Use Agent Identity. The service_account field must not be set.
ServiceAccount
Use a custom service account if the service_account field is set,
otherwise use the default Vertex AI Reasoning Engine Service Agent in the
project.
Unspecified
Default value. Use a custom service account if the service_account
field is set, otherwise use the default Vertex AI Reasoning Engine
Service Agent in the project. Same behavior as SERVICE_ACCOUNT.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2026-07-14 UTC."],[],[]]