gh-jezweb-claude-skills-skills-openai-responses/references/reasoning-preservation.md

Reasoning Preservation Guide

Last Updated: 2025-10-25

Understanding how Responses API preserves reasoning across turns.

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What Is Reasoning Preservation?

Unlike Chat Completions (which discards reasoning between turns), Responses preserves the model's internal thought process.

Analogy:

• Chat Completions: Model tears out scratchpad page after each turn
• Responses API: Model keeps scratchpad open, previous reasoning visible

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Performance Impact

TAUBench Results (GPT-5):

• Chat Completions: Baseline
• Responses API: +5% better (purely from preserved reasoning)

Why It Matters:

• ✅ Better multi-turn problem solving
• ✅ More coherent long conversations
• ✅ Improved step-by-step reasoning
• ✅ Fewer context errors

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Reasoning Summaries

Responses API provides reasoning summaries at no additional cost.

const response = await openai.responses.create({
  model: 'gpt-5',
  input: 'Solve this complex math problem',
});

// Inspect reasoning
response.output.forEach(item => {
  if (item.type === 'reasoning') {
    console.log('Model thinking:', item.summary[0].text);
  }
  if (item.type === 'message') {
    console.log('Final answer:', item.content[0].text);
  }
});

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Use Cases

Debugging:

• See how model arrived at answer
• Identify reasoning errors

Auditing:

• Track decision-making process
• Compliance requirements

Transparency:

• Show users why AI made decision
• Build trust in AI systems

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Official Docs: https://developers.openai.com/blog/responses-api/