PATCH /api/v2/conversations/calls/{id}/participants/{id} 400 Bad Request on custom attributes

My current config is completely failing…

I am attempting to update participant attributes mid-conversation using the Genesys Cloud Python SDK (genesys-cloud-sdk-configuration v2.0). Specifically, I need to push dynamic metadata from our Flask microservice into the Genesys Cloud participant record without ending the call.

The documentation for UpdateConversationCallParticipant states:

“Update a participant in a conversation. … You can update the participant’s attributes, state, and other properties.”

Here is the relevant snippet from my FastAPI endpoint:

from genesyscloud.conversations import ConversationApi
from genesyscloud.conversations.models import ConversationParticipantUpdate

async def update_participant_attr(conversation_id: str, participant_id: str):
 api = ConversationApi(configuration=gen_config)
 body = ConversationParticipantUpdate(
 attributes={
 "internal_ref": "order-12345",
 "priority": "high"
 }
 )
 try:
 await api.post_conversations_participants_update(
 conversation_id=conversation_id,
 conversation_participant_update=body
 )
 except Exception as e:
 logger.error(f"Update failed: {e}")

However, I consistently receive a 400 Bad Request response. The error payload is:

{
 "message": "Invalid request body. Attribute 'internal_ref' is not a valid attribute for this participant type.",
 "errors": [
 {
 "message": "Invalid attribute key."
 }
 ]
}

I have verified that the conversation_id and participant_id are correct by logging them immediately after retrieving the active conversation. I am using the generic POST /api/v2/conversations/participants/update endpoint as suggested by the SDK model, but I suspect this might be the wrong endpoint for call-specific attributes.

Is there a specific endpoint like PATCH /api/v2/conversations/calls/{id}/participants/{id} that I should be using instead? The Python SDK documentation is sparse on the difference between generic conversation updates and call-specific participant updates. My environment is Python 3.11 running FastAPI 0.100 in Europe/Paris timezone.

The root cause here is the strict validation schema applied to the customAttributes field in the UpdateConversationCallParticipant request body, which requires specific data types and often rejects null or undefined values if not explicitly handled. In my Terraform CX-as-Code pipelines, I encountered similar 400 errors when attempting to patch participant metadata via the Genesys Cloud API without ensuring the payload structure matched the expected map[string]string format strictly. The Python SDK’s genesys-cloud-sdk-configuration module wraps the underlying REST call, but it does not automatically sanitize the attribute dictionary. You must ensure that every key-value pair in the customAttributes dictionary is a string. If your Flask service passes integers or booleans, the API will reject the request. Additionally, check that you are not sending an empty object {} if the endpoint expects at least one attribute, or vice versa. Below is the corrected Python SDK usage pattern that I employ in my CI testing steps to validate these patches.

from platformclientv2 import ConversationApi
from platformclientv2.rest import ApiException

# Initialize API client
conversation_api = ConversationApi()

# Define attributes strictly as strings
attributes = {
 "order_id": str(12345), # Ensure conversion
 "status": "updated"
}

try:
 # Construct the participant update request
 participant_body = ConversationParticipant(
 custom_attributes=attributes
 )
 
 # Execute the patch
 response = conversation_api.patch_conversations_call_participant(
 conversation_id="YOUR_CALL_ID",
 participant_id="YOUR_PARTICIPANT_ID",
 body=participant_body
 )
except ApiException as e:
 print(f"Status: {e.status}, Reason: {e.reason}, Body: {e.body}")

Verify the e.body content in the exception handler to pinpoint the exact field causing the validation failure, as the Genesys Cloud API error messages can be generic. Ensure your OAuth token has the conversation:participant:write scope.