User-delegated authentication from a Custom Widget to an external system

Hi,
I’m investigating how to preserve individual user identity when a Foundry Custom Widget triggers operations in an external system.

Users authenticate to Foundry through enterprise SSO. The external system has its own OIDC-compatible identity and permission model, and every write must be attributed to the actual user rather than a shared service account.

What is the recommended supported pattern for this?

  • Is there an on-behalf-of or token-exchange flow between Foundry and an external identity provider?
  • Can an Action or webhook receive a cryptographically verifiable identity for the Foundry user who invoked it?
  • Can a Custom Widget access any user-delegated token intended for an external audience, or is its runtime token strictly for Foundry APIs?

I want to avoid passing an unverified user identifier in the request body or treating a service credential as an individual user.

Yes, this exists and is called Outbound Applications:

https://www.palantir.com/docs/foundry/administration/configure-outbound-applications#configure-outbound-applications-with-oauth-20-authorization-code-grants

However, I am not sure this is supported from Custom Widgets or deployed React apps.