AX Agent 구조를 claw-code 기준으로 추가 정리해 transcript 렌더와 tool streaming 책임을 분리함

- ChatWindow.TranscriptRendering partial을 추가해 transcript windowing, 증분 렌더, 스크롤 보존 로직을 메인 ChatWindow.xaml.cs에서 분리
- StreamingToolExecutionCoordinator를 도입해 read-only 도구 prefetch, tool-use 스트리밍 수신, context overflow/transient error 복구를 별도 계층으로 이동
- AgentLoopRuntimeThresholds helper를 추가해 no-tool, plan retry, terminal evidence gate 임계값 계산을 AgentLoopService에서 분리
- AgentLoopTransitions.Execution은 coordinator thin wrapper 중심 구조로 정리해 이후 executor 고도화와 정책 변경이 덜 위험하도록 개선
- README와 docs/DEVELOPMENT.md를 2026-04-09 09:14 (KST) 기준으로 갱신
- 검증: dotnet build src/AxCopilot/AxCopilot.csproj -c Release -v minimal -p:OutputPath=bin\\verify\\ -p:IntermediateOutputPath=obj\\verify\\ (경고 0, 오류 0)

README.md

@@ -1521,3 +1521,9 @@ MIT License
   - [ChatWindow.TranscriptHost.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.TranscriptHost.cs)를 추가해 transcript 요소 추가/교체/삭제와 스크롤 접근을 공용 helper로 정리했고, 내부 ScrollViewer도 한 번만 찾아 재사용하도록 바꿨습니다.
   - [ChatWindow.xaml](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.xaml)의 메시지 영역은 `VirtualizingStackPanel`을 쓰는 `ListBox` 기반 호스트로 교체해, 이후 `claw-code`의 `VirtualMessageList`에 더 가까운 가상화 구조로 밀어갈 수 있는 기반을 만들었습니다.
   - 관련 렌더 코드([ChatWindow.xaml.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.xaml.cs), [ChatWindow.MessageBubblePresentation.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.MessageBubblePresentation.cs), [ChatWindow.AgentEventRendering.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.AgentEventRendering.cs), [ChatWindow.MessageInteractions.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.MessageInteractions.cs), [ChatWindow.TimelinePresentation.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.TimelinePresentation.cs))도 모두 컬렉션 기반 조작으로 맞춰, 실행 중 `Children` 직접 조작에 따른 레이아웃 churn을 줄였습니다.
+- 업데이트: 2026-04-09 09:14 (KST)
+  - `claw-code`와의 구조 대조 결과를 바탕으로, transcript 렌더와 tool streaming 실행 책임을 더 분리했습니다.
+  - [ChatWindow.TranscriptRendering.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.TranscriptRendering.cs)를 추가해 `RenderMessages()`와 transcript windowing/증분 렌더 흐름을 메인 [ChatWindow.xaml.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.xaml.cs) 밖으로 옮겼습니다.
+  - [StreamingToolExecutionCoordinator.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Services/Agent/StreamingToolExecutionCoordinator.cs)를 추가해 read-only 도구 prefetch, tool-use 스트리밍 수신, context overflow/transient error 복구를 별도 coordinator 계층으로 분리했습니다.
+  - [AgentLoopRuntimeThresholds.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Services/Agent/AgentLoopRuntimeThresholds.cs)를 추가해 no-tool, plan retry, terminal evidence gate 같은 임계값 계산을 `AgentLoopService`에서 분리했습니다.
+  - 결과적으로 Cowork/Code의 핵심 루프는 정책 소비자에 더 가까워졌고, 이후 transcript 진짜 가상화와 모델별 실행 정책 조정도 덜 위험하게 진행할 수 있는 구조가 됐습니다.

docs/DEVELOPMENT.md

@@ -5503,3 +5503,20 @@ ow + toggle ?쒓컖 ?몄뼱濡??ㅼ떆 ?뺣젹?덈떎.
   - 실행 중 `Children.Add/Remove`에 직접 매달리던 경로를 줄여 레이아웃 churn을 완화했다.
   - `claw-code`의 `VirtualMessageList`처럼 완전한 전면 가상화는 아니지만, 그 단계로 가기 위한 transcript host 분리를 마쳤다.
   - 이후 단계에서는 이 컬렉션 호스트 위에 실제 item virtualization/placeholder/windowing을 더 강하게 적용할 수 있다.
+
+## 2026-04-09 09:14 (KST)
+
+- `claw-code` 구조 대조 재점검
+  - [Messages.tsx](/E:/AX%20Copilot%20-%20Codex/claw-code/claw-code-f5a40b86dede580f6543bf8926c9af017eea9409/src/components/Messages.tsx), [VirtualMessageList.tsx](/E:/AX%20Copilot%20-%20Codex/claw-code/claw-code-f5a40b86dede580f6543bf8926c9af017eea9409/src/components/VirtualMessageList.tsx), [StreamingToolExecutor.ts](/E:/AX%20Copilot%20-%20Codex/claw-code/claw-code-f5a40b86dede580f6543bf8926c9af017eea9409/src/services/tools/StreamingToolExecutor.ts)를 다시 대조한 결과, AX는 메인 창과 AgentLoop에 아직 일부 오케스트레이션 책임이 과밀한 상태였다.
+- [ChatWindow.TranscriptRendering.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.TranscriptRendering.cs)
+  - transcript windowing, 증분 렌더, scroll preserve를 전담하는 partial을 새로 추가했다.
+  - 메인 [ChatWindow.xaml.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Views/ChatWindow.xaml.cs) 에서 `RenderMessages()`와 관련 스크롤 처리 로직을 분리해, transcript 구조 개선을 독립적으로 이어갈 수 있게 정리했다.
+- [StreamingToolExecutionCoordinator.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Services/Agent/StreamingToolExecutionCoordinator.cs)
+  - read-only 도구 prefetch, tool-use 스트리밍 수신, partial tool-call 수집, context overflow/transient error 복구 루프를 별도 coordinator로 이동했다.
+  - [AgentLoopTransitions.Execution.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Services/Agent/AgentLoopTransitions.Execution.cs)는 이제 thin wrapper로 coordinator를 호출하는 구조가 되어, 이후 `claw-code`식 executor 고도화를 더 쉽게 적용할 수 있다.
+- [AgentLoopRuntimeThresholds.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Services/Agent/AgentLoopRuntimeThresholds.cs)
+  - no-tool response threshold, no-tool recovery max retries, plan execution retry max, terminal evidence gate max retries 계산을 별도 helper로 분리했다.
+  - [AgentLoopService.cs](/E:/AX%20Copilot%20-%20Codex/src/AxCopilot/Services/Agent/AgentLoopService.cs)는 이제 환경 변수/설정값 임계치 계산 로직을 직접 들고 있지 않고 helper를 통해 소비한다.
+- 구조 효과
+  - transcript 렌더링과 tool streaming 복구 정책의 책임 경계가 더 분명해졌다.
+  - 이후 남은 큰 작업인 `진짜 transcript 가상화`와 `AgentLoopService 추가 분해`를 더 작은 변경 단위로 진행할 수 있는 기반을 마련했다.

src/AxCopilot/Services/Agent/AgentLoopRuntimeThresholds.cs

@@ -0,0 +1,52 @@
+namespace AxCopilot.Services.Agent;
+
+internal static class AgentLoopRuntimeThresholds
+{
+    public static int GetNoToolCallResponseThreshold(int defaultValue)
+        => ResolveThresholdValue(
+            Environment.GetEnvironmentVariable("AXCOPILOT_NOTOOL_RESPONSE_THRESHOLD"),
+            defaultValue,
+            min: 1,
+            max: 6);
+
+    public static int GetNoToolCallRecoveryMaxRetries(int defaultValue)
+        => ResolveThresholdValue(
+            Environment.GetEnvironmentVariable("AXCOPILOT_NOTOOL_RECOVERY_MAX_RETRIES"),
+            defaultValue,
+            min: 0,
+            max: 6);
+
+    public static int GetPlanExecutionRetryMax(int defaultValue)
+        => ResolveThresholdValue(
+            Environment.GetEnvironmentVariable("AXCOPILOT_PLAN_EXECUTION_RETRY_MAX"),
+            defaultValue,
+            min: 0,
+            max: 6);
+
+    public static int GetTerminalEvidenceGateMaxRetries(int defaultValue)
+        => ResolveThresholdValue(
+            Environment.GetEnvironmentVariable("AXCOPILOT_TERMINAL_EVIDENCE_GATE_MAX_RETRIES"),
+            defaultValue,
+            min: 0,
+            max: 3);
+
+    public static int ResolveNoToolCallResponseThreshold(string? envRaw)
+        => ResolveThresholdValue(envRaw, defaultValue: 2, min: 1, max: 6);
+
+    public static int ResolveNoToolCallRecoveryMaxRetries(string? envRaw)
+        => ResolveThresholdValue(envRaw, defaultValue: 3, min: 0, max: 6);
+
+    public static int ResolvePlanExecutionRetryMax(string? envRaw)
+        => ResolveThresholdValue(envRaw, defaultValue: 2, min: 0, max: 6);
+
+    public static int ResolveTerminalEvidenceGateMaxRetries(string? envRaw)
+        => ResolveThresholdValue(envRaw, defaultValue: 1, min: 0, max: 3);
+
+    private static int ResolveThresholdValue(string? raw, int defaultValue, int min, int max)
+    {
+        if (!int.TryParse(raw, out var value))
+            return defaultValue;
+
+        return Math.Clamp(value, min, max);
+    }
+}

src/AxCopilot/Services/Agent/AgentLoopService.cs

@@ -26,6 +26,7 @@ public partial class AgentLoopService
     private readonly LlmService _llm;
     private readonly ToolRegistry _tools;
     private readonly SettingsService _settings;
+    private readonly StreamingToolExecutionCoordinator _toolExecutionCoordinator;
     private readonly ConcurrentDictionary<string, PermissionPromptPreview> _pendingPermissionPreviews = new(StringComparer.OrdinalIgnoreCase);
 
     /// <summary>에이전트 이벤트 스트림 (UI 바인딩용).</summary>
@@ -79,6 +80,21 @@ public partial class AgentLoopService
         _llm = llm;
         _tools = tools;
         _settings = settings;
+        _toolExecutionCoordinator = new StreamingToolExecutionCoordinator(
+            _llm,
+            ResolveRequestedToolName,
+            async (toolName, input, context, messages, ct) =>
+            {
+                var tool = _tools.Get(toolName);
+                return tool == null
+                    ? ToolResult.Fail($"도구를 찾을 수 없습니다: {toolName}")
+                    : await ExecuteToolWithTimeoutAsync(tool, toolName, input, context, messages, ct);
+            },
+            (eventType, toolName, summary) => EmitEvent(eventType, toolName, summary),
+            IsContextOverflowError,
+            ForceContextRecovery,
+            IsTransientLlmError,
+            ComputeTransientLlmBackoffDelayMs);
     }
 
     public bool TryGetPendingPermissionPreview(string toolName, string target, out PermissionPromptPreview? preview)
@@ -194,11 +210,11 @@ public partial class AgentLoopService
         var taskPolicy = TaskTypePolicy.FromTaskType(taskType);
         var executionPolicy = _llm.GetActiveExecutionPolicy();
         var consecutiveNoToolResponses = 0;
-        var noToolResponseThreshold = GetNoToolCallResponseThreshold(executionPolicy.NoToolResponseThreshold);
+        var noToolResponseThreshold = AgentLoopRuntimeThresholds.GetNoToolCallResponseThreshold(executionPolicy.NoToolResponseThreshold);
-        var noToolRecoveryMaxRetries = GetNoToolCallRecoveryMaxRetries(executionPolicy.NoToolRecoveryMaxRetries);
+        var noToolRecoveryMaxRetries = AgentLoopRuntimeThresholds.GetNoToolCallRecoveryMaxRetries(executionPolicy.NoToolRecoveryMaxRetries);
-        var planExecutionRetryMax = GetPlanExecutionRetryMax(executionPolicy.PlanExecutionRetryMax);
+        var planExecutionRetryMax = AgentLoopRuntimeThresholds.GetPlanExecutionRetryMax(executionPolicy.PlanExecutionRetryMax);
         var documentPlanRetryMax = Math.Max(0, executionPolicy.DocumentPlanRetryMax);
-        var terminalEvidenceGateRetryMax = GetTerminalEvidenceGateMaxRetries(executionPolicy.TerminalEvidenceGateMaxRetries);
+        var terminalEvidenceGateRetryMax = AgentLoopRuntimeThresholds.GetTerminalEvidenceGateMaxRetries(executionPolicy.TerminalEvidenceGateMaxRetries);
         var failedToolHistogram = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
         var runState = new RunState();
         var requireHighImpactCodeVerification = false;
@@ -3675,58 +3691,6 @@ public partial class AgentLoopService
                 .Select(x => $"{x.Key}({x.Value})"));
     }
 
-    private static int GetNoToolCallResponseThreshold()
-        => GetNoToolCallResponseThreshold(defaultValue: 2);
-
-    private static int GetNoToolCallResponseThreshold(int defaultValue)
-        => ResolveThresholdValue(
-            Environment.GetEnvironmentVariable("AXCOPILOT_NOTOOL_RESPONSE_THRESHOLD"),
-            defaultValue,
-            min: 1,
-            max: 6);
-
-    private static int GetNoToolCallRecoveryMaxRetries()
-        => GetNoToolCallRecoveryMaxRetries(defaultValue: 3);
-
-    private static int GetNoToolCallRecoveryMaxRetries(int defaultValue)
-        => ResolveThresholdValue(
-            Environment.GetEnvironmentVariable("AXCOPILOT_NOTOOL_RECOVERY_MAX_RETRIES"),
-            defaultValue,
-            min: 0,
-            max: 6);
-
-    private static int GetPlanExecutionRetryMax()
-        => GetPlanExecutionRetryMax(defaultValue: 2);
-
-    private static int GetPlanExecutionRetryMax(int defaultValue)
-        => ResolveThresholdValue(
-            Environment.GetEnvironmentVariable("AXCOPILOT_PLAN_EXECUTION_RETRY_MAX"),
-            defaultValue,
-            min: 0,
-            max: 6);
-
-    private static int ResolveNoToolCallResponseThreshold(string? envRaw)
-        => ResolveThresholdValue(envRaw, defaultValue: 2, min: 1, max: 6);
-
-    private static int ResolveNoToolCallRecoveryMaxRetries(string? envRaw)
-        => ResolveThresholdValue(envRaw, defaultValue: 3, min: 0, max: 6);
-
-    private static int ResolvePlanExecutionRetryMax(string? envRaw)
-        => ResolveThresholdValue(envRaw, defaultValue: 2, min: 0, max: 6);
-
-    private static int GetTerminalEvidenceGateMaxRetries()
-        => GetTerminalEvidenceGateMaxRetries(defaultValue: 1);
-
-    private static int GetTerminalEvidenceGateMaxRetries(int defaultValue)
-        => ResolveThresholdValue(
-            Environment.GetEnvironmentVariable("AXCOPILOT_TERMINAL_EVIDENCE_GATE_MAX_RETRIES"),
-            defaultValue,
-            min: 0,
-            max: 3);
-
-    private static int ResolveTerminalEvidenceGateMaxRetries(string? envRaw)
-        => ResolveThresholdValue(envRaw, defaultValue: 1, min: 0, max: 3);
-
     private static string BuildUnknownToolRecoveryPrompt(
         string unknownToolName,
         IReadOnlyCollection<string> activeToolNames)

src/AxCopilot/Services/Agent/AgentLoopTransitions.Execution.cs

@@ -1110,53 +1110,12 @@ public partial class AgentLoopService
         }
     }
 
-    private static readonly HashSet<string> PrefetchableReadOnlyTools = new(StringComparer.OrdinalIgnoreCase)
-    {
-        "file_read", "glob", "grep", "grep_tool", "folder_map", "document_read",
-        "search_codebase", "code_search", "env_tool", "datetime_tool",
-        "dev_env_detect", "memory", "json_tool", "regex_tool", "base64_tool",
-        "hash_tool", "image_analyze", "multi_read"
-    };
-
     private async Task<LlmService.ToolPrefetchResult?> TryPrefetchReadOnlyToolAsync(
         LlmService.ContentBlock block,
         IReadOnlyCollection<IAgentTool> tools,
         AgentContext context,
         CancellationToken ct)
-    {
+        => await _toolExecutionCoordinator.TryPrefetchReadOnlyToolAsync(block, tools, context, ct);
-        var activeToolNames = tools.Select(t => t.Name).Distinct(StringComparer.OrdinalIgnoreCase).ToList();
-        var resolvedToolName = ResolveRequestedToolName(block.ToolName, activeToolNames);
-        block.ResolvedToolName = resolvedToolName;
-
-        if (!PrefetchableReadOnlyTools.Contains(resolvedToolName))
-            return null;
-
-        var tool = _tools.Get(resolvedToolName);
-        if (tool == null)
-            return null;
-
-        EmitEvent(
-            AgentEventType.Thinking,
-            resolvedToolName,
-            $"읽기 도구 조기 실행 준비: {resolvedToolName}");
-
-        var sw = Stopwatch.StartNew();
-        try
-        {
-            var input = block.ToolInput ?? JsonDocument.Parse("{}").RootElement;
-            var result = await ExecuteToolWithTimeoutAsync(tool, resolvedToolName, input, context, null, ct);
-            sw.Stop();
-            return new LlmService.ToolPrefetchResult(result, sw.ElapsedMilliseconds, resolvedToolName);
-        }
-        catch (Exception ex)
-        {
-            sw.Stop();
-            return new LlmService.ToolPrefetchResult(
-                ToolResult.Fail($"조기 실행 오류: {ex.Message}"),
-                sw.ElapsedMilliseconds,
-                resolvedToolName);
-        }
-    }
 
     private async Task<List<LlmService.ContentBlock>> SendWithToolsWithRecoveryAsync(
         List<ChatMessage> messages,
@@ -1167,75 +1126,15 @@ public partial class AgentLoopService
         bool forceToolCall = false,
         Func<LlmService.ContentBlock, Task<LlmService.ToolPrefetchResult?>>? prefetchToolCallAsync = null,
         Func<LlmService.ToolStreamEvent, Task>? onStreamEventAsync = null)
-    {
+        => await _toolExecutionCoordinator.SendWithToolsWithRecoveryAsync(
-        var transientRetries = runState?.TransientLlmErrorRetries ?? 0;
+            messages,
-        var contextRecoveryRetries = runState?.ContextRecoveryAttempts ?? 0;
+            tools,
-        while (true)
+            ct,
-        {
+            phaseLabel,
-            try
+            runState,
-            {
+            forceToolCall,
-                if (onStreamEventAsync == null)
+            prefetchToolCallAsync,
-                    return await _llm.SendWithToolsAsync(messages, tools, ct, forceToolCall, prefetchToolCallAsync);
+            onStreamEventAsync);
-
-                var blocks = new List<LlmService.ContentBlock>();
-                var textBuilder = new StringBuilder();
-                await foreach (var evt in _llm.StreamWithToolsAsync(messages, tools, forceToolCall, prefetchToolCallAsync, ct).WithCancellation(ct))
-                {
-                    await onStreamEventAsync(evt);
-                    if (evt.Kind == LlmService.ToolStreamEventKind.TextDelta && !string.IsNullOrWhiteSpace(evt.Text))
-                    {
-                        textBuilder.Append(evt.Text);
-                    }
-                    else if (evt.Kind == LlmService.ToolStreamEventKind.ToolCallReady && evt.ToolCall != null)
-                    {
-                        blocks.Add(evt.ToolCall);
-                    }
-                }
-
-                var result = new List<LlmService.ContentBlock>();
-                var text = textBuilder.ToString().Trim();
-                if (!string.IsNullOrWhiteSpace(text))
-                    result.Add(new LlmService.ContentBlock { Type = "text", Text = text });
-                result.AddRange(blocks);
-                return result;
-            }
-            catch (Exception ex)
-            {
-                if (IsContextOverflowError(ex.Message)
-                    && contextRecoveryRetries < 2
-                    && ForceContextRecovery(messages))
-                {
-                    contextRecoveryRetries++;
-                    if (runState != null)
-                        runState.ContextRecoveryAttempts = contextRecoveryRetries;
-                    EmitEvent(
-                        AgentEventType.Thinking,
-                        "",
-                        $"{phaseLabel}: 컨텍스트 한도 초과로 대화를 압축한 후 재시도합니다 ({contextRecoveryRetries}/2)");
-                    continue;
-                }
-
-                // 사용자 취소(ct)인 경우 재시도하지 않고 즉시 전파
-                if (ct.IsCancellationRequested) throw;
-
-                if (IsTransientLlmError(ex) && transientRetries < 3)
-                {
-                    transientRetries++;
-                    if (runState != null)
-                        runState.TransientLlmErrorRetries = transientRetries;
-                    var delayMs = ComputeTransientLlmBackoffDelayMs(transientRetries, ex);
-                    EmitEvent(
-                        AgentEventType.Thinking,
-                        "",
-                        $"{phaseLabel}: 일시적 LLM 오류로 {delayMs}ms 후 재시도합니다 ({transientRetries}/3)");
-                    await Task.Delay(delayMs, ct);
-                    continue;
-                }
-
-                throw;
-            }
-        }
-    }
 
     private void ApplyToolPostExecutionBookkeeping(
         LlmService.ContentBlock call,
@@ -1651,7 +1550,7 @@ public partial class AgentLoopService
         return (false, null);
     }
 
-    private sealed class RunState
+    internal sealed class RunState
     {
         public int ContextRecoveryAttempts;
         public int WithheldRecoveryAttempts;

src/AxCopilot/Services/Agent/StreamingToolExecutionCoordinator.cs

@@ -0,0 +1,166 @@
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Text;
+using System.Text.Json;
+using AxCopilot.Models;
+using AxCopilot.Services;
+
+namespace AxCopilot.Services.Agent;
+
+internal sealed class StreamingToolExecutionCoordinator
+{
+    private static readonly HashSet<string> PrefetchableReadOnlyTools = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "file_read", "glob", "grep", "grep_tool", "folder_map", "document_read",
+        "search_codebase", "code_search", "env_tool", "datetime_tool",
+        "dev_env_detect", "memory", "json_tool", "regex_tool", "base64_tool",
+        "hash_tool", "image_analyze", "multi_read"
+    };
+
+    private readonly LlmService _llm;
+    private readonly Func<string, IReadOnlyCollection<string>, string> _resolveRequestedToolName;
+    private readonly Func<string, JsonElement, AgentContext, List<ChatMessage>?, CancellationToken, Task<ToolResult>> _executeToolAsync;
+    private readonly Action<AgentEventType, string, string> _emitEvent;
+    private readonly Func<string?, bool> _isContextOverflowError;
+    private readonly Func<List<ChatMessage>, bool> _forceContextRecovery;
+    private readonly Func<Exception, bool> _isTransientLlmError;
+    private readonly Func<int, Exception, int> _computeTransientBackoffDelayMs;
+
+    public StreamingToolExecutionCoordinator(
+        LlmService llm,
+        Func<string, IReadOnlyCollection<string>, string> resolveRequestedToolName,
+        Func<string, JsonElement, AgentContext, List<ChatMessage>?, CancellationToken, Task<ToolResult>> executeToolAsync,
+        Action<AgentEventType, string, string> emitEvent,
+        Func<string?, bool> isContextOverflowError,
+        Func<List<ChatMessage>, bool> forceContextRecovery,
+        Func<Exception, bool> isTransientLlmError,
+        Func<int, Exception, int> computeTransientBackoffDelayMs)
+    {
+        _llm = llm;
+        _resolveRequestedToolName = resolveRequestedToolName;
+        _executeToolAsync = executeToolAsync;
+        _emitEvent = emitEvent;
+        _isContextOverflowError = isContextOverflowError;
+        _forceContextRecovery = forceContextRecovery;
+        _isTransientLlmError = isTransientLlmError;
+        _computeTransientBackoffDelayMs = computeTransientBackoffDelayMs;
+    }
+
+    public async Task<LlmService.ToolPrefetchResult?> TryPrefetchReadOnlyToolAsync(
+        LlmService.ContentBlock block,
+        IReadOnlyCollection<IAgentTool> tools,
+        AgentContext context,
+        CancellationToken ct)
+    {
+        var activeToolNames = tools.Select(t => t.Name).Distinct(StringComparer.OrdinalIgnoreCase).ToList();
+        var resolvedToolName = _resolveRequestedToolName(block.ToolName, activeToolNames);
+        block.ResolvedToolName = resolvedToolName;
+
+        if (!PrefetchableReadOnlyTools.Contains(resolvedToolName))
+            return null;
+
+        _emitEvent(
+            AgentEventType.Thinking,
+            resolvedToolName,
+            $"읽기 도구 조기 실행 준비: {resolvedToolName}");
+
+        var sw = Stopwatch.StartNew();
+        try
+        {
+            var input = block.ToolInput ?? JsonDocument.Parse("{}").RootElement;
+            var result = await _executeToolAsync(resolvedToolName, input, context, null, ct);
+            sw.Stop();
+            return new LlmService.ToolPrefetchResult(result, sw.ElapsedMilliseconds, resolvedToolName);
+        }
+        catch (Exception ex)
+        {
+            sw.Stop();
+            return new LlmService.ToolPrefetchResult(
+                ToolResult.Fail($"조기 실행 오류: {ex.Message}"),
+                sw.ElapsedMilliseconds,
+                resolvedToolName);
+        }
+    }
+
+    public async Task<List<LlmService.ContentBlock>> SendWithToolsWithRecoveryAsync(
+        List<ChatMessage> messages,
+        IReadOnlyCollection<IAgentTool> tools,
+        CancellationToken ct,
+        string phaseLabel,
+        AgentLoopService.RunState? runState = null,
+        bool forceToolCall = false,
+        Func<LlmService.ContentBlock, Task<LlmService.ToolPrefetchResult?>>? prefetchToolCallAsync = null,
+        Func<LlmService.ToolStreamEvent, Task>? onStreamEventAsync = null)
+    {
+        var transientRetries = runState?.TransientLlmErrorRetries ?? 0;
+        var contextRecoveryRetries = runState?.ContextRecoveryAttempts ?? 0;
+
+        while (true)
+        {
+            try
+            {
+                if (onStreamEventAsync == null)
+                    return await _llm.SendWithToolsAsync(messages, tools, ct, forceToolCall, prefetchToolCallAsync);
+
+                var blocks = new List<LlmService.ContentBlock>();
+                var textBuilder = new StringBuilder();
+                await foreach (var evt in _llm.StreamWithToolsAsync(messages, tools, forceToolCall, prefetchToolCallAsync, ct).WithCancellation(ct))
+                {
+                    await onStreamEventAsync(evt);
+                    if (evt.Kind == LlmService.ToolStreamEventKind.TextDelta && !string.IsNullOrWhiteSpace(evt.Text))
+                    {
+                        textBuilder.Append(evt.Text);
+                    }
+                    else if (evt.Kind == LlmService.ToolStreamEventKind.ToolCallReady && evt.ToolCall != null)
+                    {
+                        blocks.Add(evt.ToolCall);
+                    }
+                }
+
+                var result = new List<LlmService.ContentBlock>();
+                var text = textBuilder.ToString().Trim();
+                if (!string.IsNullOrWhiteSpace(text))
+                    result.Add(new LlmService.ContentBlock { Type = "text", Text = text });
+                result.AddRange(blocks);
+                return result;
+            }
+            catch (Exception ex)
+            {
+                if (_isContextOverflowError(ex.Message)
+                    && contextRecoveryRetries < 2
+                    && _forceContextRecovery(messages))
+                {
+                    contextRecoveryRetries++;
+                    if (runState != null)
+                        runState.ContextRecoveryAttempts = contextRecoveryRetries;
+
+                    _emitEvent(
+                        AgentEventType.Thinking,
+                        "",
+                        $"{phaseLabel}: 컨텍스트 한도 초과로 대화를 압축한 후 재시도합니다 ({contextRecoveryRetries}/2)");
+                    continue;
+                }
+
+                if (ct.IsCancellationRequested)
+                    throw;
+
+                if (_isTransientLlmError(ex) && transientRetries < 3)
+                {
+                    transientRetries++;
+                    if (runState != null)
+                        runState.TransientLlmErrorRetries = transientRetries;
+
+                    var delayMs = _computeTransientBackoffDelayMs(transientRetries, ex);
+                    _emitEvent(
+                        AgentEventType.Thinking,
+                        "",
+                        $"{phaseLabel}: 일시적 LLM 오류로 {delayMs}ms 후 재시도합니다 ({transientRetries}/3)");
+                    await Task.Delay(delayMs, ct);
+                    continue;
+                }
+
+                throw;
+            }
+        }
+    }
+}

src/AxCopilot/Views/ChatWindow.TranscriptRendering.cs

@@ -0,0 +1,169 @@
+using System.Windows.Threading;
+using AxCopilot.Models;
+using AxCopilot.Services;
+
+namespace AxCopilot.Views;
+
+public partial class ChatWindow
+{
+    private int GetActiveTimelineRenderLimit()
+    {
+        if (!_isStreaming)
+            return _timelineRenderLimit;
+
+        var streamingLimit = IsLightweightLiveProgressMode()
+            ? TimelineLightweightStreamingRenderLimit
+            : TimelineStreamingRenderLimit;
+        return Math.Min(_timelineRenderLimit, streamingLimit);
+    }
+
+    private void RenderMessages(bool preserveViewport = false)
+    {
+        var previousScrollableHeight = GetTranscriptScrollableHeight();
+        var previousVerticalOffset = GetTranscriptVerticalOffset();
+
+        ChatConversation? conv;
+        lock (_convLock) conv = _currentConversation;
+        _appState.RestoreAgentRunHistory(conv?.AgentRunHistory);
+
+        var visibleMessages = GetVisibleTimelineMessages(conv);
+        var visibleEvents = GetVisibleTimelineEvents(conv);
+
+        if (_isStreaming && preserveViewport
+            && visibleMessages.Count == _lastRenderedMessageCount
+            && visibleEvents.Count == _lastRenderedEventCount
+            && (conv?.ShowExecutionHistory ?? true) == _lastRenderedShowHistory
+            && string.Equals(_lastRenderedConversationId, conv?.Id, StringComparison.OrdinalIgnoreCase))
+            return;
+
+        if (conv == null || (visibleMessages.Count == 0 && visibleEvents.Count == 0))
+        {
+            ClearTranscriptElements();
+            _runBannerAnchors.Clear();
+            _lastRenderedTimelineKeys.Clear();
+            _lastRenderedMessageCount = 0;
+            _lastRenderedEventCount = 0;
+            EmptyState.Visibility = System.Windows.Visibility.Visible;
+            return;
+        }
+
+        if (!string.Equals(_lastRenderedConversationId, conv.Id, StringComparison.OrdinalIgnoreCase))
+        {
+            _lastRenderedConversationId = conv.Id;
+            _timelineRenderLimit = TimelineRenderPageSize;
+            _elementCache.Clear();
+            _lastRenderedTimelineKeys.Clear();
+            _lastRenderedMessageCount = 0;
+            _lastRenderedEventCount = 0;
+            InvalidateTimelineCache();
+        }
+
+        var showHistory = conv.ShowExecutionHistory;
+        EmptyState.Visibility = System.Windows.Visibility.Collapsed;
+
+        var orderedTimeline = BuildTimelineRenderActions(visibleMessages, visibleEvents);
+        var effectiveRenderLimit = GetActiveTimelineRenderLimit();
+        var hiddenCount = Math.Max(0, orderedTimeline.Count - effectiveRenderLimit);
+        var visibleTimeline = hiddenCount > 0
+            ? orderedTimeline.GetRange(hiddenCount, orderedTimeline.Count - hiddenCount)
+            : orderedTimeline;
+        var newKeys = new List<string>(visibleTimeline.Count);
+        foreach (var t in visibleTimeline)
+            newKeys.Add(t.Key);
+
+        var incremented = false;
+        var hasExternalChildren = _agentLiveContainer != null && ContainsTranscriptElement(_agentLiveContainer);
+        var expectedChildCount = _lastRenderedTimelineKeys.Count + (_lastRenderedHiddenCount > 0 ? 1 : 0);
+        var canIncremental = !hasExternalChildren
+            && _lastRenderedTimelineKeys.Count > 0
+            && newKeys.Count >= _lastRenderedTimelineKeys.Count
+            && _lastRenderedHiddenCount == hiddenCount
+            && GetTranscriptElementCount() == expectedChildCount;
+
+        if (canIncremental)
+        {
+            var prevLiveCount = 0;
+            for (var i = _lastRenderedTimelineKeys.Count - 1; i >= 0; i--)
+            {
+                if (_lastRenderedTimelineKeys[i].StartsWith("_live_", StringComparison.Ordinal))
+                    prevLiveCount++;
+                else
+                    break;
+            }
+
+            var prevStableCount = _lastRenderedTimelineKeys.Count - prevLiveCount;
+            var prefixMatch = true;
+            for (var i = 0; i < prevStableCount; i++)
+            {
+                if (i >= newKeys.Count || !string.Equals(_lastRenderedTimelineKeys[i], newKeys[i], StringComparison.Ordinal))
+                {
+                    prefixMatch = false;
+                    break;
+                }
+            }
+
+            if (prefixMatch)
+            {
+                try
+                {
+                    for (var r = 0; r < prevLiveCount && GetTranscriptElementCount() > 0; r++)
+                        RemoveTranscriptElementAt(GetTranscriptElementCount() - 1);
+
+                    for (var i = prevStableCount; i < visibleTimeline.Count; i++)
+                        visibleTimeline[i].Render();
+
+                    _lastRenderedTimelineKeys = newKeys;
+                    _lastRenderedHiddenCount = hiddenCount;
+                    _lastRenderedMessageCount = visibleMessages.Count;
+                    _lastRenderedEventCount = visibleEvents.Count;
+                    _lastRenderedShowHistory = showHistory;
+                    incremented = true;
+                }
+                catch (Exception ex)
+                {
+                    LogService.Warn($"증분 렌더링 실패, 전체 재빌드로 전환: {ex.Message}");
+                    _lastRenderedTimelineKeys.Clear();
+                    incremented = false;
+                }
+            }
+        }
+
+        if (!incremented)
+        {
+            ClearTranscriptElements();
+            _runBannerAnchors.Clear();
+
+            if (hiddenCount > 0)
+                AddTranscriptElement(CreateTimelineLoadMoreCard(hiddenCount));
+
+            foreach (var item in visibleTimeline)
+                item.Render();
+
+            if (_agentLiveContainer != null && !ContainsTranscriptElement(_agentLiveContainer))
+                AddTranscriptElement(_agentLiveContainer);
+
+            _lastRenderedTimelineKeys = newKeys;
+            _lastRenderedHiddenCount = hiddenCount;
+            _lastRenderedMessageCount = visibleMessages.Count;
+            _lastRenderedEventCount = visibleEvents.Count;
+            _lastRenderedShowHistory = showHistory;
+        }
+
+        if (!preserveViewport)
+        {
+            _ = Dispatcher.InvokeAsync(ScrollTranscriptToEnd, DispatcherPriority.Background);
+            return;
+        }
+
+        _ = Dispatcher.InvokeAsync(() =>
+        {
+            if (_transcriptScrollViewer == null)
+                return;
+
+            var newScrollableHeight = GetTranscriptScrollableHeight();
+            var delta = newScrollableHeight - previousScrollableHeight;
+            var targetOffset = Math.Max(0, previousVerticalOffset + Math.Max(0, delta));
+            ScrollTranscriptToVerticalOffset(targetOffset);
+        }, DispatcherPriority.Background);
+    }
+}

src/AxCopilot/Views/ChatWindow.xaml.cs

@@ -2284,181 +2284,6 @@ public partial class ChatWindow : Window
     private string? _lastRenderedConversationId;
     private int _timelineRenderLimit = TimelineRenderPageSize;
 
-    private int GetActiveTimelineRenderLimit()
-    {
-        if (!_isStreaming)
-            return _timelineRenderLimit;
-
-        var streamingLimit = IsLightweightLiveProgressMode()
-            ? TimelineLightweightStreamingRenderLimit
-            : TimelineStreamingRenderLimit;
-        return Math.Min(_timelineRenderLimit, streamingLimit);
-    }
-
-    private void RenderMessages(bool preserveViewport = false)
-    {
-        var previousScrollableHeight = GetTranscriptScrollableHeight();
-        var previousVerticalOffset = GetTranscriptVerticalOffset();
-
-        ChatConversation? conv;
-        lock (_convLock) conv = _currentConversation;
-        _appState.RestoreAgentRunHistory(conv?.AgentRunHistory);
-
-        var visibleMessages = GetVisibleTimelineMessages(conv);
-        var visibleEvents = GetVisibleTimelineEvents(conv);
-
-        // 스트리밍 중 메시지·이벤트 수가 동일하면 불필요한 재렌더링 스킵
-        if (_isStreaming && preserveViewport
-            && visibleMessages.Count == _lastRenderedMessageCount
-            && visibleEvents.Count == _lastRenderedEventCount
-            && (conv?.ShowExecutionHistory ?? true) == _lastRenderedShowHistory
-            && string.Equals(_lastRenderedConversationId, conv?.Id, StringComparison.OrdinalIgnoreCase))
-            return;
-
-        if (conv == null || (visibleMessages.Count == 0 && visibleEvents.Count == 0))
-        {
-            ClearTranscriptElements();
-            _runBannerAnchors.Clear();
-            _lastRenderedTimelineKeys.Clear();
-            _lastRenderedMessageCount = 0;
-            _lastRenderedEventCount = 0;
-            EmptyState.Visibility = Visibility.Visible;
-            return;
-        }
-
-        if (!string.Equals(_lastRenderedConversationId, conv.Id, StringComparison.OrdinalIgnoreCase))
-        {
-            _lastRenderedConversationId = conv.Id;
-            _timelineRenderLimit = TimelineRenderPageSize;
-            _elementCache.Clear();
-            _lastRenderedTimelineKeys.Clear();
-            _lastRenderedMessageCount = 0;
-            _lastRenderedEventCount = 0;
-            InvalidateTimelineCache();
-        }
-
-        var showHistory = conv.ShowExecutionHistory;
-
-        EmptyState.Visibility = Visibility.Collapsed;
-
-        var orderedTimeline = BuildTimelineRenderActions(visibleMessages, visibleEvents);
-        var effectiveRenderLimit = GetActiveTimelineRenderLimit();
-        var hiddenCount = Math.Max(0, orderedTimeline.Count - effectiveRenderLimit);
-        var visibleTimeline = hiddenCount > 0
-            ? orderedTimeline.GetRange(hiddenCount, orderedTimeline.Count - hiddenCount)
-            : orderedTimeline;
-        var newKeys = new List<string>(visibleTimeline.Count);
-        foreach (var t in visibleTimeline) newKeys.Add(t.Key);
-
-        var incremented = false;
-
-        // ── 증분 렌더링: 이전 키 목록과 비교하여 변경 최소화 ──
-        // agent live card가 존재하면 Children과 키 불일치 가능 → 전체 재빌드
-        var hasExternalChildren = _agentLiveContainer != null && ContainsTranscriptElement(_agentLiveContainer);
-        var expectedChildCount = _lastRenderedTimelineKeys.Count + (_lastRenderedHiddenCount > 0 ? 1 : 0);
-        var canIncremental = !hasExternalChildren
-            && _lastRenderedTimelineKeys.Count > 0
-            && newKeys.Count >= _lastRenderedTimelineKeys.Count
-            && _lastRenderedHiddenCount == hiddenCount
-            && GetTranscriptElementCount() == expectedChildCount;
-
-        if (canIncremental)
-        {
-            // _live_ 키 개수를 한 번만 계산 (이전 키 목록에서)
-            var prevLiveCount = 0;
-            for (int i = _lastRenderedTimelineKeys.Count - 1; i >= 0; i--)
-            {
-                if (_lastRenderedTimelineKeys[i].StartsWith("_live_", StringComparison.Ordinal))
-                    prevLiveCount++;
-                else
-                    break; // live 키는 항상 끝에 연속으로 위치
-            }
-            var prevStableCount = _lastRenderedTimelineKeys.Count - prevLiveCount;
-
-            // 안정 키(non-live) 접두사가 일치하는지 확인
-            var prefixMatch = true;
-            for (int i = 0; i < prevStableCount; i++)
-            {
-                if (i >= newKeys.Count || !string.Equals(_lastRenderedTimelineKeys[i], newKeys[i], StringComparison.Ordinal))
-                {
-                    prefixMatch = false;
-                    break;
-                }
-            }
-
-            if (prefixMatch)
-            {
-                try
-                {
-                    // 이전 live 요소를 Children 끝에서 제거
-                    for (int r = 0; r < prevLiveCount && GetTranscriptElementCount() > 0; r++)
-                        RemoveTranscriptElementAt(GetTranscriptElementCount() - 1);
-
-                    // 안정 접두사 이후의 새 아이템 렌더링 (새 stable + 새 live 포함)
-                    for (int i = prevStableCount; i < visibleTimeline.Count; i++)
-                        visibleTimeline[i].Render();
-
-                    _lastRenderedTimelineKeys = newKeys;
-                    _lastRenderedHiddenCount = hiddenCount;
-                    _lastRenderedMessageCount = visibleMessages.Count;
-                    _lastRenderedEventCount = visibleEvents.Count;
-                    _lastRenderedShowHistory = showHistory;
-                    incremented = true;
-                }
-                catch (Exception ex)
-                {
-                    LogService.Warn($"증분 렌더링 실패, 전체 재빌드로 전환: {ex.Message}");
-                    _lastRenderedTimelineKeys.Clear();
-                    incremented = false;
-                }
-            }
-        }
-
-        if (!incremented)
-        {
-            // ── 전체 재빌드 (대화 전환, 접기/펴기, 중간 변경 등) ──
-            ClearTranscriptElements();
-            _runBannerAnchors.Clear();
-
-            if (hiddenCount > 0)
-                AddTranscriptElement(CreateTimelineLoadMoreCard(hiddenCount));
-
-            foreach (var item in visibleTimeline)
-                item.Render();
-
-            // 전체 재빌드로 Children이 초기화되었으므로 agent live card 복원
-            if (_agentLiveContainer != null && !ContainsTranscriptElement(_agentLiveContainer))
-                AddTranscriptElement(_agentLiveContainer);
-
-            _lastRenderedTimelineKeys = newKeys;
-            _lastRenderedHiddenCount = hiddenCount;
-            _lastRenderedMessageCount = visibleMessages.Count;
-            _lastRenderedEventCount = visibleEvents.Count;
-            _lastRenderedShowHistory = showHistory;
-        }
-
-        // ── 스크롤 처리 ──
-        if (!preserveViewport)
-        {
-            _ = Dispatcher.InvokeAsync(() =>
-            {
-                ScrollTranscriptToEnd();
-            }, DispatcherPriority.Background);
-            return;
-        }
-
-        _ = Dispatcher.InvokeAsync(() =>
-        {
-            if (_transcriptScrollViewer == null)
-                return;
-
-            var newScrollableHeight = GetTranscriptScrollableHeight();
-            var delta = newScrollableHeight - previousScrollableHeight;
-            var targetOffset = Math.Max(0, previousVerticalOffset + Math.Max(0, delta));
-            ScrollTranscriptToVerticalOffset(targetOffset);
-        }, DispatcherPriority.Background);
-    }
-
     // ─── 커스텀 체크 아이콘 (모든 팝업 메뉴 공통) ─────────────────────────
 
     /// <summary>커스텀 체크/미선택 아이콘을 생성합니다. Path 도형 기반, 선택 시 스케일 바운스 애니메이션.</summary>