Thinking

Thinking-capable models emit a thinking field that separates their reasoning trace from the final answer.

Use this capability to audit model steps, animate the model thinking in a UI, or hide the trace entirely when you only need the final response.

Supported models

• Qwen 3
• GPT-OSS (use think levels: low, medium, high — the trace cannot be fully disabled)
• DeepSeek-v3.1
• DeepSeek R1
• Browse the latest additions under thinking models

Enable thinking in API calls

Set the think field on chat or generate requests. Most models accept booleans (true/false).

GPT-OSS instead expects one of low, medium, or high to tune the trace length.

The message.thinking (chat endpoint) or thinking (generate endpoint) field contains the reasoning trace while message.content / response holds the final answer.

cURL

curl http://localhost:11434/api/chat -d '{
  "model": "qwen3",
  "messages": [{
    "role": "user",
    "content": "How many letter r are in strawberry?"
  }],
  "think": true,
  "stream": false
}'

GPT-OSS requires think to be set to "low", "medium", or "high". Passing true/false is ignored for that model.

Stream the reasoning trace

Thinking streams interleave reasoning tokens before answer tokens. Detect the first thinking chunk to render a “thinking” section, then switch to the final reply once message.content arrives.

Python

from ollama import chat

stream = chat(
  model='qwen3',
  messages=[{'role': 'user', 'content': 'What is 17 × 23?'}],
  think=True,
  stream=True,
)

in_thinking = False

for chunk in stream:
  if chunk.message.thinking and not in_thinking:
    in_thinking = True
    print('Thinking:\n', end='')

  if chunk.message.thinking:
    print(chunk.message.thinking, end='')
  elif chunk.message.content:
    if in_thinking:
      print('\n\nAnswer:\n', end='')
      in_thinking = False
    print(chunk.message.content, end='')

CLI quick reference

• Enable thinking for a single run: ollama run deepseek-r1 --think "Where should I visit in Lisbon?"
• Disable thinking: ollama run deepseek-r1 --think=false "Summarize this article"
• Hide the trace while still using a thinking model: ollama run deepseek-r1 --hidethinking "Is 9.9 bigger or 9.11?"
• Inside interactive sessions, toggle with /set think or /set nothink.
• GPT-OSS only accepts levels: ollama run gpt-oss --think=low "Draft a headline" (replace low with medium or high as needed).

Thinking is enabled by default in the CLI and API for supported models.