[dotnet-port] Preserve AGUI session history across multi-turn runs

[Quim Muntal (qmuntal)]

The AG-UI provider assigns a thread ID to the session on the first run by calling session.SetServiceID(threadID). The agent's history machinery interpreted any non-empty ServiceID as a signal that the service manages history server-side, and therefore disabled the local HistoryProvider for every subsequent run. This caused conversation history to be dropped after the first turn.

Add ServiceDoesNotManageHistory bool to ProviderConfig. Providers that never delegate history to the service (e.g. AGUI) set this flag true; the agent then preserves the HistoryProvider across runs regardless of whether the session has a ServiceID. This also prevents the provider from being flagged as a conflict when a user-configured HistoryProvider is present.

Set ServiceDoesNotManageHistory: true in the AGUI provider constructor.

Add TestAGUIAgentRun_WithSession_PreservesHistoryAcrossMultipleTurns to verify that the second run sends the full conversation history (3 messages) rather than only the new user message.

Ports behavior fix from microsoft/agent-framework#5904.

[Copilot]

Pull request overview

This PR fixes AG-UI multi-turn sessions dropping conversation history after the first run. The root cause was that the agent treated any non-empty Session.ServiceID as “service-managed history,” which disabled the local HistoryProvider for subsequent turns; AG-UI sets a thread ID into ServiceID but still requires the client to send full history every run.

Changes:

• Add ServiceDoesNotManageHistory to agent.ProviderConfig and thread it into the agent’s history selection / conflict logic.
• Set ServiceDoesNotManageHistory: true for the AG-UI provider so local history is preserved even when Session.ServiceID is set.
• Add an AG-UI test ensuring the second run includes full history (3 messages) rather than only the new user message.

Show a summary per file

File	Description
agent/provider/aguiagent/agui.go	Marks AG-UI as not service-managing history so the agent keeps local history across turns despite ServiceID usage.
agent/provider/aguiagent/agui_test.go	Adds coverage to ensure multi-turn runs with the same session include full prior conversation history.
agent/agent.go	Introduces provider-level override (ServiceDoesNotManageHistory) and applies it to history-provider selection, storage, and conflict handling.

Copilot's findings

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• Files reviewed: 3/3 changed files
• Comments generated: 0

[github-actions]

Cross-repo parity review — PR #258

Behavioral parity: ✅ aligned

The upstream fix in microsoft/agent-framework#5904 and this Go port address exactly the same bug: the AGUI provider assigns a thread ID (ServiceID) to the session on the first run, which was previously misread as "service manages history server-side," causing local history to be dropped on subsequent turns. Both ports fix this and add an equivalent two-turn regression test.

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API approach divergence — worth noting

The .NET and Go fixes solve the problem through different extension mechanisms:

	.NET (PR #5904)	Go (this PR)
Mechanism	Private constant AGUIProviderName = "ag-ui" + private IsAGUIProviderName() helper inside ChatClientAgent.cs	New public exported field ServiceDoesNotManageHistory bool on ProviderConfig
Scope	Hardcoded per provider name, entirely internal	Generic opt-in flag, set by any provider implementation
Public API change	None	Yes — new exported field on ProviderConfig

The Go approach is more extensible: any provider that never delegates history to the service can set the flag rather than requiring the core agent to grow a new hardcoded provider-name check for each such provider. However, this introduces a new public exported field (ProviderConfig.ServiceDoesNotManageHistory) that has no direct counterpart in the .NET public surface.

This divergence is intentional and Go-idiomatic — providers in Go are constructed via ProviderConfig rather than via a named string matched inside a monolithic agent type. The semantic contract is the same; only the extension point differs. If .NET later adds more providers with the same "caller supplies full history" behavior, they may want to revisit the hardcoded IsAGUIProviderName approach in favor of something analogous to this Go flag.

Python: No Python AGUI provider was found in python/packages/; this fix is .NET/Go-specific.

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No blocking parity issues. The behavioral fix is faithfully ported; the API shape difference is justified by the Go architecture and the flag name is self-documenting.

Generated by Go API Consistency Review Agent for issue #258 · ● 2.4M · ◷