[dotnet-port-fixes] Aggregate loop usage across iterations

[github-actions]

Summary

Align the Go loop harness with the LoopAgent portion of microsoft/agent-framework#7539 so NonStreamingReturnsLastResponseOnly still reports usage from every loop iteration. The loop middleware now accumulates usage across all iterations, removes per-iteration usage from the buffered final response, and reattaches the aggregated usage to the surfaced last response. I also added a regression test that exercises summed token counts and merged AdditionalCounts.

Ported .NET PRs

• .NET: Aggregate usage across looping agents and chat clients agent-framework#7539 - aggregate usage across looping agents and chat clients

Upstream commit referenced: ec32e86646469585bf6d7be83b343c88bf606950 from microsoft/agent-framework. This PR ports only the LoopAgent behavior that maps to agent/harness/loop.

Breaking Changes

No. This corrects internal usage accounting for existing loop runs without changing exported Go API.

Tests and Examples

• Ran go test ./agent/harness/loop
• Added regression coverage in agent/harness/loop/loop_test.go for aggregated usage in last-response-only non-streaming runs
• No example changes were needed for this internal behavior fix

Notes

This intentionally scopes the upstream port to the Go loop harness slice of microsoft/agent-framework#7539. The broader .NET PR also updated other looping components that do not map to this narrow Go change set.

Generated by .NET to Go Fixes and Test Porting Agent · gpt54 · 250.2 AIC · ⌖ 14.4 AIC · ⊞ 24.2K · ◷

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Show patch preview (200 of 200 lines)

From 6812e790368f1f77b68d05b8ddfcc0e54ce36fab Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Mon, 17 Aug 2026 03:00:33 +0000
Subject: [PATCH] [dotnet-port-fixes] Aggregate loop usage across iterations

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 agent/harness/loop/loop.go      | 76 ++++++++++++++++++++++++++++++++-
 agent/harness/loop/loop_test.go | 52 ++++++++++++++++++++++
 2 files changed, 126 insertions(+), 2 deletions(-)

diff --git a/agent/harness/loop/loop.go b/agent/harness/loop/loop.go
index 4b210176a..6624437ab 100644
--- a/agent/harness/loop/loop.go
+++ b/agent/harness/loop/loop.go
@@ -176,6 +176,7 @@ func run(cfg Config, next agent.RunFunc, ctx context.Context, messages []*messag
 		returnLastResponseOnly := cfg.NonStreamingReturnsLastResponseOnly && !stream
 		initialSession, hasSession := agent.GetOption(opts, agent.WithSession)
 		var initialSessionSnapshot []byte
+		var aggregatedUsage message.UsageDetails
 		loopCtx := &Context{
 			InitialMessages:      initialMessages,
 			Options:              slices.Clone(opts),
@@ -197,6 +198,7 @@ func run(cfg Config, next agent.RunFunc, ctx context.Context, messages []*messag
 				if update != nil {
 					resp.Update(update)
 					if returnLastResponseOnly {
+						aggregatedUsage.Add(update.Usage())
 						iterationUpdates = append(iterationUpdates, cloneResponseUpdate(update))
 					}
 				}
@@ -217,7 +219,7 @@ func run(cfg Config, next agent.RunFunc, ctx context.Context, messages []*messag
 
 			if hasPendingApprovalRequests(&resp) || loopCtx.Iteration >= maxIterations {
 				if returnLastResponseOnly {
-					if !yieldResponseUpdates(yield, iterationUpdates) {
+					if !yieldResponseUpdates(yield, responseUpdatesWithAggregatedUsage(iterationUpdates, aggregatedUsage)) {
 						return
 					}
 				}
@@ -231,7 +233,7 @@ func run(cfg Config, next agent.RunFunc, ctx context.Context, messages []*messag
 			}
 			if !ok {
 			
... (truncated)

[michelle-clayton-work]

Pull request #862 is linked to this issue and will close it when merged.