I am developing an application using the GWS Chat API and need technical support.
1. Use Case to be Implemented
An employee asks a work-related question to the chatbot via Google Chat 1:1 bot DM.
The person in charge’s name is displayed in the chatbot’s response as a user mention chip.
We want to implement a feature where a profile card (Name/Email/Message buttons) appears when the employee hovers the mouse over the person’s name.
2. Internal Test Results
We inserted the user mention format as follows into the Webhook response body:
{
“text”: “Person in Charge: <users/111803362263611858271>/<users/108671446647545753952>”
}
Result in 1:1 bot DM:
Mentioned user_id / User screen result / Member status
108671446647545753952 / @Chanyoung Park chip + hover card normal 
/ DM Member (Self)
111803362263611858271 / Rendered empty 
/ DM Non-member
-> The user_id format and transmission mechanism are functioning correctly (verified with the self case). However, it has been confirmed that mentions to users who are not DM members are automatically removed.
3. Key Questions
Q1
Please confirm if it is true that USER_MENTION chip rendering for non-member users (other users within the same workspace domain) is officially blocked in a 1:1 bot DM environment.
Q2
If this is indeed a blocked behavior, please confirm if there are any methods among the following to bypass or allow it.
Changes to Admin Console (Admin) policies
Adjusting OAuth scopes
Adding API permissions
Whether to publish to Google Workspace Marketplace
Q3
If the USER_MENTION type is explicitly included in the annotations[] array in a Chat API messages.create call or a webhook response, is non-member chip rendering possible? {
“text”: “Manager: Kim Beom-taek”,
“annotations”: [{
“type”: “USER_MENTION”,
“startIndex”: 5,
“length”: 3,
“userMention”: {
“user”: {“name”: “users/111803362263611858271”, “type”: “HUMAN”},
“type”: “MENTION”
}
}]
}
Q4
If all of the above methods are not possible, is there an officially recommended pattern for displaying non-member manager profile cards in 1:1 bot DMs? (A method to handle this within the 1:1 DM without creating a separate space)
Q5
Do different policies apply to higher-tier plans such as Enterprise or Education? Please confirm if this feature becomes available if our company upgrades to a higher-tier plan.
Additional Notes
If possible, please attach a link to official Google documentation or administrator guides along with your official response.
Differences in compatibility between App Authentication vs. Domain-Wide Delegation authentication methods (if applicable)