249 pages for sonnet.
Titles and paths first, then pages whose text carries it. Each row opens that page as this site last read it.
effort
Claude Developer Platform · in the page
build-with-claude/effort
…4-7 - claude-opus-4-6 - claude-opus-4-5-20251101 - claude-sonnet-5-5 - claude-sonnet-5 - claude-sonnet-4-6 supportedPlatforms: Claude API: ga Claude Platform on AWS: ga…
extended-thinking
Claude Developer Platform · in the page
build-with-claude/extended-thinking
…H "content-type: application/json" \ -d '{ "model": "claude-sonnet-4-6", "max_tokens": 16000, "thinking": { "type": "enabled", "budget_tokens": 10000 },…
fallback-credit
Claude Developer Platform · in the page
build-with-claude/fallback-credit
…aude Fable 5, Claude Opus 5.5, Claude Opus 5, Claude Opus 4.8, Claude Sonnet 5.5, and Claude Sonnet 5, the `context-1m-2025-08-07` beta header has no effect. To keep the two requests identical, omit t…
handling-stop-reasons
Claude Developer Platform · in the page
build-with-claude/handling-stop-reasons
…If you encounter `refusal` stop reasons frequently while using Claude Sonnet 4.5 or Claude Opus 4.1 (the latter [retired, except on Bedrock and Google Cloud](https://platform.claude.com/docs/en/about-…
mid-conversation-system-messages
Claude Developer Platform · in the page
build-with-claude/mid-conversation-system-messages
…asswing), Claude Opus 5.5, Claude Opus 4.8, Claude Opus 5, and Claude Sonnet 5.5. No beta header is required for mid-conversation system messages. This feature is not available on Claude Sonnet 5. Use…
multilingual-support
Claude Developer Platform · in the page
build-with-claude/multilingual-support
…ish performance (100%): | Language | Claude Sonnet 4.51 | Claude Haiku 4.51 | | --------------------------------- | ------------------ | ----------------- | | English (baseli…
preserved-thinking
Claude Developer Platform · in the page
build-with-claude/preserved-thinking
…m/docs/en/build-with-claude/preserved-thinking#prefix-check). Claude Sonnet 5.5's thinking blocks are also tied to the account that produced them. See [Thinking blocks stay with the account that prod…
Request 2 caches its request content (not the response)
Claude Developer Platform · in the page
build-with-claude/prompt-caching
…$30 / MTok | $1.50 / MTok | $75 / MTok | | Claude Sonnet 5.5 | $…
claude-prompting-best-practices
Claude Developer Platform · in the page
build-with-claude/prompt-engineering/claude-prompting-best-practices
…ude Opus 5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, Claude Sonnet 5.5, Claude Sonnet 5, Claude Sonnet 4.6, and Claude Haiku 4.5. The page is organized in three parts: * **[Model-specific g…
Delivering work
Claude Developer Platform · in the page
build-with-claude/prompt-engineering/prompting-claude-fable-5-1
…w`, Claude Fable 5.1 is often competitive with Claude Opus and Claude Sonnet models on cost per task while scoring higher, so include it in the comparison wherever you'd otherwise run a smaller model…
refusals-and-fallback
Claude Developer Platform · in the page
build-with-claude/refusals-and-fallback
…description: How Claude Fable models, Claude Opus models, and Claude Sonnet 5.5 return classifier refusals and how to retry refused requests on a fallback model. --- Claude Fable 5.1, Claude Fable 5…
structured-outputs
Claude Developer Platform · in the page
build-with-claude/structured-outputs
…ude-opus-4-8 - claude-opus-4-7 - claude-opus-4-6 - claude-sonnet-5-5 - claude-sonnet-5 - claude-sonnet-4-6 - claude-sonnet-4-5-20250929 - claude-opus-4-5-20251101 - cla…
task-budgets
Claude Developer Platform · in the page
build-with-claude/task-budgets
…laude-opus-5 - claude-opus-4-8 - claude-opus-4-7 - claude-sonnet-5-5 --- Task budgets let you tell Claude how many tokens it has for a full agentic loop, including thinking, tool calls, t…
thinking
Claude Developer Platform · in the page
build-with-claude/thinking
…| 400 error | | Claude Sonnet 5.5 | Adaptive thinking | Adaptive thinking | 400 error | Up-front thinking off at `high` effo…
thinking-troubleshooting
Claude Developer Platform · in the page
build-with-claude/thinking-troubleshooting
…400 error; any value not listed as rejected is accepted. Only Claude Sonnet 5.5 accepts `"between_tools"`, and it takes that value in place of `"disabled"`. | Model | Thinking types…
working-with-messages
Claude Developer Platform · in the page
build-with-claude/working-with-messages
…asswing), Claude Opus 5.5, Claude Opus 4.8, Claude Opus 5, and Claude Sonnet 5.5, you can include messages with `"role": "system"` after a user turn (subject to [placement rules](https://platform.clau…
API usage primer for Claude
Claude Developer Platform · in the page
claude_api_primer
…Previous Opus model: Claude Opus 5: claude-opus-5 Smart model: Claude Sonnet 5.5: claude-sonnet-5-5 Previous Sonnet model: Claude Sonnet 5: claude-sonnet-5 For fast, cost-effective tasks: Claude Haiku…
apple-foundation-models
Claude Developer Platform · in the page
cli-sdks-libraries/libraries/apple-foundation-models
…ClaudeForFoundationModels let model = ClaudeLanguageModel( name: .sonnet5, auth: .apiKey(ProcessInfo.processInfo.environment["ANTHROPIC_API_KEY"] ?? "") ) let session = LanguageModelSession(mod…
openai-sdk
Claude Developer Platform · in the page
cli-sdks-libraries/libraries/openai-sdk
…thon response = client.chat.completions.create( model="claude-sonnet-4-6", messages=[{"role": "user", "content": "Who are you?"}], extra_body={"thinking": {"type": "enabled", "budg…
home
Claude Developer Platform · in the page
home
…nd knowledge work* — Complex projects · Agents · Coding * [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) (`claude-sonnet-5-5`) — New — *The best combination of…
intro
Claude Developer Platform · in the page
intro
…ng and knowledge work* — Complex projects · Agents · Coding * [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) (`claude-sonnet-5-5`) — New — *The best combination of…
data-residency
Claude Developer Platform · in the page
manage-claude/data-residency
…ater models. Requests with `inference_geo` on Claude Opus 4.5, Claude Sonnet 4.5, Claude Haiku 4.5, or earlier models return a 400 error. <Note> The `inference_geo` parameter is available on the Cl…
inference-hooks-endpoint
Claude Developer Platform · in the page
manage-claude/inference-hooks-endpoint
…ssion_id": "22222222-2222-2222-2222-222222222222", "model": "claude-sonnet-4-5", "messages": [ { "role": "user", "content": [ { "type": "text", "text":…
rate-limits-api
Claude Developer Platform · in the page
manage-claude/rate-limits-api
…s that counts against the group, including dated IDs (such as `claude-sonnet-4-5-20250929`) and undated aliases (such as `claude-sonnet-4-5`). Look up any model string you pass to the Messages API and…
First request
Claude Developer Platform · in the page
manage-claude/usage-cost-api
…ls released before February 2026 (prior to Claude Opus 4.6 and Claude Sonnet 4.6) don't support the `inference_geo` request parameter, so their usage reports return `"not_available"` for this dimensio…
dreams
Claude Developer Platform · in the page
managed-agents/dreams
…s-5`, `claude-fable-5`, `claude-opus-4-8`, `claude-opus-4-7`, `claude-sonnet-5`, and `claude-sonnet-4-6` are supported. You can optionally pass `instructions` to steer the dreaming process. See [Steer…
events-and-streaming
Claude Developer Platform · in the page
managed-agents/events-and-streaming
…Mythos 5, Claude Opus 5.5, Claude Opus 5, Claude Opus 4.8, and Claude Sonnet 5.5. If the agent's primary model does not support mid-conversation system injection, the event is rejected with a `model_d…
multiagent-orchestration
Claude Developer Platform · in the page
managed-agents/multiagent-orchestration
…/json" \ -d '{ "name": "Backend engineer", "model": "claude-sonnet-5", "system": "You implement backend features end to end. Consult the advisor before major backend design decisions.",…
reference
Claude Developer Platform · in the page
managed-agents/reference
…Mythos 5, Claude Opus 5.5, Claude Opus 5, Claude Opus 4.8, and Claude Sonnet 5.5. On an unsupported primary model the event is rejected with `model_does_not_support_mid_conversation_system`. | </Tab…
sessions
Claude Developer Platform · in the page
managed-agents/sessions
…th_overrides", "id": "$AGENT_ID", "model": {"id": "claude-sonnet-5"}, "system": null }, "environment_id": "$ENVIRONMENT_ID" } EOF ``` ```bash CLI # The response's…
overview
Claude Developer Platform · in the page
models/fable-5-1/overview
…Adaptive (always on) | `medium` | Jun 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Fast | Ada…
overview
Claude Developer Platform · in the page
models/fable-5/overview
…Adaptive (always on) | `medium` | Jun 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
overview
Claude Developer Platform · in the page
models/haiku-4-5/overview
…Adaptive (always on) | `medium` | Jun 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Fast | Ada…
overview
Claude Developer Platform · in the page
models/mythos-5-1/overview
…Adaptive (always on) | `medium` | Jun 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Fast | Ada…
overview
Claude Developer Platform · in the page
models/mythos-5/overview
…Adaptive (always on) | `medium` | Jun 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
overview
Claude Developer Platform · in the page
models/opus-4-5/overview
…Extended | `high` | May 2025 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
overview
Claude Developer Platform · in the page
models/opus-4-6/overview
…(extended deprecated) | `high` | May 2025 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
overview
Claude Developer Platform · in the page
models/opus-4-7/overview
…Adaptive | `high` | Jan 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
overview
Claude Developer Platform · in the page
models/opus-4-8/overview
…Adaptive | `high` | Jan 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
migration-guide
Claude Developer Platform · in the page
models/opus-5-5/migration-guide
…ption: "Migrate to Claude Opus 5.5 from earlier Opus models or Claude Sonnet 5: request settings that return errors, thinking blocks in every response, and a checklist for each starting model." --- <…
overview
Claude Developer Platform · in the page
models/opus-5-5/overview
…Adaptive (always on) | `medium` | Jun 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Fast | Ada…
whats-new-opus-5-5
Claude Developer Platform · in the page
models/opus-5-5/whats-new-opus-5-5
…e Opus 5.5 reads thinking blocks from Claude Opus 5 and earlier Opus, Sonnet, and Haiku models, but not from Claude Fable or Claude Mythos models. On the Claude API, Claude Fable 5.1 and Claude Mythos…
overview
Claude Developer Platform · in the page
models/opus-5/overview
…Adaptive | `high` | May 2026 | | [Claude Sonnet 5.5](https://platform.claude.com/docs/en/models/sonnet-5-5/overview) | 1M | 128K | $2 / $10 | Adaptive…
Models overview
Claude Developer Platform · in the page
models/overview
…| Claude Sonnet 5.5 | Claude Haiku 4.5…
overview
Claude Developer Platform · in the page
release-notes/overview
…repository. </Tip> ### September 28, 2026 * We've launched **Claude Sonnet 5.5** (`claude-sonnet-5-5`). It's available on the Claude API, [Claude in Amazon Bedrock](https://platform.claude.com/docs/…
claude-fable-5
Claude Developer Platform · in the page
release-notes/system-prompts/claude-fable-5
…m. The most recent models are Claude Fable 5, Claude Opus 4.8, Claude Sonnet 4.6, and Claude Haiku 4.5, with model strings 'claude-fable-5', 'claude-opus-4-8', 'claude-sonnet-4-6', and 'claude-haiku-4…
claude-fable-5-1
Claude Developer Platform · in the page
release-notes/system-prompts/claude-fable-5-1
…m. The most recent models are Claude Fable 5.1, Claude Opus 5, Claude Sonnet 5, and Claude Haiku 4.5, with model strings 'claude-fable-5-1', 'claude-opus-5', 'claude-sonnet-5', and 'claude-haiku-4-5-2…
claude-haiku-3-5
Claude Developer Platform · in the page
release-notes/system-prompts/claude-haiku-3-5
…ily currently consists of Claude Haiku 3.5, Claude Opus 3, and Claude Sonnet 3.5. Claude Sonnet 3.5 is the most intelligent model. Claude Opus 3 excels at writing and complex tasks. Claude Haiku 3.5 i…
claude-haiku-4-5
Claude Developer Platform · in the page
release-notes/system-prompts/claude-haiku-4-5
…**Claude 4.5** family currently consists of **Claude Opus 4.5, Claude Sonnet 4.5, and Claude Haiku 4.5**. Claude Haiku 4.5 is the fastest model for quick questions. If the person asks, Claude can tel…
claude-opus-4
Claude Developer Platform · in the page
release-notes/system-prompts/claude-opus-4
…y. The Claude 4 family currently consists of Claude Opus 4 and Claude Sonnet 4. Claude Opus 4 is the most powerful model for complex challenges. If the person asks, Claude can tell them about the fol…