[dotnet-port-api] Bound tool-approval auto-approval loop

[github-actions]

Summary

Port the recent .NET tool-approval safety cap into Go by adding toolapproval.DefaultMaxAutoApprovalIterations and toolapproval.Config.MaxAutoApprovalIterations, then bounding the middleware's auto-approved reentry loop. When the cap is reached, the middleware now takes one final inner turn without auto-approving again so the caller sees the remaining approval request(s) instead of an unbounded chain of fresh model calls.

This change was selected from upstream commit 74a144085a5fd05921b473001528f3ae0725b76a because it is a small exported-API parity update with targeted regression coverage. The PR also updates the feature-comparison document to reflect the new bounded auto-approval reentry support.

Ported .NET PRs

• .NET: [Bug]: Sample can make endless "loop" resulting in Millions on tokens spent if you do not terminate process yourself :-( agent-framework#7472 - Bound the tool-approval auto-approval loop

Breaking Changes

No. Existing auto-approval behavior is preserved until the new safety cap is reached; after that point the middleware now surfaces the remaining approval request(s) to the caller instead of continuing an unbounded reentry loop.

Tests and Examples

• go test ./agent/harness/toolapproval
• Added regression tests for capped auto-approval reinvocation, final-turn passthrough of raw approval requests, and negative config validation.
• No example changes were needed because the upstream .NET port did not require sample updates.

Notes

• Duplicate check: no matching existing [dotnet-port-api] or [dotnet-port-fixes] port for this cap was found in recent Go tracking PRs/issues; related tool-approval PRs (Add tool approval middleware for HITL parity #138, [dotnet-port] Port auto-approval rules (heuristics) to toolapproval middleware #254, [dotnet-port] Port auto-approve non-approval-required tools in mixed batches #256, [dotnet-port-fixes] Gate approval-required Copilot tools #459) cover different behavior.
• Skipped recent upstream candidates such as .NET: [Experimental] Extend A2A task store with isolation key scoping agent-framework#7504 (A2A task-store isolation scoping) because they are materially broader hosting/storage ports, and #7262 because it was sample-only and Go already has the exported harness APIs.

Generated by .NET to Go API Porting Agent · gpt54 · 366.5 AIC · ⌖ 13.4 AIC · ⊞ 24.1K · ◷

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Show patch preview (258 of 258 lines)

From b0b90f4b1f85a8a87f5d83e78349f24ace52263d Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Fri, 7 Aug 2026 06:08:58 +0000
Subject: [PATCH] [dotnet-port-api] Bound tool-approval auto-approval loop

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 agent/harness/toolapproval/toolapproval.go    |  48 +++++++-
 .../harness/toolapproval/toolapproval_test.go | 113 ++++++++++++++++++
 docs/dotnet-go-sdk-feature-comparison.md      |   2 +-
 3 files changed, 160 insertions(+), 3 deletions(-)

diff --git a/agent/harness/toolapproval/toolapproval.go b/agent/harness/toolapproval/toolapproval.go
index d07482b69..4d53ac836 100644
--- a/agent/harness/toolapproval/toolapproval.go
+++ b/agent/harness/toolapproval/toolapproval.go
@@ -26,7 +26,14 @@ import (
 	"github.com/microsoft/agent-framework-go/tool"
 )
 
-const stateKey = "toolApprovalState"
+const (
+	stateKey = "toolApprovalState"
+
+	// DefaultMaxAutoApprovalIterations is the default safety cap for how many
+	// times a single run may re-invoke the wrapped agent because every surfaced
+	// approval request was auto-approved.
+	DefaultMaxAutoApprovalIterations = 40
+)
 
 // Rule is a standing approval rule. If Arguments is nil, all invocations of
 // the named tool are auto-approved. Otherwise only invocations with an exact
@@ -79,6 +86,7 @@ func saveState(opts []agent.Option, s state) {
 // New creates a tool-approval middleware that wraps agent runs with
 // human-in-the-loop approval management.
 func New(cfg Config) agent.Middleware {
+	cfg.MaxAutoApprovalIterations = normalizeMaxAutoApprovalIterations(cfg.MaxAutoApprovalIterations)
 	return agent.MiddlewareFunc(func(next agent.RunFunc, ctx context.Context, messages []*message.Message, opts ...agent.Option) iter.Seq2[*agent.ResponseUpdate, error] {
 		return run(cfg, next, ctx, messages, opts...)
 	})
@@ -94,6 +102,14 @@ type Config struct {
 	// to be auto-approved without prompting the 
... (truncated)