Migration to Responses

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Mental Model Shift

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When To Stay On Messages

• your app already depends on Anthropic SDK behavior
• your tooling expects content blocks directly
• migration cost is higher than the near-term benefit

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When To Migrate

• you want the recommended primary NagaAI LLM surface
• you are starting a new app or redesigning your current one
• you want one docs path for new feature work

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Field mapping

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Simple request conversion

{
  "model": "claude-sonnet-4.5",
  "messages": [
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "Summarize this document."
        }
      ]
    }
  ]
}

{
  "model": "claude-sonnet-4.5",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "Summarize this document."
        }
      ]
    }
  ]
}

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Tool and reasoning notes

• Anthropic tool_use and tool_result blocks map to function_call and function_call_output
• visible thinking maps to reasoning items and Responses reasoning events
• if you preserve reasoning continuity across turns, replay reasoning payloads unchanged

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Next steps

• Responses API
• Responses Streaming
• Responses Tool Calling
• Messages API