What's new in Assistants API

Beta

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Discover new features and improvements in Assistants API.

March 2025

Based on developer feedback from the Assistants API beta, we've incorporated key improvements into the Responses API, making it more flexible, faster, and easier to use.

• We launched the Responses API, a new API primitive with built-in tools, like function calling, file search, web search, and computer use.
• We're working to achieve full feature parity between the Assistants and the Responses API, including support for Assistant-like and Thread-like objects and the Code Interpreter tool. We will communicate updates to the Assistants API in the changelog.
• After achieving full feature parity, we plan to formally announce the deprecation of the Assistants API with a target sunset date in the first half of 2026. Upon deprecation, we will provide a clear migration guide from the Assistants API to the Responses API that allows developers to preserve all their data and migrate their applications.
• Until we formally announce the deprecation, we will continue delivering new models to the Assistants API. The Responses API represents the future direction for building agents on OpenAI.

April 2024

We are announcing a variety of new features and improvements to the Assistants API and moving our Beta to a new API version, OpenAI-Beta: assistants=v2. Here's what's new:

• We're launching an improved retrieval tool called file_search, which can ingest up to 10,000 files per assistant - 500x more than before. It is faster, supports parallel queries through multi-threaded searches, and features enhanced reranking and query rewriting.
• Alongside file_search, we're introducing vector_store objects in the API. Once a file is added to a vector store, it's automatically parsed, chunked, and embedded, made ready to be searched. Vector stores can be used across assistants and threads, simplifying file management and billing.
• You can now control the maximum number of tokens a run uses in the Assistants API, allowing you to manage token usage costs. You can also set limits on the number of previous / recent messages used in each run.
• We've added support for the tool_choice parameter which can be used to force the use of a specific tool (like file_search, code_interpreter, or a function) in a particular run.
• You can now create messages with the role assistant to create custom conversation histories in Threads.
• Assistant and Run objects now support popular model configuration parameters like temperature, response_format (JSON mode), and top_p.
• You can now use fine-tuned models in the Assistants API. At the moment, only fine-tuned versions of gpt-3.5-turbo-0125 are supported.
• Assistants API now supports streaming.
• We've added several streaming and polling helpers to our Node and Python SDKs.

See our migration guide to learn more about how to migrate your tool usage to the latest version of the Assistants API.