> ## Documentation Index
> Fetch the complete documentation index at: https://plain-docs-orca-916-agent-docs-restructure.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# createThreadFieldSchema

> Creates a new thread field schema, defining a custom field that can be attached to threads. The `key` must be unique within the workspace and cannot be changed after creation. Requires the `threadFieldSchema:create` permission.