--- title: Extended Thinking product: vercel url: /docs/ai-gateway/sdks-and-apis/anthropic-messages-api/reasoning canonical_url: "https://vercel.com/docs/ai-gateway/sdks-and-apis/anthropic-messages-api/reasoning" last_updated: 2026-07-28 type: conceptual prerequisites: - /docs/ai-gateway/sdks-and-apis/anthropic-messages-api - /docs/ai-gateway/sdks-and-apis related: - /docs/ai-gateway/sdks-and-apis/anthropic-messages-api/messages - /docs/ai-gateway/models-and-providers/reasoning - /docs/ai-gateway/sdks-and-apis/openai-chat-completions/reasoning - /docs/ai-gateway/models-and-providers/reasoning/anthropic - /docs/ai-gateway/sdks-and-apis/anthropic-messages-api/advanced summary: Configure how much Claude thinks before answering, using the Anthropic Messages API thinking parameter. install_vercel_plugin: npx plugins add vercel/vercel-plugin --- # Extended Thinking Anthropic calls reasoning **extended thinking**. Configure it with the `thinking` parameter on a [Messages](/docs/ai-gateway/sdks-and-apis/anthropic-messages-api/messages) request. Other API surfaces call the same capability reasoning: see [Reasoning](/docs/ai-gateway/models-and-providers/reasoning) for the cross-provider reference, or [Chat Completions reasoning](/docs/ai-gateway/sdks-and-apis/openai-chat-completions/reasoning) for the OpenAI-shaped equivalent. ## Related pages > **For AI agents:** Follow these links to understand how this page connects to the rest of the Vercel ecosystem. For the full cross-link map (inbound, outbound, prerequisites, and semantic neighbors), see the .graph.md link below. - [Anthropic](https://ai-sdk.dev/providers/ai-sdk-providers/anthropic?from=related) - [Reasoning](https://ai-sdk.dev/docs/ai-sdk-core/reasoning?from=related) - [Get started with Claude 3.7 Sonnet](https://ai-sdk.dev/cookbook/guides/sonnet-3-7?from=related) - [Reasoning](https://vercel.com/docs/ai-gateway/sdks-and-apis/openresponses/reasoning?from=related) — Control how much a reasoning model thinks before answering with the OpenResponses API. - [Google / Vertex](https://vercel.com/docs/ai-gateway/models-and-providers/reasoning/google?from=related) — Configure thinking for Google Gemini and Gemma models with the AI SDK and AI Gateway. - [Amazon Bedrock](https://vercel.com/docs/ai-gateway/models-and-providers/reasoning/amazon-bedrock?from=related) — Configure reasoning for models hosted on Amazon Bedrock with the AI SDK and AI Gateway. - [Reasoning](https://vercel.com/docs/ai-gateway/sdks-and-apis/responses/reasoning?from=related) — Control how much a model thinks before answering with the OpenAI Responses API. - [Python](https://vercel.com/docs/ai-gateway/sdks-and-apis/python?from=related) — Use the AI Gateway with Python through OpenAI or Anthropic SDKs with full streaming, tool calling, and async support. Full cross-link map for this page: [/docs/ai-gateway/sdks-and-apis/anthropic-messages-api/reasoning.graph.md](/docs/ai-gateway/sdks-and-apis/anthropic-messages-api/reasoning.graph.md) Configure thinking for models that support chain-of-thought reasoning. The `thinking` parameter allows you to control how reasoning tokens are generated and returned. There are two modes: - **Adaptive thinking**: Set `thinking: { type: 'adaptive' }`. The model decides when and how much to think. Available on Claude 4.6 and later. Required on Claude Opus 4.7 and later. - **Extended thinking with a token budget**: Set `thinking: { type: 'enabled', budget_tokens: N }` for a fixed token budget. Available on Claude 4.6 and earlier. Deprecated on Claude 4.6. Returns a 400 error on Claude Opus 4.7 and later. See the [Anthropic reasoning reference](/docs/ai-gateway/models-and-providers/reasoning/anthropic#supported-models) for the full model support matrix. The `thinking` parameter works with any reasoning model, not just Anthropic models. AI Gateway maps it to the target provider's native reasoning configuration, so you can set a thinking budget on a request to an OpenAI or Google model too. ## Adaptive thinking (Claude 4.6 and later) On Claude Opus 4.7 and later, set `display: 'summarized'` to receive thinking text, which is omitted by default: #### cURL ```bash filename="adaptive-thinking.sh" curl -X POST "https://ai-gateway.vercel.sh/v1/messages" \ -H "Authorization: Bearer $AI_GATEWAY_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "anthropic/claude-opus-5", "max_tokens": 2048, "thinking": { "type": "adaptive", "display": "summarized" }, "messages": [ { "role": "user", "content": "Explain quantum entanglement in simple terms." } ] }' ``` #### TypeScript ```typescript filename="thinking-adaptive.ts" import Anthropic from '@anthropic-ai/sdk'; const apiKey = process.env.AI_GATEWAY_API_KEY || process.env.VERCEL_OIDC_TOKEN; const anthropic = new Anthropic({ apiKey, baseURL: 'https://ai-gateway.vercel.sh', }); const message = await anthropic.messages.create({ model: 'anthropic/claude-opus-5', max_tokens: 2048, thinking: { type: 'adaptive', display: 'summarized', }, messages: [ { role: 'user', content: 'Explain quantum entanglement in simple terms.', }, ], }); for (const block of message.content) { if (block.type === 'thinking') { console.log('🧠 Thinking:', block.thinking); } else if (block.type === 'text') { console.log('💬 Response:', block.text); } } ``` #### Python ```python filename="thinking_adaptive.py" import os import anthropic api_key = os.getenv('AI_GATEWAY_API_KEY') or os.getenv('VERCEL_OIDC_TOKEN') client = anthropic.Anthropic( api_key=api_key, base_url='https://ai-gateway.vercel.sh' ) message = client.messages.create( model='anthropic/claude-opus-5', max_tokens=2048, thinking={ 'type': 'adaptive', 'display': 'summarized', }, messages=[ { 'role': 'user', 'content': 'Explain quantum entanglement in simple terms.' } ], ) for block in message.content: if block.type == 'thinking': print('🧠 Thinking:', block.thinking) elif block.type == 'text': print('💬 Response:', block.text) ``` ## Extended thinking with a token budget (Claude 4.6 and earlier) For pre-4.7 models, use `type: 'enabled'` with a `budget_tokens` value: #### cURL ```bash filename="extended-thinking.sh" curl -X POST "https://ai-gateway.vercel.sh/v1/messages" \ -H "Authorization: Bearer $AI_GATEWAY_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "anthropic/claude-sonnet-4.5", "max_tokens": 8192, "thinking": { "type": "enabled", "budget_tokens": 5000 }, "messages": [ { "role": "user", "content": "Explain quantum entanglement in simple terms." } ] }' ``` #### TypeScript ```typescript filename="thinking.ts" import Anthropic from '@anthropic-ai/sdk'; const apiKey = process.env.AI_GATEWAY_API_KEY || process.env.VERCEL_OIDC_TOKEN; const anthropic = new Anthropic({ apiKey, baseURL: 'https://ai-gateway.vercel.sh', }); const message = await anthropic.messages.create({ model: 'anthropic/claude-sonnet-4.5', max_tokens: 8192, thinking: { type: 'enabled', budget_tokens: 5000, }, messages: [ { role: 'user', content: 'Explain quantum entanglement in simple terms.', }, ], }); for (const block of message.content) { if (block.type === 'thinking') { console.log('🧠 Thinking:', block.thinking); } else if (block.type === 'text') { console.log('💬 Response:', block.text); } } ``` #### Python ```python filename="thinking.py" import os import anthropic api_key = os.getenv('AI_GATEWAY_API_KEY') or os.getenv('VERCEL_OIDC_TOKEN') client = anthropic.Anthropic( api_key=api_key, base_url='https://ai-gateway.vercel.sh' ) message = client.messages.create( model='anthropic/claude-sonnet-4.5', max_tokens=8192, thinking={ 'type': 'enabled', 'budget_tokens': 5000, }, messages=[ { 'role': 'user', 'content': 'Explain quantum entanglement in simple terms.' } ], ) for block in message.content: if block.type == 'thinking': print('🧠 Thinking:', block.thinking) elif block.type == 'text': print('💬 Response:', block.text) ``` ## Thinking parameters - **`type`**: Set to `'adaptive'` (Claude 4.6 and later) or `'enabled'` (Claude 4.6 and earlier) - **`budget_tokens`**: Maximum number of tokens to allocate for thinking. Only valid with `type: 'enabled'` - **`display`**: With `type: 'adaptive'`, set to `'summarized'` to include thinking text in the response. On Claude Opus 4.7 and later, thinking text is omitted by default ## Response with thinking When thinking is enabled, the response includes thinking blocks: ```json { "id": "msg_123", "type": "message", "role": "assistant", "content": [ { "type": "thinking", "thinking": "Let me think about how to explain quantum entanglement...", "signature": "anthropic-signature-xyz" }, { "type": "text", "text": "Quantum entanglement is like having two magic coins..." } ], "model": "anthropic/claude-opus-5", "stop_reason": "end_turn", "usage": { "input_tokens": 15, "output_tokens": 150 } } ``` ## Next steps - [Reasoning](/docs/ai-gateway/models-and-providers/reasoning) - Per-provider effort levels and model support - [Advanced](/docs/ai-gateway/sdks-and-apis/anthropic-messages-api/advanced) - Web search, provider timeouts, and automatic caching --- [View full sitemap](/docs/sitemap)