.NET: [Feature]: DevUI: Add edit, regenerate, and rerun support for conversation messages

Description

I would like to request improved conversation iteration features in Agent Framework DevUI.

What problem does it solve?

The current DevUI is already very useful for testing and debugging agents locally. However, when iterating on prompts, instructions, tools, or model behavior, it is currently cumbersome to repeat or adjust previous messages.

Typical debugging flow:

1. Send a user message
2. Inspect the agent response, events, traces, and tool calls
3. Notice that the prompt or wording should be changed
4. Manually copy the previous message
5. Create a new conversation or send a modified version again

This makes prompt and agent debugging slower than necessary.

Requested behavior

It would be very useful if DevUI supported one or more of the following features:

• Edit a previous user message and rerun the conversation from that point
• Regenerate the last assistant response
• Rerun the last user message without manually copying it
• Optionally create a new conversation branch when rerunning from an earlier message
• Keep the Events, Traces, and Tools panels connected to the rerun so the new execution can be compared with the previous one

Why would this be useful?

This would make DevUI much more effective as a local development and debugging tool for Agent Framework.

For example, while testing an ASP.NET Core hosted agent with LM Studio or OpenAI-compatible models, developers often need to slightly change a user message or rerun the same prompt after changing:

• agent instructions
• tools
• model settings
• local model
• function descriptions
• system behavior
• tracing / approval flow

Having edit/regenerate/rerun support would make this workflow much faster.

Expected UX

Possible UI options:

• Add a small "Edit" action on user messages
• Add a "Regenerate" action on assistant messages
• Add a "Rerun last message" button near the message composer
• When editing an earlier message, optionally ask whether to:
  • overwrite the current conversation from that point
  • or create a new branch / new conversation

Alternatives considered

The current workaround is to manually copy the previous message and send it again, or to start a new conversation. This works, but it is inconvenient during frequent local agent debugging.

Another alternative is to build a custom AG-UI client, but DevUI is already the most convenient local developer experience for Agent Framework, so having this directly in DevUI would be very valuable.

Code Sample

Language/SDK

.NET

Start by locating the DevUI conversation and message-handling entry points, then review how the Events, Traces, and Tools panels connect to an execution. Define the supported scope among editing, regenerating, rerunning, and branching before implementation. Done should include a clear interaction for the chosen flow and preserve the relevant execution panels for the rerun.