.claude-opus-4-8'
@@ -262,7 +262,7 @@ Claude Code uses these default models when no pinning variables are set:
| Model type | Default value |
| :--------------- | :--------------------------------------------- |
| Primary model | `us.anthropic.claude-opus-4-8` |
| Primary model | `us.anthropic.claude-opus-5` |
| Small/fast model | `us.anthropic.claude-sonnet-4-5-20250929-v1:0` |
Background tasks such as session title generation use the small/fast model, normally a Haiku-class model. On Amazon Bedrock, Claude Code uses the default Sonnet model for background tasks because Haiku may not be enabled in every account or region. Two selections change which model carries them:
@@ -274,7 +274,7 @@ Background tasks such as session title generation use the small/fast model, norm
Opus models have a higher per-token price than Sonnet models, so a deployment that doesn't pin a primary model is billed at the Opus rate once it updates to v2.1.207 or later. To keep Sonnet 4.5 as the primary model, set `ANTHROPIC_MODEL` to its full model ID. A deployment that steers the default with `ANTHROPIC_DEFAULT_SONNET_MODEL` and doesn't set `ANTHROPIC_DEFAULT_OPUS_MODEL` keeps its steered Sonnet model as the default.
</Warning>
{/* min-version: 2.1.207 */}Before v2.1.207, the primary model on Amazon Bedrock defaulted to Sonnet 4.5, the `opus` alias resolved to Opus 4.6, and background tasks always used the primary model.
{/* min-version: 2.1.219 */}On v2.1.207 through v2.1.218, the primary model on Amazon Bedrock defaulted to Opus 4.8 and the `opus` alias resolved to Opus 4.8. {/* min-version: 2.1.207 */}Before v2.1.207, the primary model defaulted to Sonnet 4.5, the `opus` alias resolved to Opus 4.6, and background tasks always used the primary model.
To customize models further, use one of these methods:
@@ -145,7 +145,7 @@ Claude Platform on AWS is opt-in even when AWS credentials are present in your e
Claude Platform on AWS uses the same model IDs as the direct Claude API.
The default aliases `fable`, `opus`, `sonnet`, and `haiku` resolve to Claude Code's built-in defaults for Claude Platform on AWS, which can lag the newest release. Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias resolves to Opus 4.8. {/* min-version: 2.1.207 */}Before v2.1.207, it resolved to Opus 4.7.
The default aliases `fable`, `opus`, `sonnet`, and `haiku` resolve to Claude Code's built-in defaults for Claude Platform on AWS, which can lag the newest release. Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias resolves to Opus 5. {/* min-version: 2.1.219 */}Before v2.1.219, it resolved to Opus 4.8, {/* min-version: 2.1.207 */}and before v2.1.207 to Opus 4.7.
If you deploy Claude Code to a team, pin the model IDs explicitly so a new release doesn't move everyone at once:
@@ -114,7 +114,7 @@ Customize Claude Code's behavior with these command-line flags. `claude --help`
| `--remote-control-session-name-prefix <prefix>` | Prefix for auto-generated [Remote Control](/docs/en/remote-control) session names when no explicit name is set. Defaults to your machine's hostname, producing names like `myhost-graceful-unicorn`. Set `CLAUDE_REMOTE_CONTROL_SESSION_NAME_PREFIX` for the same effect | `claude remote-control --remote-control-session-name-prefix dev-box` |
| `--replay-user-messages` | Re-emit user messages from stdin back on stdout for acknowledgment. Requires `--input-format stream-json` and `--output-format stream-json` | `claude -p --input-format stream-json --output-format stream-json --verbose --replay-user-messages` |
| `--resume`, `-r` | Resume a specific session by ID or name, or show an interactive picker to choose a session. The picker and name search include sessions that added this directory with `/add-dir`; passing a session ID searches only the current project directory and its git worktrees. As of v2.1.144, [background sessions](/docs/en/agent-view) appear in the picker marked with `bg` | `claude --resume auth-refactor` |
| `--safe-mode` | Start with all customizations disabled to troubleshoot a broken configuration: CLAUDE.md, skills, plugins, hooks, MCP servers, custom commands and agents, output styles, workflows, custom themes, custom keybindings, status line and file-suggestion commands, LSP servers, and auto-memory do not load. Authentication, model selection, built-in tools, and permissions work normally, which differs from [`--bare`](/docs/en/headless#start-faster-with-bare-mode). Managed settings policy still applies, including policy-configured hooks, status line, and file-suggestion commands; managed plugins, managed skills, managed CLAUDE.md, and policy-configured MCP servers do not. Useful for checking whether a customization is what triggers [automatic fallback from Fable 5](/docs/en/model-config#automatic-model-fallback). Sets [`CLAUDE_CODE_SAFE_MODE`](/docs/en/env-vars) | `claude --safe-mode` |
| `--safe-mode` | Start with all customizations disabled to troubleshoot a broken configuration: CLAUDE.md, skills, plugins, hooks, MCP servers, custom commands and agents, output styles, workflows, custom themes, custom keybindings, status line and file-suggestion commands, LSP servers, and auto-memory do not load. Authentication, model selection, built-in tools, and permissions work normally, which differs from [`--bare`](/docs/en/headless#start-faster-with-bare-mode). Managed settings policy still applies, including policy-configured hooks, status line, and file-suggestion commands; managed plugins, managed skills, managed CLAUDE.md, and policy-configured MCP servers do not. Useful for checking whether a customization is what triggers [automatic model fallback](/docs/en/model-config#automatic-model-fallback). Sets [`CLAUDE_CODE_SAFE_MODE`](/docs/en/env-vars) | `claude --safe-mode` |
| `--session-id` | Use a specific session ID for the conversation (must be a valid UUID) | `claude --session-id "550e8400-e29b-41d4-a716-446655440000"` |
| `--setting-sources` | Comma-separated list of setting sources to load (`user`, `project`, `local`) | `claude --setting-sources user,project` |
| `--settings` | Path to a settings JSON file or an inline JSON string. Values you set here override the same keys in your `settings.json` files for this session. Keys you omit keep their file-based values. The file must be a regular file no larger than 2 MiB. See [settings precedence](/docs/en/settings#settings-precedence) | `claude --settings ./settings.json` |
@@ -75,7 +75,7 @@ Not every command appears for every user. Availability depends on your platform,
| `/desktop` | Continue the current session in the Claude Code Desktop app. Requires macOS or Windows and a Claude subscription. Alias: `/app` |
| `/diff` | Open an interactive diff viewer showing uncommitted changes and per-turn diffs. Use left/right arrows to switch between the current git diff and individual Claude turns, and up/down to browse files. Press Enter to open the selected file's diff, scroll it with up/down or PageUp/PageDown, and press Esc to return to the file list. As of v2.1.198, the open viewer also refreshes automatically when the repository's git state changes outside the session, such as a branch switch or commit in another terminal |
| `/doctor` | **[Skill](/docs/en/skills#bundled-skills).** Run a setup checkup that diagnoses issues and can fix them. Checks installation health, including duplicate or leftover installs, `PATH` problems, and unparseable settings files. Finds unused skills, MCP servers, and plugins versus their context cost, flags slow [hooks](/docs/en/hooks), and checks for a newer version on your release channel. Deduplicates local `CLAUDE.md` files against checked-in ones, trims checked-in [`CLAUDE.md`](/docs/en/memory) files by cutting content Claude could derive from the codebase, and migrates the always-loaded guidance that remains into [skills](/docs/en/skills) and nested `CLAUDE.md` files that load on demand. The trim cuts sections such as directory layouts, dependency lists, and architecture overviews, and keeps pitfalls, rationale, and conventions that differ from tool defaults. Also offers to make [auto mode](/docs/en/permissions#permission-modes) your default and to [pre-approve](/docs/en/permissions) frequently denied read-only commands. Reports findings first and asks for confirmation before changing anything. From the terminal, `claude doctor` prints read-only installation diagnostics without starting a session. Alias: `/checkup`. The `CLAUDE.md` trim check requires Claude Code v2.1.206 or later. Before v2.1.206, the version check compared Homebrew installs against the `autoUpdatesChannel` setting rather than the [installed cask's channel](/docs/en/setup#configure-release-channel). Before v2.1.205, `/doctor` opened a read-only diagnostics screen and pressing `f` sent the report to Claude |
| `/effort [level\|auto]` | Set the model [effort level](/docs/en/model-config#adjust-effort-level). Accepts `low`, `medium`, `high`, `xhigh`, `max`, or `ultracode`; available levels depend on the model, and `max` and `ultracode` are session-only. `ultracode` is a Claude Code setting that combines `xhigh` reasoning with automatic [workflow](/docs/en/workflows#let-claude-decide-with-ultracode) orchestration. `auto` resets to the model default. Without an argument, opens an interactive slider; use left and right arrows to pick a level and `Enter` to apply. Takes effect immediately without waiting for the current response to finish. Also available in non-interactive mode (`-p`) with a level argument, where it applies to the current session only and isn't saved as your default; requires Claude Code v2.1.205 or later. On Fable 5, Opus 4.8, and Opus 4.7, a non-interactive `/effort` reports `Not applied` while the [model-default effort hold](/docs/en/model-config#adjust-effort-level) is in force, so pass `--effort` at launch instead |
| `/effort [level\|auto]` | Set the model [effort level](/docs/en/model-config#adjust-effort-level). Accepts `low`, `medium`, `high`, `xhigh`, `max`, or [`ultracode`](/docs/en/workflows#let-claude-decide-with-ultracode); available levels depend on the model, and `max` and `ultracode` are session-only. `auto` resets to the model default. Without an argument, opens an interactive slider. Takes effect immediately without waiting for the current response to finish. Also available in non-interactive mode (`-p`) with a level argument, where it applies to the current session only; requires Claude Code v2.1.205 or later. While the [model-default effort hold](/docs/en/model-config#adjust-effort-level) is in force, a non-interactive `/effort` reports `Not applied`, so pass `--effort` at launch instead |
| `/exit` | Exit the CLI. In an attached [background session](/docs/en/agent-view#attach-to-a-session), this detaches and the session keeps running. Alias: `/quit` |
| `/export [filename]` | Export the current conversation as plain text. With a filename, writes directly to that file. Without, opens a dialog to copy to clipboard or save to a file |
| `/fast [on\|off]` | Toggle [fast mode](/docs/en/fast-mode) on or off. In non-interactive mode (`-p`), `/fast` works only in a session launched with fast mode in its [`--settings`](/docs/en/cli-reference#cli-flags) value, for example `claude -p --settings '{"fastMode": true}'`; the toggle then applies to the current session only and isn't saved as your default, and in any other non-interactive session the command reports that fast mode isn't available. Requires Claude Code v2.1.205 or later |
@@ -203,7 +203,9 @@ debugging, or anything high-stakes. Drop to *Haiku* for quick questions,
formatting, and mechanical edits where speed wins. *Fable 5* is the most
capable model for your hardest, longest-running tasks; it is not the
default, so select it with `/model fable`, and note that cybersecurity and
biology content falls back to Opus automatically.
biology content falls back to Opus automatically. Opus 5 runs its own
checks, so flagged cybersecurity content switches models and flagged
biology content is refused.
*Try it now:* type `/model` and pick Sonnet if you haven't already. It is
the right default for most tasks.
@@ -214,7 +216,7 @@ the right default for most tasks.
| Model | Best for |
| - | - |
| Fable 5 | The hardest, longest-running tasks. Opt-in only: select it with `/model fable`. Cybersecurity or biology content [falls back to Opus](/docs/en/model-config#automatic-model-fallback) |
| Opus | Large-scale refactors, complex debugging, architecture decisions, high-stakes changes |
| Opus | Large-scale refactors, complex debugging, architecture decisions, high-stakes changes. On Opus 5, cybersecurity or biology content triggers [automatic model fallback or a refusal](/docs/en/model-config#automatic-model-fallback) |
| Sonnet | Everyday feature work, bug fixes, tests, documentation, code review. Recommended default. |
| Haiku | Quick questions, formatting, mechanical edits, rapid iteration |
@@ -80,7 +80,7 @@ The `dontAsk` permission mode is available only in the [CLI](/docs/en/permission
Auto mode is available to all users on the Anthropic API and requires Claude Opus 4.6 or later, Sonnet 4.6 or later, or Fable 5. Organization administrators can turn auto mode off with the `disableAutoMode` key in [managed settings](#managed-settings).
In Enterprise deployments that route Desktop to Google Cloud's Agent Platform, auto mode is [available by default](/docs/en/permission-modes#enable-auto-mode-on-bedrock-agent-platform-or-foundry), and only Claude Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5 are supported there. Before Claude Code v2.1.207, Enterprise deployments on Google Cloud's Agent Platform had to set `CLAUDE_CODE_ENABLE_AUTO_MODE` to enable auto mode.
In Enterprise deployments that route Desktop to Google Cloud's Agent Platform, auto mode is [available by default](/docs/en/permission-modes#enable-auto-mode-on-bedrock-agent-platform-or-foundry), and only Claude Sonnet 5, Opus 4.7 or later, and Fable 5 are supported there. Before Claude Code v2.1.207, Enterprise deployments on Google Cloud's Agent Platform had to set `CLAUDE_CODE_ENABLE_AUTO_MODE` to enable auto mode.
Start complex tasks in Plan so Claude maps out an approach before making changes. Once you approve the plan, switch to Accept edits or Manual to execute it. See [explore first, then plan, then code](/docs/en/best-practices#explore-first-then-plan-then-code) for more on this workflow.
@@ -404,6 +404,7 @@ Numeric variables such as timeouts, token budgets, and retry counts accept scien
| `VERTEX_REGION_CLAUDE_4_6_SONNET` | Override region for Claude Sonnet 4.6 when using Google Cloud's Agent Platform |
| `VERTEX_REGION_CLAUDE_4_7_OPUS` | Override region for Claude Opus 4.7 when using Google Cloud's Agent Platform. Added in v2.1.111 |
| `VERTEX_REGION_CLAUDE_4_8_OPUS` | Override region for Claude Opus 4.8 when using Google Cloud's Agent Platform. Added in v2.1.154 |
| `VERTEX_REGION_CLAUDE_5_OPUS` | Override region for Claude Opus 5 when using Google Cloud's Agent Platform. Added in v2.1.219 |
| `VERTEX_REGION_CLAUDE_5_SONNET` | Override region for Claude Sonnet 5 when using Google Cloud's Agent Platform. Added in v2.1.197 |
| `VERTEX_REGION_CLAUDE_FABLE_5` | Override region for Claude Fable 5 when using Google Cloud's Agent Platform. Added in v2.1.170 |
| `VERTEX_REGION_CLAUDE_HAIKU_4_5` | Override region for Claude Haiku 4.5 when using Google Cloud's Agent Platform |
@@ -959,6 +959,7 @@ There's an issue with the selected model (claude-...). It may not exist or you m
- **Agent SDK**: the error text omits the hint because the model is set programmatically. Set [`model` on `Options`](/docs/en/agent-sdk/typescript#options) in TypeScript or [`ClaudeAgentOptions(model=...)`](/docs/en/agent-sdk/python#claudeagentoptions) in Python, and handle the structured `model_not_found` error to surface your own retry or model picker.
- Use an alias such as `sonnet` or `opus` instead of a full versioned ID. Aliases resolve to a maintained default so they don't go stale. See [Model configuration](/docs/en/model-config).
- If the wrong model keeps coming back in the CLI, a stale ID is set somewhere. Check in [priority order](/docs/en/model-config#setting-your-model): the `--model` flag, the `ANTHROPIC_MODEL` environment variable, then the `model` field in `.claude/settings.local.json`, your project's `.claude/settings.json`, and `~/.claude/settings.json`. Remove the stale value and Claude Code falls back to your account default.
- A newly launched model can be available on the Anthropic API before Amazon Bedrock, Google Cloud's Agent Platform, or Microsoft Foundry offers it. If you pinned a new model ID on one of those providers and see this error, check your provider's model catalog for availability in your region, and keep the previous version pinned until the new one appears there.
- Claude Code reports an expired claude.ai login as [Login expired](#login-expired), not as this error. Before v2.1.206, an expired login that could no longer be refreshed failed every model with this error; run `/login` if you see that on an older version.
- For Google Cloud's Agent Platform deployments, see [Google Cloud's Agent Platform troubleshooting](/docs/en/google-vertex-ai#troubleshooting).
@@ -1013,7 +1014,7 @@ Claude Code treats a model family alias, one of `opus`, `sonnet`, `haiku`, or `f
### thinking.type.enabled is not supported for this model
Your Claude Code version is older than the minimum for Sonnet 5, Opus 4.8, or Opus 4.7. The CLI sent a thinking configuration the model no longer accepts.
Your Claude Code version is older than the minimum for the selected model. The CLI sent a thinking configuration the model no longer accepts.
```text
API Error: 400 ... "thinking.type.enabled" is not supported for this model. Use "thinking.type.adaptive" and "output_config.effort" to control thinking behavior.
@@ -1021,9 +1022,9 @@ API Error: 400 ... "thinking.type.enabled" is not supported for this model. Use
**What to do:**
- Run `claude update` and restart Claude Code. Opus 4.7 needs v2.1.111 or later. Opus 4.8 needs v2.1.154 or later. Sonnet 5 needs v2.1.197 or later
- Run `claude update` and restart Claude Code. Opus 4.7 needs v2.1.111 or later. Opus 4.8 needs v2.1.154 or later. Sonnet 5 needs v2.1.197 or later. Opus 5 needs v2.1.219 or later
- If you can't upgrade, run `/model` and select Opus 4.6 or Sonnet 4.6 instead
- If you hit this in the [Agent SDK](/docs/en/agent-sdk/overview), upgrade the SDK package instead. Opus 4.8 needs TypeScript SDK v0.3.154 or later and Python SDK v0.2.88 or later. Sonnet 5 needs TypeScript SDK v0.3.197 or later
- If you hit this in the [Agent SDK](/docs/en/agent-sdk/overview), upgrade the SDK package instead. Opus 4.8 needs TypeScript SDK v0.3.154 or later and Python SDK v0.2.88 or later. Sonnet 5 needs TypeScript SDK v0.3.197 or later. Opus 5 needs TypeScript SDK v0.3.219 or later
### Thinking budget exceeds output limit
@@ -1561,7 +1562,7 @@ If Claude's answers seem less capable than you expect but no error is shown, the
- A configured [`--fallback-model`](/docs/en/cli-reference#cli-flags) takes over after an availability error, for that turn only, with a notice in the transcript
- An Amazon Bedrock or Google Cloud's Agent Platform startup check finds your default model unavailable
- [Automatic model fallback](/docs/en/model-config#automatic-model-fallback) on Fable 5 moves the session to the default Opus model and shows a notice in the transcript
- [Automatic model fallback](/docs/en/model-config#automatic-model-fallback) on Fable 5 and Opus 5 moves the session to the flagged category's fallback model, when that category has one, and shows a notice in the transcript
The Model selection check below catches the second and third cases; the first appears as a transcript notice rather than a `/model` change. [Model configuration](/docs/en/model-config) explains when each fallback applies.
@@ -11,14 +11,14 @@ Fast mode is in [research preview](#research-preview). The feature, pricing, and
Fast mode is a high-speed configuration for Claude Opus, making the model up to 2.5x faster at a higher cost per token. Toggle it on with `/fast` when you need speed for interactive work like rapid iteration or live debugging, and toggle it off when cost matters more than latency.
Fast mode is not a different model. It uses Claude Opus with a different API configuration that prioritizes speed over cost efficiency. You get identical quality and capabilities with faster responses. Fast mode is supported on Opus 4.8 and Opus 4.7. It is not available on Sonnet, Haiku, or other models.
Fast mode is not a different model. It uses Claude Opus with a different API configuration that prioritizes speed over cost efficiency. You get identical quality and capabilities with faster responses. Fast mode is supported on Opus 5, Opus 4.8, and Opus 4.7. It is not available on Sonnet, Haiku, or other models.
Fast mode for Opus 4.7 is deprecated as of June 25, 2026, and will be removed on July 24, 2026. After removal, fast mode requests on Opus 4.7 return an error and do not fall back to standard Opus 4.7. Migrate to Opus 4.8 to keep the speedup.
Fast mode for Opus 4.7 is deprecated as of June 25, 2026, and will be removed on July 24, 2026. After removal, fast mode requests on Opus 4.7 return an error and do not fall back to standard Opus 4.7. Migrate to Opus 5 or Opus 4.8 to keep the speedup.
What to know:
- Use `/fast` to toggle on fast mode in the Claude Code CLI. Fast mode is not supported in the VS Code extension.
- Fast mode pricing per MTok input/output is $10/$50 on Opus 4.8 and $30/$150 on Opus 4.7.
- Fast mode pricing per MTok input/output is $10/$50 on Opus 5 and Opus 4.8, and $30/$150 on Opus 4.7.
- Available to all Claude Code users on subscription plans (Pro/Max/Team/Enterprise) and Claude Console.
- For Claude Code users on subscription plans (Pro/Max/Team/Enterprise), fast mode is available via usage credits only and not included in the subscription rate limits.
@@ -46,7 +46,7 @@ Switching to a model that doesn't support fast mode turns fast mode off. Switchi
Whenever a model switch turns fast mode on or off, Claude Code shows a `Fast mode ON` or `Fast mode OFF` confirmation, and the `↯` icon appears while fast mode is on. This holds whether you switch with `/model`, with [`/config model=<model>`](/docs/en/settings), or from a device connected through [Remote Control](/docs/en/remote-control); before v2.1.218, switches through `/config` or Remote Control changed fast mode without the confirmation.
Opus 4.8 is the fast mode default in Claude Code v2.1.154 and later. On v2.1.142 through v2.1.153, fast mode defaults to Opus 4.7.
Opus 5 is the fast mode default in Claude Code v2.1.219 and later. Before v2.1.219, fast mode defaulted to Opus 4.8 on v2.1.154 through v2.1.218, and to Opus 4.7 on v2.1.142 through v2.1.153.
## Understand the cost tradeoff
@@ -54,6 +54,7 @@ Fast mode has higher per-token pricing than standard Opus, with the multiplier v
| Model | Input (MTok) | Output (MTok) |
| - | - | - |
| Opus 5 | $10 | $50 |
| Opus 4.8 | $10 | $50 |
| Opus 4.7 | $30 | $150 |
@@ -146,7 +147,7 @@ This is useful for controlling costs in organizations where users run multiple c
## Handle rate limits
Fast mode has separate rate limits from standard Opus. Fast mode on Opus 4.8 and Opus 4.7 shares the same rate limit pool: usage on either of them draws from the same limits. When you hit the fast mode rate limit or run out of usage credits:
Fast mode has separate rate limits from standard Opus. All supported Opus models share one fast mode rate limit pool: usage on any of them draws from the same limits. When you hit the fast mode rate limit or run out of usage credits:
1. Fast mode automatically falls back to standard speed
2. The `↯` icon turns gray to indicate cooldown
@@ -161,7 +161,7 @@ See note 4
See note 4
1 On Google Cloud's Agent Platform, web search is available for Claude 4 models and later.
2 On these providers, auto mode supports only Claude Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5. See [Auto mode configuration](/docs/en/auto-mode-config). In v2.1.158 through v2.1.206, auto mode on these providers also required setting `CLAUDE_CODE_ENABLE_AUTO_MODE=1`; v2.1.207 removed the requirement.
2 On these providers, auto mode supports only Claude Sonnet 5, Opus 4.7 or later, and Fable 5. See [Auto mode configuration](/docs/en/auto-mode-config). In v2.1.158 through v2.1.206, auto mode on these providers also required setting `CLAUDE_CODE_ENABLE_AUTO_MODE=1`; v2.1.207 removed the requirement.
3 Explicit intervals such as `/loop every 2 hours` work on every provider. On Amazon Bedrock, Claude Platform on AWS, Google Cloud's Agent Platform, and Microsoft Foundry, `/loop` cannot pick its own interval or supply the default maintenance prompt, so a prompt with no interval runs every 10 minutes, and `/loop` with no arguments shows the usage message. See [Scheduled tasks](/docs/en/scheduled-tasks).
4 Subject to your agreement with the cloud provider.
5 Dashboard and API only. [Contribution metrics](/docs/en/analytics#enable-contribution-metrics) requires a claude.ai Team or Enterprise organization.
@@ -177,7 +177,7 @@ Each tab lists what is unavailable or partially supported on that provider, with
**Partial support:**
- [Desktop](/docs/en/desktop): only via [Claude Desktop on 3P](https://claude.com/docs/third-party/claude-desktop/overview)
- [Auto mode](/docs/en/auto-mode-config): Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5 only
- [Auto mode](/docs/en/auto-mode-config): Sonnet 5, Opus 4.7 or later, and Fable 5 only
- [`/loop`](/docs/en/scheduled-tasks): explicit intervals only
- [Zero Data Retention](/docs/en/zero-data-retention): subject to your AWS agreement
@@ -199,7 +199,7 @@ Each tab lists what is unavailable or partially supported on that provider, with
- [Desktop](/docs/en/desktop): via [managed settings](https://claude.com/docs/third-party/claude-desktop/configuration) or [Claude Desktop on 3P](https://claude.com/docs/third-party/claude-desktop/overview)
- [Web search](/docs/en/tools-reference#websearch-tool-behavior): Claude 4 models and later
- [Auto mode](/docs/en/auto-mode-config): Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5 only
- [Auto mode](/docs/en/auto-mode-config): Sonnet 5, Opus 4.7 or later, and Fable 5 only
- [`/loop`](/docs/en/scheduled-tasks): explicit intervals only
- [Zero Data Retention](/docs/en/zero-data-retention): subject to your Google Cloud agreement
@@ -210,7 +210,7 @@ Each tab lists what is unavailable or partially supported on that provider, with
**Partial support:**
- [Desktop](/docs/en/desktop): only via [Claude Desktop on 3P](https://claude.com/docs/third-party/claude-desktop/overview)
- [Auto mode](/docs/en/auto-mode-config): Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5 only
- [Auto mode](/docs/en/auto-mode-config): Sonnet 5, Opus 4.7 or later, and Fable 5 only
- [`/loop`](/docs/en/scheduled-tasks): explicit intervals only
- [Zero Data Retention](/docs/en/zero-data-retention): subject to your Azure agreement
@@ -193,7 +193,7 @@ Claude Code disables [MCP tool search](/docs/en/mcp#scale-with-mcp-tool-search)
Set these environment variables to specific Google Cloud's Agent Platform model IDs.
Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Google Cloud's Agent Platform resolves to Opus 4.8, and without `ANTHROPIC_DEFAULT_SONNET_MODEL`, the `sonnet` alias resolves to Sonnet 4.5. This example pins each alias to a specific version:
Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Google Cloud's Agent Platform resolves to Opus 5, and without `ANTHROPIC_DEFAULT_SONNET_MODEL`, the `sonnet` alias resolves to Sonnet 4.5. This example pins each alias to a specific version:
```bash
export ANTHROPIC_DEFAULT_OPUS_MODEL='claude-opus-4-8'
@@ -207,7 +207,7 @@ Claude Code uses these default models when no pinning variables are set:
| Model type | Default value |
| :--------------- | :--------------------------- |
| Primary model | `claude-opus-4-8` |
| Primary model | `claude-opus-5` |
| Small/fast model | `claude-sonnet-4-5@20250929` |
Background tasks such as session title generation use the small/fast model, normally a Haiku-class model. On Google Cloud's Agent Platform, Claude Code uses the default Sonnet model for background tasks because Haiku may not be enabled in every project or region. Two selections change which model carries them:
@@ -219,7 +219,7 @@ Background tasks such as session title generation use the small/fast model, norm
Opus models have a higher per-token price than Sonnet models, so a deployment that doesn't pin a primary model is billed at the Opus rate once it updates to v2.1.207 or later. To keep Sonnet 4.5 as the primary model, set `ANTHROPIC_MODEL` to its full model ID. A deployment that steers the default with `ANTHROPIC_DEFAULT_SONNET_MODEL` and doesn't set `ANTHROPIC_DEFAULT_OPUS_MODEL` keeps its steered Sonnet model as the default.
</Warning>
{/* min-version: 2.1.207 */}Before v2.1.207, the primary model on Google Cloud's Agent Platform defaulted to Sonnet 4.5, the `opus` alias resolved to Opus 4.6, and background tasks always used the primary model.
{/* min-version: 2.1.219 */}On v2.1.207 through v2.1.218, the primary model on Google Cloud's Agent Platform defaulted to Opus 4.8 and the `opus` alias resolved to Opus 4.8. {/* min-version: 2.1.207 */}Before v2.1.207, the primary model defaulted to Sonnet 4.5, the `opus` alias resolved to Opus 4.6, and background tasks always used the primary model.
To customize models further:
@@ -155,7 +155,7 @@ export ANTHROPIC_FOUNDRY_RESOURCE={resource}
Set the model variables to match the deployment names you created in step 1.
Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Microsoft Foundry resolves to Opus 4.6. Set it to the Opus 4.8 ID to use the latest model:
Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Microsoft Foundry resolves to Opus 4.6. Set it to the ID of a newer Opus model, such as Opus 4.8:
```bash
export ANTHROPIC_DEFAULT_OPUS_MODEL='claude-opus-4-8'
@@ -43,18 +43,18 @@ The version that the `opus` and `sonnet` aliases resolve to depends on the provi
| Provider | `opus` | `sonnet` |
| :- | :- | :- |
| Anthropic API | Opus 4.8 | Sonnet 5 |
| [Claude Platform on AWS](/docs/en/claude-platform-on-aws) | Opus 4.8 | Sonnet 4.6 |
| Amazon Bedrock, Google Cloud's Agent Platform | Opus 4.8 | Sonnet 4.5 |
| Anthropic API | Opus 5 | Sonnet 5 |
| [Claude Platform on AWS](/docs/en/claude-platform-on-aws) | Opus 5 | Sonnet 4.6 |
| Amazon Bedrock, Google Cloud's Agent Platform | Opus 5 | Sonnet 4.5 |
| Microsoft Foundry | Opus 4.6 | Sonnet 4.5 |
Where an alias resolves to an older model, newer models are available by selecting the full model name explicitly or setting `ANTHROPIC_DEFAULT_OPUS_MODEL` or `ANTHROPIC_DEFAULT_SONNET_MODEL`.
Before v2.1.207, `opus` resolved to Opus 4.7 on Claude Platform on AWS and to Opus 4.6 on Amazon Bedrock and Google Cloud's Agent Platform.
Before v2.1.219, `opus` resolved to Opus 4.8 on the Anthropic API from v2.1.154, and on Claude Platform on AWS, Amazon Bedrock, and Google Cloud's Agent Platform from v2.1.207. Before v2.1.207, `opus` resolved to Opus 4.7 on Claude Platform on AWS and to Opus 4.6 on Amazon Bedrock and Google Cloud's Agent Platform.
Aliases point to the recommended version for your provider and update over time. To pin to a specific version, use the full model name, for example `claude-opus-4-8`, or set the corresponding environment variable like `ANTHROPIC_DEFAULT_OPUS_MODEL`.
Aliases point to the recommended version for your provider and update over time. To pin to a specific version, use the full model name, for example `claude-opus-5`, or set the corresponding environment variable like `ANTHROPIC_DEFAULT_OPUS_MODEL`.
Sonnet 5 requires Claude Code v2.1.197 or later. Opus 4.8 requires v2.1.154 or later. Run `claude update` to upgrade.
Opus 5 requires Claude Code v2.1.219 or later. Sonnet 5 requires v2.1.197 or later. Opus 4.8 requires v2.1.154 or later. Run `claude update` to upgrade.
### Work with Fable 5
@@ -317,14 +317,14 @@ Effort limits are delivered together with [organization model restrictions](#org
The behavior of `default` depends on your account type:
- **Max, Team Premium, Enterprise pay-as-you-go, and Anthropic API**: defaults to Opus 4.8
- **Claude Platform on AWS, Amazon Bedrock, and Google Cloud's Agent Platform**: defaults to Opus 4.8
- **Max, Team Premium, Enterprise pay-as-you-go, and Anthropic API**: defaults to Opus 5
- **Claude Platform on AWS, Amazon Bedrock, and Google Cloud's Agent Platform**: defaults to Opus 5
- **Pro, Team Standard, and Enterprise subscription seats**: defaults to Sonnet 5
- **Microsoft Foundry**: defaults to Sonnet 4.5
Enterprise pay-as-you-go means an Enterprise organization billed by usage rather than by subscription seat.
Before v2.1.207, `default` resolved to Opus 4.7 on Claude Platform on AWS and to Sonnet 4.5 on Amazon Bedrock and Google Cloud's Agent Platform.
Before v2.1.219, `default` resolved to Opus 4.8 on the Anthropic API, Max, Team Premium, and Enterprise pay-as-you-go from v2.1.154, and on Claude Platform on AWS, Amazon Bedrock, and Google Cloud's Agent Platform from v2.1.207. Before v2.1.207, `default` resolved to Opus 4.7 on Claude Platform on AWS and to Sonnet 4.5 on Amazon Bedrock and Google Cloud's Agent Platform.
When an admin has set an [organization default model](#organization-default-model), `default` resolves to that model instead of the account-type default above. Requires Claude Code v2.1.196 or later.
@@ -380,13 +380,20 @@ When a request fails over, Claude Code tries each entry in order until one accep
### Automatic model fallback
This section covers content-based fallback from Fable 5. For availability-based fallback when a model is overloaded or unavailable, see [Fallback model chains](#fallback-model-chains).
This section covers content-based fallback from Fable 5 and Opus 5. For availability-based fallback when a model is overloaded or unavailable, see [Fallback model chains](#fallback-model-chains).
Fable 5 runs with safety classifiers for cybersecurity and biology content. When a classifier flags a request, Claude Code re-runs that request on your provider's default Opus model and shows a notice in the transcript. On the Anthropic API, [LLM gateway](/docs/en/llm-gateway) deployments, and [Claude Platform on AWS](/docs/en/claude-platform-on-aws), that model is Opus 4.8. On the [Claude apps gateway](/docs/en/claude-apps-gateway), it's Opus 4.7 unless you point the [`opus` alias](#environment-variables) at another model.
Fable 5 and Opus 5 run with safety classifiers for cybersecurity and biology content. When a classifier flags a request and the flagged category has a fallback model, Claude Code re-runs the request on that model and shows a notice in the transcript. The fallback model depends on which model refused and which category was flagged:
The session then continues on that Opus model. To return to Fable 5, run `/model fable`.
- **Fable 5**: biology-flagged requests re-run on Opus 5, and cybersecurity-flagged requests re-run on Opus 4.8.
- **Opus 5**: cybersecurity-flagged requests re-run on Opus 4.8. Biology-flagged requests end with a refusal instead, because Opus 5 runs its own biology classifiers with no fallback model.
The fallback target is checked against [`availableModels`](#restrict-model-selection). When it is blocked, no fallback occurs. The refusal is shown as a normal error and the session's model is unchanged.
On Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry, Claude Code resolves these targets through your deployment instead, and if you set `ANTHROPIC_DEFAULT_OPUS_MODEL`, categories that have a fallback re-run on the pinned model; see [Enable fallback on Bedrock, Agent Platform, and Foundry](#enable-fallback-on-bedrock-agent-platform-and-foundry).
After a fallback, the session continues on the fallback model. To return to your original model, run [`/model`](#setting-your-model).
Category-based fallback requires Claude Code v2.1.219 or later. Before v2.1.219, every flagged Fable 5 request re-ran on your provider's default Opus model, and Opus 5 was not a fallback source.
The fallback model is checked against [`availableModels`](#restrict-model-selection). When it is blocked, no fallback occurs. The refusal is shown as a normal error and the session's model is unchanged.
#### Check what triggered fallback
@@ -396,10 +403,11 @@ To check whether customizations are the trigger, start a session with `claude --
#### Ask before switching
To decide what happens each time a request is flagged, rather than switching automatically, run `/config` and turn off "switch models when a message is flagged". A flagged request then pauses the session with two options: switch to the Opus model, or edit the prompt and retry on Fable 5.
To decide what happens each time a request is flagged, rather than switching automatically, run `/config` and turn off "switch models when a message is flagged". A flagged request then pauses the session with two options: switch to the fallback model, or edit the prompt and retry on the current model.
Some cases behave differently:
- When the flagged category has no fallback model, such as a biology flag on Opus 5, the prompt is not shown and the request ends with the refusal.
- If both models flag the same request, you can edit the prompt and retry, or start a new session.
- On mobile [Claude Code on the web](/docs/en/claude-code-on-the-web) sessions, editing and retrying is not supported. Switch models, or continue the session from a desktop browser or the desktop app.
- In [non-interactive mode](/docs/en/cli-reference#cli-flags) and SDK integrations that can't show the prompt, a flagged request ends the turn with a refusal instead.
@@ -409,14 +417,14 @@ Some cases behave differently:
On [Amazon Bedrock](/docs/en/amazon-bedrock), [Google Cloud's Agent Platform](/docs/en/google-vertex-ai), and [Microsoft Foundry](/docs/en/microsoft-foundry), model IDs are provider-specific, so automatic fallback only operates when Claude Code can identify both models involved:
- Claude Code must recognize the current model as Fable 5: the model ID contains `claude-fable-5`, matches the value of `ANTHROPIC_DEFAULT_FABLE_MODEL`, or is mapped with [`modelOverrides`](#override-model-ids-per-version).
- The fallback target must resolve to an Opus model: the value of `ANTHROPIC_DEFAULT_OPUS_MODEL` if set, otherwise an Opus 4.8 entry in the provider's model list.
- Claude Code must recognize the current model as a fallback source. Fable 5 is recognized when the model ID contains `claude-fable-5`, matches the value of `ANTHROPIC_DEFAULT_FABLE_MODEL`, or is mapped with [`modelOverrides`](#override-model-ids-per-version). Opus 5 is recognized by its provider model ID or a [`modelOverrides`](#override-model-ids-per-version) mapping.
- The fallback model must resolve in your deployment. If you set `ANTHROPIC_DEFAULT_OPUS_MODEL`, flagged requests re-run on that model for every category that has a fallback; a biology flag on Opus 5 still ends with a refusal. If you don't set it, cybersecurity-flagged requests re-run on an Opus 4.8 entry in the provider's model list, and biology-flagged requests from Fable 5 on an Opus 5 entry.
If either model can't be identified, Claude Code does not switch automatically. The flagged request ends with a refusal message, and you can switch models with [`/model`](#setting-your-model) and retry. To enable automatic fallback on these providers, set `ANTHROPIC_DEFAULT_FABLE_MODEL` to your Fable 5 model ID and `ANTHROPIC_DEFAULT_OPUS_MODEL` to your Opus 4.8 model ID.
If either model can't be identified, Claude Code does not switch automatically. The flagged request ends with a refusal message, and you can switch models with [`/model`](#setting-your-model) and retry. Setting `ANTHROPIC_DEFAULT_FABLE_MODEL` to your Fable 5 model ID enables Fable 5 recognition. Setting `ANTHROPIC_DEFAULT_OPUS_MODEL` to an Opus model ID gives the flagged categories a fallback target, unless the pin names a model outside the Opus family or the model that refused; then Claude Code doesn't switch and the refusal stands.
#### Security research and biology workloads
Workloads in offensive security or biology, including penetration testing, Capture the Flag (CTF) exercises, and biology-adjacent codebases, trigger fallback frequently, often on the first request. For substantive biology work, expect nearly all requests to reroute.
Workloads in offensive security or biology, including penetration testing, Capture the Flag (CTF) exercises, and biology-adjacent codebases, trigger fallback frequently, often on the first request. For substantive biology work on Fable 5, Claude Code moves the session to Opus 5 at the first flagged request, and later biology-flagged requests end in refusals there, because Opus 5 has no biology fallback. On Opus 5, you get those refusals from the first flagged request.
This is expected routing for these domains, not an account flag. If your organization needs Fable-class capability for this work, ask your Anthropic account team about trusted access programs.
@@ -429,16 +437,18 @@ The available effort levels depend on the model. Models not listed here do not s
| Model | Levels |
| :- | :- |
| Fable 5 | `low`, `medium`, `high`, `xhigh`, `max` |
| Sonnet 5, Opus 4.8, and Opus 4.7 | `low`, `medium`, `high`, `xhigh`, `max` |
| Opus 5, Sonnet 5, Opus 4.8, and Opus 4.7 | `low`, `medium`, `high`, `xhigh`, `max` |
| Opus 4.6 and Sonnet 4.6 | `low`, `medium`, `high`, `max` |
If you set a level the active model does not support, Claude Code falls back to the highest supported level at or below the one you set. For example, `xhigh` runs as `high` on Opus 4.6. Your organization can also cap which levels are available for a model; see [Organization effort limits](#organization-effort-limits).
The default effort is `high` on Fable 5, Sonnet 5, Opus 4.8, Opus 4.6, and Sonnet 4.6, and `xhigh` on Opus 4.7.
The default effort is `high` on every model that supports effort, except Opus 4.7, which defaults to `xhigh`.
When you first run Fable 5, Opus 4.8, or Opus 4.7, Claude Code applies that model's default effort even if you previously set a different level for another model, and holds it across sessions until you make an explicit effort choice, such as running `/effort` in an interactive session or launching with `--effort`. Opus 5 has no such hold: a level you previously set carries over.
When you first run Fable 5, Opus 4.8, or Opus 4.7, Claude Code applies that model's default effort even if you previously set a different level for another model: `high` on Fable 5 and Opus 4.8, and `xhigh` on Opus 4.7. Run `/effort` again to choose a different level after switching. That default is held across sessions until you make an explicit effort choice, such as running `/effort` in an interactive session or launching with `--effort`.
`low`, `medium`, `high`, and `xhigh` persist across sessions when you set them in an interactive session. `max` provides the deepest reasoning and applies to the current session only, except when set through the `CLAUDE_CODE_EFFORT_LEVEL` environment variable.
`low`, `medium`, `high`, and `xhigh` persist across sessions when you set them in an interactive session. A level set with `/effort` in [non-interactive mode](/docs/en/headless), with the `-p` flag, applies to the current session only and isn't saved as your default. A non-interactive `/effort` also can't release the model-default hold above: on Fable 5, Opus 4.8, and Opus 4.7 it reports `Not applied` and the session stays at the model's default effort, so pass `--effort` at launch instead. `max` provides the deepest reasoning with no constraint on token spending and applies to the current session only, except when set through the `CLAUDE_CODE_EFFORT_LEVEL` environment variable.
A level set with `/effort` in [non-interactive mode](/docs/en/headless), with the `-p` flag, applies to the current session only and isn't saved as your default. It also can't release the model-default hold: while the hold is in force, a non-interactive `/effort` reports `Not applied`, so pass `--effort` at launch instead.
The `/effort` menu also offers `ultracode`. Ultracode is a Claude Code setting rather than a model effort level: it sends `xhigh` to the model and additionally has Claude orchestrate [dynamic workflows](/docs/en/workflows) for substantive tasks. It applies to the current session only.
@@ -462,8 +472,8 @@ Each level trades token spend against capability. The default suits most coding
| :- | :- |
| `low` | Reserve for short, scoped, latency-sensitive tasks that are not intelligence-sensitive |
| `medium` | Reduces token usage for cost-sensitive work that can trade off some intelligence |
| `high` | Balances token usage and intelligence. Default on Fable 5, Sonnet 5, Opus 4.8, Opus 4.6, and Sonnet 4.6 |
| `xhigh` | Deeper reasoning at higher token spend. Default on Opus 4.7 |
| `high` | Balances token usage and intelligence. The default on every model except Opus 4.7 |
| `xhigh` | Deeper reasoning at higher token spend. The default on Opus 4.7 |
| `max` | Can improve performance on demanding tasks but may show diminishing returns and is prone to overthinking. Test before adopting broadly |
| `ultracode` | A Claude Code setting that plans a [dynamic workflow](/docs/en/workflows) for each substantive task with `xhigh` per-message reasoning. Session-only |
@@ -516,7 +526,9 @@ Thinking output is collapsed by default. Press `Ctrl+O` to toggle verbose mode a
Fable 5, Sonnet 5, Opus 4.6 and later, and Sonnet 4.6 support a [1 million token context window](https://platform.claude.com/docs/en/build-with-claude/context-windows#context-window-sizes-by-model) for long sessions with large codebases.
Availability varies by model and plan. On the Anthropic API, Fable 5, Sonnet 5, Opus 4.8, and Opus 4.7 always run with the 1M window. On Max, Team, and Enterprise plans, Opus is automatically upgraded to 1M context with no additional configuration. This applies to both Team Standard and Team Premium seats. Sonnet 4.6 with 1M context is not part of the automatic upgrade and requires [usage credits](https://support.claude.com/en/articles/12429409-extra-usage-for-paid-claude-plans) on every subscription plan, including Max.
Availability varies by model and plan. On the Anthropic API, Fable 5, Sonnet 5, and Opus 4.7 and later always run with the 1M window.
On Max, Team, and Enterprise plans, including both Team Standard and Team Premium seats, Opus is automatically upgraded to 1M context with no additional configuration. Sonnet 4.6 with 1M context is not part of the automatic upgrade and requires [usage credits](https://support.claude.com/en/articles/12429409-extra-usage-for-paid-claude-plans) on every subscription plan, including Max.
| Plan | Opus with 1M context | Sonnet 4.6 with 1M context |
| - | - | - |
@@ -564,14 +576,18 @@ Use `ANTHROPIC_CUSTOM_MODEL_OPTION` to add a single custom entry to the `/model`
This example sets all three variables to make a gateway-routed Opus deployment selectable. Claude Code reads environment variables at startup, so run the exports before launching `claude`, or restart an existing session to pick them up:
```bash
export ANTHROPIC_CUSTOM_MODEL_OPTION="my-gateway/claude-opus-4-8"
export ANTHROPIC_CUSTOM_MODEL_OPTION="my-gateway/claude-opus-5"
export ANTHROPIC_CUSTOM_MODEL_OPTION_NAME="Opus via Gateway"
export ANTHROPIC_CUSTOM_MODEL_OPTION_DESCRIPTION="Custom deployment routed through the internal LLM gateway"
```
The custom entry appears at the bottom of the `/model` picker. `ANTHROPIC_CUSTOM_MODEL_OPTION_NAME` and `ANTHROPIC_CUSTOM_MODEL_OPTION_DESCRIPTION` are optional. If omitted, the model ID is used as the name and the description defaults to `Custom model (<model-id>)`.
Claude Code skips validation for the model ID set in `ANTHROPIC_CUSTOM_MODEL_OPTION`, so you can use any string your API endpoint accepts. When [`availableModels`](#restrict-model-selection) is set, include the custom model ID in the allowlist as well: the custom entry is filtered from the picker and a `--model` selection of it is rejected like any other excluded model. A custom ID that embeds a family name, such as `my-gateway/claude-opus-4-8`, counts as a specific entry for that family and disables its wildcard, so also list the versions you intend to keep selectable. See [Merge behavior](#merge-behavior).
Claude Code skips validation for the model ID set in `ANTHROPIC_CUSTOM_MODEL_OPTION`, so you can use any string your API endpoint accepts.
When [`availableModels`](#restrict-model-selection) is set, include the custom model ID in the allowlist as well. Otherwise the custom entry is filtered from the picker, and a `--model` selection of it is rejected like any other excluded model.
A custom ID that embeds a family name, such as `my-gateway/claude-opus-5`, counts as a specific entry for that family and disables its wildcard, so also list the versions you intend to keep selectable. See [Merge behavior](#merge-behavior).
## Environment variables
@@ -193,7 +193,7 @@ Auto mode is available only when your account meets all of these requirements:
- **Plan**: All plans.
- **Owner**: on Team and Enterprise, an Owner must enable it in [Claude Code admin settings](https://claude.ai/admin-settings/claude-code) before users can turn it on. Administrators can also turn auto mode off by setting `permissions.disableAutoMode` to `"disable"` in [managed settings](/docs/en/permissions#managed-settings). For the desktop app's Code tab, `disableAutoMode` is the organization-level control, and the admin settings toggle doesn't apply.
- **Model**: on the Anthropic API and [Claude Platform on AWS](/docs/en/claude-platform-on-aws), Claude Opus 4.6 or later, Sonnet 4.6 or later, or [Fable 5](/docs/en/model-config#work-with-fable-5). On Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, and signed-in [Claude apps gateway](/docs/en/claude-apps-gateway) sessions, only Claude Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5. Older models, including Sonnet 4.5, Opus 4.5, Haiku, and claude-3 models, are not supported on any provider.
- **Model**: on the Anthropic API and [Claude Platform on AWS](/docs/en/claude-platform-on-aws), Claude Opus 4.6 or later, Sonnet 4.6 or later, or [Fable 5](/docs/en/model-config#work-with-fable-5). On Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, and signed-in [Claude apps gateway](/docs/en/claude-apps-gateway) sessions, only Claude Sonnet 5, Opus 4.7 or later, and Fable 5. Older models, including Sonnet 4.5, Opus 4.5, Haiku, and claude-3 models, are not supported on any provider.
- **Provider**: available by default on the Anthropic API, Claude Platform on AWS, Amazon Bedrock, Google Cloud's Agent Platform, Microsoft Foundry, and signed-in Claude apps gateway sessions. In v2.1.158 through v2.1.206, auto mode was off on all of these providers except the Anthropic API and Claude Platform on AWS until you set `CLAUDE_CODE_ENABLE_AUTO_MODE=1`; v2.1.207 removed the requirement.
If Claude Code reports auto mode as unavailable, one of these requirements is unmet; this is not a transient outage. A separate message that names a model and says auto mode "cannot determine the safety" of an action means a classifier request failed; that failure is usually transient, but on Amazon Bedrock it can repeat until your account can invoke the named model. See the [error reference](/docs/en/errors#auto-mode-cannot-determine-the-safety-of-an-action) for the causes and what to do.
@@ -202,7 +202,7 @@ If you set `defaultMode: "auto"` in [settings](/docs/en/settings#available-setti
Auto mode on Bedrock, Agent Platform, or Foundry
On [Amazon Bedrock](/docs/en/amazon-bedrock), [Google Cloud's Agent Platform](/docs/en/google-vertex-ai), [Microsoft Foundry](/docs/en/microsoft-foundry), and signed-in [Claude apps gateway](/docs/en/claude-apps-gateway) sessions, auto mode appears in the `Shift+Tab` cycle by default. Appearing in the cycle doesn't change the mode a session starts in: sessions still start in your [`defaultMode`](/docs/en/settings#available-settings), which is Manual unless you change it. Only Claude Sonnet 5, Opus 4.7, Opus 4.8, and Fable 5 are supported on these providers.
On [Amazon Bedrock](/docs/en/amazon-bedrock), [Google Cloud's Agent Platform](/docs/en/google-vertex-ai), [Microsoft Foundry](/docs/en/microsoft-foundry), and signed-in [Claude apps gateway](/docs/en/claude-apps-gateway) sessions, auto mode appears in the `Shift+Tab` cycle by default. Appearing in the cycle doesn't change the mode a session starts in: sessions still start in your [`defaultMode`](/docs/en/settings#available-settings), which is Manual unless you change it. Only Claude Sonnet 5, Opus 4.7 or later, and Fable 5 are supported on these providers.
To make auto mode the default starting mode, set `"permissions": {"defaultMode": "auto"}` in user or managed settings.
@@ -70,7 +70,7 @@ Each model has its own cache. Switching with [`/model`](/docs/en/model-config#se
The [`opusplan` model setting](/docs/en/model-config#opusplan-model-setting) resolves to Opus during plan mode and Sonnet during execution, so each plan-mode toggle is a model switch and starts a fresh cache.
[Automatic model fallback](/docs/en/model-config#automatic-model-fallback) on Fable 5 is also a model switch. When a safety classifier flags a request, Claude Code re-runs it on the default Opus model and the session continues there.
[Automatic model fallback](/docs/en/model-config#automatic-model-fallback) on Fable 5 and Opus 5 is also a model switch. When a safety classifier flags a request and the flagged category has a fallback model, Claude Code re-runs the request on that model and the session continues there.
### Changing effort level
@@ -202,7 +202,7 @@ Your status line command receives this JSON structure via stdin:
"prompt_id": "550e8400-e29b-41d4-a716-446655440000",
"transcript_path": "/path/to/transcript.jsonl",
"model": {
"id": "claude-opus-4-8",
"id": "claude-opus-5",
"display_name": "Opus"
},
"workspace": {
@@ -247,7 +247,7 @@ The following fields can be used in the YAML frontmatter. Only `name` and `descr
| `description` | Yes | When Claude should delegate to this subagent |
| `tools` | No | [Tools](#available-tools) the subagent can use. Inherits every tool available to subagents if omitted. If no entry in the list resolves to a tool, the subagent usually [fails to launch](/docs/en/errors#agent-would-be-spawned-with-zero-tools) with an error naming the entries. To preload Skills into context, use the `skills` field rather than listing `Skill` here |
| `disallowedTools` | No | Tools to deny, removed from inherited or specified list |
| `model` | No | [Model](#choose-a-model) to use: `sonnet`, `opus`, `haiku`, `fable`, a full model ID (for example, `claude-opus-4-8`), or `inherit`. Defaults to `inherit` |
| `model` | No | [Model](#choose-a-model) to use: `sonnet`, `opus`, `haiku`, `fable`, a full model ID (for example, `claude-opus-5`), or `inherit`. Defaults to `inherit` |
| `permissionMode` | No | [Permission mode](#permission-modes): `default`, `acceptEdits`, `auto`, `dontAsk`, `bypassPermissions`, `plan`, or `manual` as an alias for `default`. The `manual` alias requires Claude Code v2.1.200 or later. Ignored for [plugin subagents](#choose-the-subagent-scope) |
| `maxTurns` | No | Maximum number of agentic turns before the subagent stops |
| `skills` | No | [Skills](/docs/en/skills) to preload into the subagent's context at startup. The full skill content is injected, not only the description. Subagents can still invoke unlisted project, user, and plugin skills through the Skill tool |
@@ -265,7 +265,7 @@ The following fields can be used in the YAML frontmatter. Only `name` and `descr
The `model` field controls which [AI model](/docs/en/model-config) the subagent uses:
- **Model alias**: use one of the available aliases: `sonnet`, `opus`, `haiku`, or `fable`
- **Full model ID**: use a full model ID such as `claude-opus-4-8` or `claude-sonnet-5`. Accepts the same values as the `--model` flag
- **Full model ID**: use a full model ID such as `claude-opus-5` or `claude-sonnet-5`. Accepts the same values as the `--model` flag
- **inherit**: use the same model as the main conversation
- **Omitted**: defaults to `inherit` and uses the same model as the main conversation