Responses API, built-in tools and Agents SDK
The Responses API, built-in web search, file search and computer-use tools, and the open-source Agents SDK become OpenAI's agent-building stack.
Responses combines Chat Completions simplicity with Assistants-style tool use and becomes the primary API; Assistants API sunset was announced (shut down 2026-08-26). Computer-use tool exposes the CUA model at $3/$12 per million tokens. Agents SDK replaces the Swarm demo with handoffs and guardrails.
- Date
- Tuesday, 11 March 2025
- Lab
- OpenAI
- Kind
- product
- Access
- closed API
- Price
- See numbers
Figures
| Measure | Value | Measured by |
|---|---|---|
| Web search tool, SimpleQA (gpt-4o-search-preview) | 90% gpt-4o-mini-search-preview 88% | company |
| Computer-use tool price (input / output per 1M tokens) | $3 / $12 research preview, usage tiers 3-5 | company |
| File search price | $2.50 per 1,000 queries plus $0.10/GB/day storage | company |
OpenAI added support for Anthropic's Model Context Protocol to the Agents SDK on 2025-03-26 (OpenAIDevs post, quoted by Simon Willison) and remote MCP servers to the Responses API on 2025-05-20 (changelog).
Sources
- openai.com/index/new-tools-for-building-agents/
- simonwillison.net/2025/Mar/11/openai-agents-sdk/
- developers.openai.com/api/docs/changelog
This record was checked against its sources on 6 October 2026. How we check