Does Magentic orchestration support multi-turn conversation via AG-UI? If not, is this planned?

[Kevinjvn]

Summary

We are trying to build a multi-turn chat experience using the Magentic orchestration pattern exposed through an AG-UI endpoint. After testing and investigation, it appears that Magentic does not support multi-turn conversation in the same way that Handoff does, and we want to confirm whether this is by design or a gap.

Environment

• agent-framework-core 1.x (Python)
• agent-framework-ag-ui
• agent-framework-orchestrations
• Foundry project endpoint

What we observe

With Handoff workflow — works correctly

After each agent turn, RUN_FINISHED contains an interrupt array:

{
  "type": "RUN_FINISHED",
  "threadId": "...",
  "runId": "...",
  "interrupt": [{
    "id": "366a9397-...",
    "value": { "agent_response": { ... } }
  }]
}

The next user turn is sent as a resume payload referencing that interrupt ID, and the workflow continues correctly.

With Magentic workflow — fails on second turn

RUN_FINISHED emits no interrupt array. Sending a second user message (with a new run_id, same thread_id) immediately fails with:

RuntimeError: This Magentic workflow has already been completed.
No further messages can be processed.
Use the builder to create a new workflow instance to handle additional tasks.

Root cause hypothesis

The Handoff pattern's multi-turn support is powered by HandoffAgentUserRequest: when an agent completes its turn without requesting a handoff, the workflow pauses, emits an interrupt, and waits for the next user message. Magentic has no equivalent mechanism — it is designed around single-task completion and marks itself done after one full execution cycle.

This means:

1. The checkpoint storage passed to MagenticBuilder does not function as a conversational memory store across turns — it only serves plan review and mid-run resume (e.g. enable_plan_review=True).
2. There is no native way to continue a completed Magentic run with a new user message via AG-UI without rebuilding the workflow instance and manually injecting conversation history.

Questions for the team

1. Is multi-turn conversational chat an unsupported use case for Magentic + AG-UI? Or is there a resume/interrupt mechanism for Magentic that is not documented?
2. Does checkpoint_storage in MagenticBuilder serve any purpose beyond plan review and mid-run recovery? Does it persist agent thread history across completed runs?
3. Is support for multi-turn Magentic conversations planned? If so, is there a tracking issue or roadmap item?
4. Is the correct guidance to use Handoff for interactive multi-turn chat and reserve Magentic for single-shot complex tasks?

Why this matters

Magentic is the only orchestration pattern that handles mixed-intent questions well (e.g. "Deploy my React app to App Service — I'm getting this container startup error", which spans both Azure product knowledge and coding). Handoff's routing model forces a question into a single agent's domain, causing loops on mixed-intent input.

A pattern that can handle both multi-turn chat and mixed-intent delegation would be ideal. Right now these two requirements appear to require different patterns with no single solution.

Related

• .NET: Python: [Bug]: Multi-turn tool calls fail with both Responses API and Chat Completions API when used via agent-framework-ag-ui (Foundry project endpoint) #5941 — multi-turn tool calls fail via AG-UI (Python, Foundry endpoint)
• Python: [AG-UI] Error occurs when using with_plan_review in Magentic workflow #3331 — with_plan_review in Magentic + AG-UI errors