Reasoning

Reasoning models think before they answer. You choose how hard with reasoning_effort, can read the thinking in reasoning_content, and pay for it as output tokens.

reasoning_effort

Send reasoning_effort with one of none, minimal, low, medium, high, xhigh or max. Any other value is a 400. Each provider supports its own subset, mapped as below; a value the model can’t honour returns 400 with the code validation_reasoning_effort_unsupported.

How each provider takes reasoning_effort
Modelsreasoning_effort
GPT-6 Astra, GPT-6.1 Sol, GPT-6.1 TerraPassed to OpenAI. minimal becomes low; on GPT-6 Astra and GPT-6.1 Sol, none also becomes low.
DeepSeek V4.1 Flashnone (thinking off), low, high, max. medium, minimal and xhigh are refused.
Kimi K3.1 Pro, Kimi K3.1 Pro HighspeedAlways thinks. none, minimal and low run at low; medium and high at high; xhigh and max at max. Sampling settings such as temperature are fixed by the model and ignored.

curl

curl https://api.airuntime.dev/v1/chat/completions \
  -H "Authorization: Bearer $TOKENS_PAY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-6-astra",
    "reasoning_effort": "high",
    "messages": [{"role": "user", "content": "Is 1,000,003 prime?"}]
  }'

reasoning_content

When the model returns its thinking, it is in choices[0].message.reasoning_content, or choices[0].delta.reasoning_content when streaming. The answer stays in content. You can send an assistant message’s reasoning_content back in the next request.

reasoning_tokens and billing

usage.completion_tokens_details.reasoning_tokens reports how many output tokens were thinking, when the provider reports it. It is already counted in completion_tokens: thinking is billed as output, at the model’s output rate. Higher effort usually means more output tokens.

Reasoning models

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