Assistants

OpenAI has shut down the Assistants API

OpenAI deprecated the Assistants API on August 26, 2025 and removed it on August 26, 2026 (see OpenAI's deprecations page). Requests from the assistants endpoint to OpenAI no longer succeed. Use Agents instead: they work with OpenAI models and provide the same capabilities (code execution, file search, actions, and tools) without depending on the Assistants API.

The rest of this page is kept for reference.

The Assistants API by OpenAI has a dedicated endpoint.
The Assistants API enables the creation of AI assistants, offering functionalities like code interpreter, knowledge retrieval of files, and function execution.
- Read here for an in-depth documentation of the feature, how it works, what it's capable of.
As with the regular OpenAI API, go to https://platform.openai.com/account/api-keys to get a key.
You will need to set the following environment variable to your key or you can set it to user_provided for users to provide their own.

ASSISTANTS_API_KEY=your-key

You can determine which models you would like to have available with ASSISTANTS_MODELS; otherwise, the models list fetched from OpenAI will be used (only Assistants API compatible models will be shown).

ASSISTANTS_MODELS=gpt-3.5-turbo-0125,gpt-3.5-turbo-16k-0613,gpt-3.5-turbo-16k,gpt-3.5-turbo,gpt-4,gpt-4-0314,gpt-4-32k-0314,gpt-4-0613,gpt-3.5-turbo-0613,gpt-3.5-turbo-1106,gpt-4-0125-preview,gpt-4-turbo-preview,gpt-4-1106-preview

If necessary, you can also set an alternate base URL instead of the official one with ASSISTANTS_BASE_URL, which is similar to the OpenAI counterpart OPENAI_REVERSE_PROXY

ASSISTANTS_BASE_URL=http://your-alt-baseURL:3080/

There is additional, optional configuration, depending on your needs, such as disabling the assistant builder UI, that are available via the librechat.yaml custom config file:
- Control the visibility and use of the builder interface for assistants. More info
- Specify the polling interval in milliseconds for checking run updates or changes in assistant run states. More info
- Set the timeout period in milliseconds for assistant runs. Helps manage system load by limiting total run operation time. More info
- Specify which assistant Ids are supported or excluded More info

Strict function calling

With librechat you can add add the 'x-strict': true flag at operation-level in the openapi spec for actions. This will automatically generate function calls with 'strict' mode enabled. Note that strict mode supports only a partial subset of json. Read https://platform.openai.com/docs/guides/structured-outputs for details.

For example:

{
  "openapi": "3.1.0",
  "info": {
    "title": "Math.js API",
    "description": "API for performing mathematical operations, such as addition, subtraction, etc.",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "https://api.mathjs.org/v4"
    }
  ],
  "paths": {
    "/": {
      "post": {
        "summary": "Evaluate a mathematical expression",
        "description": "Sends a mathematical expression in the request body to evaluate.",
"operationId": "math",
        "x-strict": true,
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "type": "object",
                "properties": {
                  "expr": {
                    "type": "string",
                    "description": "The mathematical expression to evaluate (e.g., `2+3`)."
                  }
                },
                "required": ["expr"]
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "The result of the evaluated expression.",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "result": {
                      "type": "number",
                      "description": "The evaluated result of the expression."
                    }
                  }
                }
              }
            }
          },
          "400": {
            "description": "Invalid expression provided.",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "error": {
                      "type": "string",
                      "description": "Error message describing the invalid expression."
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

Notes

Notes:

At the time of writing, only the following models support the Retrieval capability:
- gpt-3.5-turbo-0125
- gpt-4-0125-preview
- gpt-4-turbo-preview
- gpt-4-1106-preview
- gpt-3.5-turbo-1106
Vision capability is not yet supported.
If you have previously set the ENDPOINTS value in your .env file, you will need to add the value assistants

Assistants

Strict function calling

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