vercel.onProjectEnvironmentVariableEvent covers creation, update, and deletion. Use a specific trigger for one operation.
automations/audit-vercel-environment-variables.automation.ts
account defaults to the project’s Vercel binding and must use OAuth.
Trigger data
The eventtype is project.env-variable.created, project.env-variable.updated, or project.env-variable.deleted. Vercel sends project and variable IDs, the owning team or user, and metadata, but never the variable value.