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Mastering Codex and the OpenAI Agents SDK in 5 Days

D3 The Responses API and Built-in Tools: Function Calling, Web Search / File Search / Computer Use, Structured Output

• How does the Responses API differ from Chat Completions, and what are the common pitfalls when migrating?Responses API 和 Chat Completions 的区别是什么？从 Chat Completions 迁移过去最容易踩什么坑？

  Common in ChinaCommon overseasBasic#responses-api#openai#migration

  How to reason about it · think before answering

  1. This tests whether you have actually migrated code, not whether you can recite field names.
  2. Split into three axes: input shape (messages array becomes input plus top-level instructions), output shape (choices becomes typed output items with an output_text helper), and state (stateless becomes store by default plus previous_response_id).
  3. Explain the motivation: a chat-transcript model cannot hold tool actions; items give search, function calls and their outputs distinct types, which is what makes built-in tools possible.
  4. Name three pitfalls: store defaults to true so compliance-sensitive apps must disable it; output is an array, so read output_text or walk message items; tool results move from role tool messages to function_call_output items keyed by call_id.
  5. Expect the follow-up: previous_response_id versus self-managed history? Prototypes take the former; production usually keeps its own history for audit and recovery, or mixes both.

  分析过程 · 先想清楚再作答

  1. 这题考的是你有没有真迁移过，而不是能不能背出字段名。只答「新接口更强」会被判为看过文档没写过代码。
  2. 拆成三个维度：输入形态（messages 数组变成 input 加顶层 instructions）、输出形态（choices 变成按类型排列的 output items，SDK 给 output_text 助手）、状态管理（无状态变成默认 store 加 previous_response_id）。
  3. 再说为什么要改：聊天记录模型装不下工具动作；items 让搜索、函数调用、回填各有自己的类型，这是内置工具能接进来的前提。
  4. 迁移坑给三条：默认 store 为 true 意味着数据会被存下来，合规场景要显式关掉；output 是数组不是单个消息，取文本要用 output_text 或遍历 message item；函数调用的回填从 role 为 tool 的消息变成 function_call_output item，call_id 要对上。
  5. 可预期的追问：previous_response_id 和自己维护历史怎么选？原型用前者省事，生产多半自己落一份历史做审计与恢复，或两者混用。

  Key points

  • Input: messages become input plus top-level instructions; output: choices become typed output items plus output_text
  • State: store defaults to true and previous_response_id chains turns without resending history
  • The motivation is distinct item types for tool actions, enabling built-in tools
  • Pitfalls: store on by default, output is an array, tool results go back as function_call_output keyed by call_id

  答题要点

  • 输入：messages 变 input 加顶层 instructions；输出：choices 变按类型排列的 output items 与 output_text
  • 状态：默认 store 为 true，用 previous_response_id 接上一轮，不再每轮重发历史
  • 改的动机是给工具动作独立的 item 类型，内置工具由此接入
  • 迁移坑：store 默认开、output 是数组、回填要用 function_call_output 且 call_id 对上