4 Nov 2026
Feature
Checks on every tool call
Checks can now run before a tool is called, not only on the final answer.
What changed
Until now, checks ran once, on the agent’s final answer. From today you can attach a check to any tool, and Relay runs it before the call goes out. A refund that is larger than the duplicate charge is stopped before it reaches your payments API.
How to use it
Add a check to the tool definition with checks: […]. Checks written in plain words and checks written in code both work. Failed checks show in the run log in red, with the input that failed.
Sample entry: replace it with your own release notes.
