348 pages for opus.
Titles and paths first, then pages whose text carries it. Each row opens that page as this site last read it.
claude-sonnet-4
Claude Developer Platform · in the page
release-notes/system-prompts/claude-sonnet-4
…aude 4 model family. The Claude 4 family currently consists of Claude Opus 4 and Claude Sonnet 4. Claude Sonnet 4 is a smart, efficient model for everyday use. If the person asks, Claude can tell the…
claude-sonnet-4-5
Claude Developer Platform · in the page
release-notes/system-prompts/claude-sonnet-4-5
…odel family. The **Claude 4.5** family currently consists of **Claude Opus 4.5, Claude Sonnet 4.5, and Claude Haiku 4.5**. Claude Sonnet 4.5 is **a smart, efficient model for everyday use**. If the p…
claude-sonnet-4-6
Claude Developer Platform · in the page
release-notes/system-prompts/claude-sonnet-4-6
…yday use in the Claude 4.6 family (which currently consists of Claude Opus 4.6 and Claude Sonnet 4.6). If the person asks, Claude can tell them about the following products which allow access to Clau…
claude-sonnet-5
Claude Developer Platform · in the page
release-notes/system-prompts/claude-sonnet-5
…ble via an API and Claude Platform. The most recent models are Claude Opus 4.8, Claude Sonnet 5, and Claude Haiku 4.5, with model strings 'claude-opus-4-8', 'claude-sonnet-5', and 'claude-haiku-4-5-20…
claude-sonnet-5-5
Claude Developer Platform · in the page
release-notes/system-prompts/claude-sonnet-5-5
…Claude Platform. The most recent models are Claude Fable 5.1, Claude Opus 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',…
overview
Claude Developer Platform · in the page
release-notes/system-prompts/overview
…elease-notes/system-prompts/claude-sonnet-5-5" /> <Card id="claude-opus-5-5" title="Claude Opus 5.5" icon="file" href="https://platform.claude.com/docs/en/release-notes/system-prompts/claude-opus-5…
overview
Claude Developer Platform · in the page
resources/overview
…documentation of Claude Sonnet 5.5. </Card> <Card title="Claude Opus 5.5 System Card" icon="file" href="https://www.anthropic.com/claude-opus-5-5-system-card"> Detailed documentation of Clau…
develop-tests
Claude Developer Platform · in the page
test-and-evaluate/develop-tests
…message = client.messages.create( model="claude-opus-5-5", max_tokens=1024, messages=[{"role": "user", "content": prompt}], ) retu…
handle-streaming-refusals
Claude Developer Platform · in the page
test-and-evaluate/strengthen-guardrails/handle-streaming-refusals
…ges + [{"role": "user", "content": "Hello"}], model="claude-opus-5-5", ) as stream: for event in stream: # Check for refusal in message delta if e…
Escalate hard decisions with the advisor tool
Claude Code CLI · in the page
advisor
…ig#setting-your-model) instead, or see [how the advisor compares with opusplan and subagents](#compare-with-related-features) for other ways to get a second opinion. ## Enable the advisor You can se…
Configure your agent
Claude Code CLI · in the page
agent-sdk/configuration
…const options = { model: "claude-fable-5", fallbackModel: "claude-opus-5,claude-sonnet-5", }; ``` ```python Python theme={null} options = ClaudeAgentOptions( model="claude-fable-5", fallb…
Track cost and usage
Claude Code CLI · in the page
agent-sdk/cost-tracking
…ul when you run multiple models (for example, Haiku for subagents and Opus for the main agent) and want to see where tokens are going. Each entry's `costBasis` says which price table priced that mode…
Migrate to Claude Agent SDK
Claude Code CLI · in the page
agent-sdk/migration-guide
…t query, ClaudeCodeOptions options = ClaudeCodeOptions(model="claude-opus-4-7", permission_mode="acceptEdits") # AFTER (claude-agent-sdk) from claude_agent_sdk import query, ClaudeAgentOptions opti…
Agent SDK reference - Python
Claude Code CLI · in the page
agent-sdk/python
…Model override for this agent. Accepts an alias such as `"sonnet"`, `"opus"`, `"haiku"`, or `"inherit"`, or a full model ID. When you omit it, Claude Code picks the model in the [subagent model order]…
Subagents in the SDK
Claude Code CLI · in the page
agent-sdk/subagents
…Model override for this agent. Accepts an alias such as `'fable'`, `'opus'`, `'sonnet'`, `'haiku'`, `'inherit'`, or a full model ID. `'inherit'` uses the main model. When you omit it, Claude Code pic…
Track todos
Claude Code CLI · in the page
agent-sdk/todo-tracking
…NOTE] > > The following tools are available by default only on Claude Opus 4.7, Claude Sonnet 4.6, Claude Haiku 4.5, and earlier models. On every other model, including model IDs Claude Code doesn't r…
Scale to many tools with tool search
Claude Code CLI · in the page
agent-sdk/tool-search
…ud's Agent Platform, the SDK decides by model generation: * **Claude Opus 4.5, Sonnet 4.5, Haiku 4.5, and later**: tool search is on by default. * **Earlier Agent Platform models**: the SDK loads too…
Agent SDK reference - TypeScript
Claude Code CLI · in the page
agent-sdk/typescript
…or the rest of the session await q.applyFlagSettings({ model: "claude-opus-4-6" }); // Later: clear the override; the model resets to Claude Code's default await q.applyFlagSettings({ model: null });…
TypeScript SDK V2 session API (removed)
Claude Code CLI · in the page
agent-sdk/typescript-v2-preview
…esult = await unstable_v2_prompt("What is 2 + 2?", { model: "claude-opus-4-7" }); if (result.subtype === "success") { console.log(result.result); } ``` <details> <summary>See the same operation…
Orchestrate teams of Claude Code sessions
Claude Code CLI · in the page
agent-teams
…ue, Claude Code substitutes another model: * **Family alias such as `opus`**: On the Anthropic API and Claude Platform on AWS, Claude Code runs the teammate on the newest version of that family the a…
Manage multiple agents with agent view
Claude Code CLI · in the page
agent-view
…e one from a list: * **Model**: `/model <name>`, for example `/model opus` * **[Effort level](/docs/en/model-config#adjust-effort-level)**: `/effort` with `low`, `medium`, `high`, `xhigh`, or `max`,…
Claude Code on Amazon Bedrock
Claude Code CLI · in the page
amazon-bedrock
…multiple users. Without pinning, model aliases such as `sonnet` and `opus` resolve to Claude Code's built-in default for Amazon Bedrock, which can lag the newest release and may not yet be available…
Best practices for Claude Code
Claude Code CLI · in the page
best-practices
…ode for security vulnerabilities tools: Read, Grep, Glob, Bash model: opus --- You are a senior security engineer. Review code for: - Injection vulnerabilities (SQL, XSS, command injection) - Authenti…
Claude Code changelog
Claude Code CLI · in the page
changelog
…XT` is set and the model is an alias with the `[1m]` suffix, such as `opus[1m]` * Fixed the `prompt-caching-scope` beta header being sent behind custom `ANTHROPIC_BASE_URL` gateways and on Foundry, wh…
Claude apps gateway for Amazon Bedrock, Claude Platform on AWS, Google Cloud, and Microsoft Foundry
Claude Code CLI · in the page
claude-apps-gateway
…slated per upstream automatically. The built-in catalog # maps claude-opus-4-8 to us.anthropic.claude-opus-4-8 and so on for every # Bedrock-supported Claude model. Set false and add a `models:` list…
Claude apps gateway configuration
Claude Code CLI · in the page
claude-apps-gateway-config
…solated upstream serves: ```yaml theme={null} models: - id: claude-opus-restricted # a custom id, not a built-in model name upstream_model: bedrock-isolated: us.anthropic.claude-…
Deploy Claude apps gateway on AWS
Claude Code CLI · in the page
claude-apps-gateway-on-aws
…heme={null} models: # Include the served model's id, such as claude-opus-4-8, in each id so the gateway's spend meter can price it. - id: platform-claude-opus-4-8 upstream_model: bedrock…
Claude Code on Claude Platform on AWS
Claude Code CLI · in the page
claude-platform-on-aws
…me 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 relea…
Let Claude coordinate ongoing work with Projects
Claude Code CLI · in the page
claude-projects
…in **Project settings > General**. A new project runs every thread on Opus at high effort, which draws on your plan fastest; [Choose models and let Claude manage context](#choose-models-and-let-claude…
Scan your codebase for vulnerabilities
Claude Code CLI · in the page
claude-security
…lag certain requests, and Claude Code re-runs a flagged request on an Opus model through [automatic model fallback](/docs/en/model-config#automatic-model-fallback). This is expected. When the request…
CLI reference
Claude Code CLI · in the page
cli-reference
…ool](/docs/en/advisor) for this session with a model alias, `fable`, `opus`, or `sonnet`, or a full model ID. Takes precedence over the `advisorModel` setting for the session. `fable` requires [Fable…
Commands
Claude Code CLI · in the page
commands
…nd model for guidance at key moments during a task. Accepts `fable`, `opus`, `sonnet`, or a full model ID. `fable` requires [Fable access](/docs/en/advisor#choose-an-advisor-model). Without an argumen…
Communications kit
Claude Code CLI · in the page
communications-kit
…``markdown theme={null} 🎯 *Tip: Match the model to the moment* Using Opus to fix a typo burns compute. Using Haiku for a 12-file refactor is asking for a re-do. Claude Code runs on the same models a…
Explore the context window
Claude Code CLI · in the page
context-window
…a smaller conversation, Fable models, Sonnet 5 and later, Haiku 5.5, Opus 4.6 and later, and Sonnet 4.6 support a 1 million token context window. See [Extended context](/docs/en/model-config#extended…
Manage costs effectively
Claude Code CLI · in the page
costs
…ows when the window resets. After the model-specific "You've hit your Opus limit" or "You've hit your Sonnet limit" message, switching to a model outside that family with `/model` does keep the develo…
Desktop application
Claude Code CLI · in the page
desktop
…de is available to all users on the Anthropic API and requires Claude Opus 4.6 or later, Sonnet 4.6 or later, Haiku 5.5, or a [Fable model](/docs/en/model-config#work-with-fable). Organization adminis…
Environment variables
Claude Code CLI · in the page
env-vars
…| | `ANTHROPIC_DEFAULT_OPUS_MODEL` | Model ID that the `opus` alias resolves to, and that `opusplan` uses while Plan Mode is act…
Error reference
Claude Code CLI · in the page
errors
…rs` | [Server errors](#api-error-repeated-529-overloaded-errors) | | `Opus is experiencing high load` / `Fable is experiencing high load` | [Server errors](#api-error-repeated-529-overloaded-errors) |…
Speed up responses with fast mode
Claude Code CLI · in the page
fast-mode
# Speed up responses with fast mode > Get faster Opus responses in Claude Code by toggling fast mode. > [!NOTE] > > Fast mode is in [research preview](#research-preview). The feature, pricing, and a…
Feature availability
Claude Code CLI · in the page
feature-availability
…t Platform, tool search isn't supported on models earlier than Claude Opus 4.5, Claude Sonnet 4.5, and Claude Haiku 4.5 * **Subagents**: when the main conversation runs Fable, the built-in [Explore su…
Claude Code GitHub Actions
Claude Code CLI · in the page
github-actions
…and open issues" claude_args: | --model claude-opus-5-5 --allowedTools "mcp__github__list_commits,mcp__github__list_issues" ``` ## Best practices ### Define projec…
Glossary
Claude Code CLI · in the page
glossary
…effort is faster and cheaper. Effort is supported on Fable models, on Opus 4.6 and later, on Sonnet 4.6 and later, and on Haiku 5.5. Learn more: [Adjust effort level](/docs/en/model-config#adjust-eff…
Claude Code on Google Cloud's Agent Platform
Claude Code CLI · in the page
google-vertex-ai
…mcp-tool-search) and upfront loading by model generation: * **Claude Opus 4.5, Sonnet 4.5, Haiku 4.5, and later**: Claude Code enables tool search by default. * **Earlier models**: Claude Code loads…
Hooks reference
Claude Code CLI · in the page
hooks
…es to, as described under [PreModelSwitch](#premodelswitch) | `claude-opus-5`, `claude-opus-4-6\|claude-opus-5`, `.*opus.*` | | `SubagentStop` | agent type | same values as `SubagentStart` | | `Config…
Automate actions with hooks
Claude Code CLI · in the page
hooks-guide
…ribed under [PreModelSwitch](/docs/en/hooks#premodelswitch) | `claude-opus-5`, `claude-opus-4-6\|claude-opus-5`, `.*opus.*` | | `SubagentStop` | agent type | same values as `SubagentStart` | | `Config…
How Claude Code works
Claude Code CLI · in the page
how-claude-code-works
…able with different tradeoffs. Sonnet handles most coding tasks well. Opus provides stronger reasoning for complex architectural decisions. Switch with `/model` during a session or start with `claude…
Interactive mode
Claude Code CLI · in the page
interactive-mode
…thinking | Enable or disable extended thinking mode. Has no effect on Opus 5.5, Sonnet 5.5, Haiku 5.5, or the Fable models, which always use extended thinking. Works on macOS without configuring Optio…
Connect Claude Code to an LLM gateway
Claude Code CLI · in the page
llm-gateway-connect
…) lists the exact names. * **Model versions**: pin `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, and `ANTHROPIC_DEFAULT_HAIKU_MODEL` as in [Pin model versions](/docs/en/google-vert…
Claude Code gateway compatibility guide
Claude Code CLI · in the page
llm-gateway-protocol
…quests by default | The provider's form, such as `us.anthropic.claude-opus-4-8` on Amazon Bedrock | Anthropic IDs, such as `claude-opus-4-8` | Anthropic IDs | | `anthropic-beta` values sent | The subs…
Roll out an LLM gateway for your organization
Claude Code CLI · in the page
llm-gateway-rollout
…installed version doesn't recognize, such as the gateway alias `prod-opus`, runs on default assumptions for [adaptive reasoning](/docs/en/model-config#adaptive-reasoning-and-fixed-thinking-budgets),…