AutoGen Studio is **broken** due to a missing message class (LLMCallEventMessage) (v0.5+)

[SongChiYoung]

What happened?

Describe the bug
AutoGen Studio currently fails to run any agent that emits LLMCallEventMessage, because that class is abstract and not implemented.

This causes the following runtime error:
TypeError: Can’t instantiate abstract class LLMCallEventMessage with abstract methods to_model_message, to_model_text, to_text

This was reported by a user on Discord:

சravanaன் — 6:40 PM
“i updated agentchat and agentcore and tried running the config from agentstudio and it is now not running the agent and is throwing error ...”

To Reproduce
Steps:

1. Use AgentStudio (v0.4.x from PyPI or v0.5.x from Githun repo too)
2. Add an agent that emits LLMCallEventMessage - Any agent
3. Run
   → Error will occur immediately, breaking the execution.

Expected behavior
Agent should run without error. LLMCallEventMessage is meant for logging, not model input, so it should be safely handled.

Fix
Fix is proposed in PR: #6204
This defines the class with to_model_message() marked as NotImplementedError.

Additional context

• This issue blocks AgentStudio for many use cases using latest AgentCore.
• Quick merge & release would help users avoid this broken state.

Screen shot

Which packages was the bug in?

AutoGen Studio (autogensudio)

AutoGen library version.

Python dev (main branch)

Other library version.

No response

Model used

No response

Model provider

None

Other model provider

No response

Python version

None

.NET version

None

Operating system

None