[Phase 17-C] 훅 시스템 고도화 — 11종 이벤트 연결 + Prompt 모드 구현

AppSettings.AgentConfig.cs:
- ExtendedHooksConfig에 4개 이벤트 추가:
  preToolUse, postToolUse, postToolUseFailure, agentStop

AgentLoopService.ExtendedHooks.cs (신규, 150줄):
- RunExtendedEventAsync(): 이벤트 훅 실행, 결과(additionalContext) 시스템 메시지 주입, HookFired 이벤트 로그
- GetExtendedHooks(): 설정에서 HookEventKind별 런타임 엔트리 조회
- ConvertToRuntimeEntries(): ExtendedHookEntryConfig → ExtendedHookEntry 변환
- ApplyExtendedHookResult(): additionalContext in-place 주입 (marker 기반 교체)

ExtendedHookRunner.cs:
- RunEventAsync() / ExecuteSingleAsync()에 LlmService? llm 파라미터 추가
- RunPromptHookAsync() 신규: {{tool_name/input/output/user_message/event/session_id}} 치환
  → LLM 호출 → block/deny/차단 감지 시 Block=true 반환
- using AxCopilot.Models 추가

AgentLoopService.cs:
- SessionStart 훅 (fire-and-forget, TaskState init 직후)
- UserPromptSubmit 훅 (동기, Block=true 시 즉시 반환 "⚠ 훅 정책에 의해 차단")
- PreCompact 훅 (적극적 압축 직전, 동기)
- PostCompact 훅 × 2 (기본/적극적 압축 완료 후, fire-and-forget)
- SessionEnd + AgentStop 훅 (finally 블록, fire-and-forget)

AgentLoopService.Execution.cs:
- RunToolHooksAsync() 개선: 레거시 AgentHookRunner 유지
  + ExtendedHookRunner PreToolUse/PostToolUse/PostToolUseFailure 추가
이벤트 커버리지: 11종 완전 연결. Agent 모드는 Phase 18-A 예정.
빌드: 경고 0, 오류 0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/NEXT_ROADMAP.md

@@ -5001,5 +5001,33 @@ ThemeResourceHelper에 5개 정적 필드 추가:
 
 ---
 
-최종 업데이트: 2026-04-03 (Phase 22~52 + Phase 17-UI-A~E + Phase 17-A~B 구현 완료)
+---
+
+## Phase 17-C — 훅 시스템 고도화 (v1.8.0) ✅ 완료
+
+> **목표**: ExtendedHookRunner를 에이전트 라이프사이클 전 구간에 연결 + Prompt 모드 구현
+
+### 변경 파일
+
+| 파일 | 변경 내용 |
+|------|----------|
+| `AppSettings.AgentConfig.cs` | `ExtendedHooksConfig`에 4개 이벤트 추가: `preToolUse`, `postToolUse`, `postToolUseFailure`, `agentStop` |
+| `AgentLoopService.ExtendedHooks.cs` (신규, 150줄) | `RunExtendedEventAsync()` — 이벤트 훅 실행·결과 적용. `GetExtendedHooks()` — 설정에서 런타임 엔트리 조회. `ConvertToRuntimeEntries()` — ExtendedHookEntryConfig → ExtendedHookEntry 변환. `ApplyExtendedHookResult()` — additionalContext 시스템 메시지 in-place 주입. |
+| `ExtendedHookRunner.cs` | `RunEventAsync()` + `ExecuteSingleAsync()`에 `LlmService? llm` 파라미터 추가. `RunPromptHookAsync()` 신규 구현: `{{tool_name}}` 등 변수 치환, LLM 호출, 차단 신호 감지. `using AxCopilot.Models` 추가. |
+| `AgentLoopService.cs` | TaskState init 후: `SessionStart` 훅(fire-and-forget) + `UserPromptSubmit` 훅(차단 시 즉시 반환). 적극적 압축 직전: `PreCompact` 훅. 압축 완료 후: `PostCompact` 훅(fire-and-forget). `finally` 블록: `SessionEnd` + `AgentStop` 훅(fire-and-forget). |
+| `AgentLoopService.Execution.cs` | `RunToolHooksAsync()` 개선: 레거시 AgentHookRunner 유지 + ExtendedHookRunner `PreToolUse`/`PostToolUse`/`PostToolUseFailure` 이벤트 추가 실행. |
+
+### 구현 세부사항
+
+- **이벤트 커버리지**: SessionStart, SessionEnd, AgentStop, UserPromptSubmit, PreToolUse, PostToolUse, PostToolUseFailure, PreCompact, PostCompact, FileChanged, PermissionRequest — 11종 이벤트 완전 연결
+- **실행 모드**: Command(bat/ps1), Http(POST webhook), Prompt(LLM 평가) 구현. Agent 모드는 Phase 18-A 예정.
+- **Prompt 모드**: `{{tool_name}}`, `{{tool_input}}`, `{{tool_output}}`, `{{user_message}}`, `{{event}}`, `{{session_id}}` 변수 치환. 응답에 block/deny/차단 포함 시 Block=true.
+- **차단 처리**: UserPromptSubmit 훅 Block=true 시 즉시 `"⚠ 요청이 훅 정책에 의해 차단되었습니다."` 반환
+- **HookFired 이벤트 로그**: 훅 실행 시 JSONL에 eventKind, hookCount, blocked 기록
+- **하위 호환**: 레거시 AgentHooks(command 스크립트) 병행 유지
+- **빌드**: 경고 0, 오류 0
+
+---
+
+최종 업데이트: 2026-04-04 (Phase 22~52 + Phase 17-UI-A~E + Phase 17-A~C 구현 완료)
 

src/AxCopilot/Models/AppSettings.AgentConfig.cs

@@ -59,24 +59,40 @@ public class ReflexionConfig
 /// <summary>Phase 17-C: 확장 훅 설정.</summary>
 public class ExtendedHooksConfig
 {
+    // ── 라이프사이클 이벤트 ──────────────────────────────────────────────
+    [JsonPropertyName("session_start")]
+    public List<ExtendedHookEntryConfig> SessionStart { get; set; } = new();
+
+    [JsonPropertyName("session_end")]
+    public List<ExtendedHookEntryConfig> SessionEnd { get; set; } = new();
+
+    [JsonPropertyName("agent_stop")]
+    public List<ExtendedHookEntryConfig> AgentStop { get; set; } = new();
+
     [JsonPropertyName("user_prompt_submit")]
     public List<ExtendedHookEntryConfig> UserPromptSubmit { get; set; } = new();
 
+    // ── 도구 이벤트 ─────────────────────────────────────────────────────
+    [JsonPropertyName("pre_tool_use")]
+    public List<ExtendedHookEntryConfig> PreToolUse { get; set; } = new();
+
+    [JsonPropertyName("post_tool_use")]
+    public List<ExtendedHookEntryConfig> PostToolUse { get; set; } = new();
+
+    [JsonPropertyName("post_tool_use_failure")]
+    public List<ExtendedHookEntryConfig> PostToolUseFailure { get; set; } = new();
+
+    // ── 컨텍스트 압축 이벤트 ────────────────────────────────────────────
     [JsonPropertyName("pre_compact")]
     public List<ExtendedHookEntryConfig> PreCompact { get; set; } = new();
 
     [JsonPropertyName("post_compact")]
     public List<ExtendedHookEntryConfig> PostCompact { get; set; } = new();
 
+    // ── 파일·권한 이벤트 ────────────────────────────────────────────────
     [JsonPropertyName("file_changed")]
     public List<ExtendedHookEntryConfig> FileChanged { get; set; } = new();
 
-    [JsonPropertyName("session_start")]
-    public List<ExtendedHookEntryConfig> SessionStart { get; set; } = new();
-
-    [JsonPropertyName("session_end")]
-    public List<ExtendedHookEntryConfig> SessionEnd { get; set; } = new();
-
     [JsonPropertyName("permission_request")]
     public List<ExtendedHookEntryConfig> PermissionRequest { get; set; } = new();
 }

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

@@ -369,27 +369,42 @@ public partial class AgentLoopService
     /// <summary>도구 호출 처리 후 루프 제어 액션.</summary>
     private enum ToolCallAction { Continue, Break, Return }
 
-    /// <summary>Phase 33-B: 도구 훅(Pre/Post) 실행 헬퍼.</summary>
+    /// <summary>Phase 33-B / 17-C: 도구 훅(Pre/Post/Failure) 실행 헬퍼.</summary>
     private async Task RunToolHooksAsync(
         Models.LlmSettings llm, LlmService.ContentBlock call,
         AgentContext context, string phase, CancellationToken ct,
         ToolResult? result = null)
     {
-        if (!llm.EnableToolHooks || llm.AgentHooks.Count == 0) return;
+        // ── 레거시 AgentHooks (command 스크립트, 하위 호환) ──────────────
-        try
+        if (llm.EnableToolHooks && llm.AgentHooks.Count > 0)
         {
-            var hookResults = await AgentHookRunner.RunAsync(
+            try
-                llm.AgentHooks, call.ToolName, phase,
+            {
-                toolInput: call.ToolInput.ToString(),
+                var hookResults = await AgentHookRunner.RunAsync(
-                toolOutput: result != null ? TruncateOutput(result.Output, 2048) : null,
+                    llm.AgentHooks, call.ToolName, phase,
-                success: result?.Success ?? false,
+                    toolInput: call.ToolInput.ToString(),
-                workFolder: context.WorkFolder,
+                    toolOutput: result != null ? TruncateOutput(result.Output, 2048) : null,
-                timeoutMs: llm.ToolHookTimeoutMs,
+                    success: result?.Success ?? false,
-                ct: ct);
+                    workFolder: context.WorkFolder,
-            foreach (var pr in hookResults.Where(r => !r.Success))
+                    timeoutMs: llm.ToolHookTimeoutMs,
-                EmitEvent(AgentEventType.Error, call.ToolName, $"[Hook:{pr.HookName}] {pr.Output}");
+                    ct: ct);
+                foreach (var pr in hookResults.Where(r => !r.Success))
+                    EmitEvent(AgentEventType.Error, call.ToolName, $"[Hook:{pr.HookName}] {pr.Output}");
+            }
+            catch (Exception ex) { LogService.Warn($"[AgentLoop] {phase}ToolUse 레거시 훅 실패: {ex.Message}"); }
         }
-        catch (Exception ex) { LogService.Warn($"[AgentLoop] {phase}ToolUse 훅 실패: {ex.Message}"); }
+
+        // ── Phase 17-C: 확장 훅 (ExtendedHooks — command/http/prompt 모드) ──
+        var extKind = phase == "pre"
+            ? HookEventKind.PreToolUse
+            : (result?.Success == false ? HookEventKind.PostToolUseFailure : HookEventKind.PostToolUse);
+
+        await RunExtendedEventAsync(
+            extKind, null, ct,
+            toolName:   call.ToolName,
+            toolInput:  call.ToolInput?.ToString(),
+            toolOutput: result != null ? TruncateOutput(result.Output, 2048) : null,
+            toolSuccess: result?.Success ?? true);
     }
 
     /// <summary>DelegateAgentTool에서 호출하는 서브에이전트 실행기.</summary>

src/AxCopilot/Services/Agent/AgentLoopService.ExtendedHooks.cs

@@ -0,0 +1,158 @@
+using AxCopilot.Models;
+
+namespace AxCopilot.Services.Agent;
+
+/// <summary>
+/// Phase 17-C: AgentLoopService — 확장 훅 시스템 통합.
+/// 에이전트 라이프사이클 이벤트(SessionStart/End, UserPromptSubmit,
+/// PreToolUse/PostToolUse, PreCompact/PostCompact 등)에
+/// ExtendedHookRunner를 연결합니다.
+/// </summary>
+public partial class AgentLoopService
+{
+    /// <summary>
+    /// 지정 이벤트의 확장 훅을 실행합니다.
+    /// - additionalContext가 있으면 시스템 메시지에 주입
+    /// - Block인 경우 true 반환 → 호출자가 작업을 중단해야 함
+    /// </summary>
+    internal async Task<bool> RunExtendedEventAsync(
+        HookEventKind kind,
+        List<ChatMessage>? messages,
+        CancellationToken ct,
+        string? toolName = null,
+        string? toolInput = null,
+        string? toolOutput = null,
+        bool toolSuccess = true,
+        string? userMessage = null,
+        string? changedFile = null)
+    {
+        var hooks = GetExtendedHooks(kind);
+        if (hooks.Count == 0) return false;
+
+        var ctx = new HookContext
+        {
+            Event          = kind,
+            ToolName       = toolName,
+            ToolInput      = toolInput,
+            ToolOutput     = toolOutput,
+            ToolSuccess    = toolSuccess,
+            UserMessage    = userMessage,
+            ChangedFilePath = changedFile,
+            SessionId      = _sessionId,
+            WorkFolder     = _settings.Settings.Llm.WorkFolder ?? "",
+        };
+
+        try
+        {
+            var result = await ExtendedHookRunner.RunEventAsync(hooks, ctx, ct, _llm);
+            ApplyExtendedHookResult(result, messages);
+
+            // HookFired 이벤트 로그 기록
+            if (_eventLog != null && hooks.Count > 0)
+                _ = _eventLog.AppendAsync(AgentEventLogType.HookFired,
+                    System.Text.Json.JsonSerializer.Serialize(new
+                    {
+                        eventKind = kind.ToString(),
+                        hookCount = hooks.Count,
+                        blocked   = result.Block
+                    }));
+
+            return result.Block;
+        }
+        catch (Exception ex)
+        {
+            LogService.Warn($"[ExtendedHook] {kind} 훅 실행 오류: {ex.Message}");
+            return false;
+        }
+    }
+
+    /// <summary>훅 결과의 additionalContext를 시스템 메시지에 주입합니다.</summary>
+    private static void ApplyExtendedHookResult(ExtendedHookResult result, List<ChatMessage>? messages)
+    {
+        if (string.IsNullOrEmpty(result.AdditionalContext) || messages == null) return;
+
+        const string marker = "[Hook Context]";
+        var sysMsg = messages.FirstOrDefault(m => m.Role == "system");
+        if (sysMsg != null)
+        {
+            // 기존 [Hook Context] 섹션 교체 (중복 방지)
+            var idx = sysMsg.Content.IndexOf(marker, StringComparison.Ordinal);
+            if (idx >= 0)
+                sysMsg.Content = sysMsg.Content[..idx] + marker + "\n" + result.AdditionalContext;
+            else
+                sysMsg.Content += $"\n\n{marker}\n{result.AdditionalContext}";
+        }
+        else
+        {
+            messages.Insert(0, new ChatMessage
+            {
+                Role    = "system",
+                Content = $"{marker}\n{result.AdditionalContext}"
+            });
+        }
+    }
+
+    // ─────────────────────────────────────────────────────────────────────
+    //  설정 → 런타임 엔트리 변환
+    // ─────────────────────────────────────────────────────────────────────
+
+    /// <summary>설정에서 특정 이벤트의 활성 훅 엔트리 목록을 반환합니다.</summary>
+    private List<ExtendedHookEntry> GetExtendedHooks(HookEventKind kind)
+    {
+        var cfg = _settings.Settings.Llm.ExtendedHooks;
+
+        IReadOnlyList<ExtendedHookEntryConfig>? configs = kind switch
+        {
+            HookEventKind.SessionStart       => cfg.SessionStart,
+            HookEventKind.SessionEnd         => cfg.SessionEnd,
+            HookEventKind.AgentStop          => cfg.AgentStop,
+            HookEventKind.UserPromptSubmit   => cfg.UserPromptSubmit,
+            HookEventKind.PreToolUse         => cfg.PreToolUse,
+            HookEventKind.PostToolUse        => cfg.PostToolUse,
+            HookEventKind.PostToolUseFailure => cfg.PostToolUseFailure,
+            HookEventKind.PreCompact         => cfg.PreCompact,
+            HookEventKind.PostCompact        => cfg.PostCompact,
+            HookEventKind.FileChanged        => cfg.FileChanged,
+            HookEventKind.PermissionRequest  => cfg.PermissionRequest,
+            _                                => null
+        };
+
+        if (configs == null || configs.Count == 0) return new List<ExtendedHookEntry>();
+        return ConvertToRuntimeEntries(configs, kind);
+    }
+
+    /// <summary>설정 모델(ExtendedHookEntryConfig) → 런타임 모델(ExtendedHookEntry) 변환.</summary>
+    private static List<ExtendedHookEntry> ConvertToRuntimeEntries(
+        IReadOnlyList<ExtendedHookEntryConfig> configs, HookEventKind kind)
+    {
+        return configs
+            .Where(c => c.Enabled)
+            .Select(c => new ExtendedHookEntry
+            {
+                Name           = c.Name,
+                Event          = kind,
+                Matcher        = c.Matcher,
+                Mode           = ParseMode(c.Mode),
+                ScriptPath     = c.ScriptPath,
+                Url            = c.Url,
+                Prompt         = c.Prompt,
+                Model          = c.Model,
+                Enabled        = c.Enabled,
+                Once           = c.Once,
+                IsAsync        = c.IsAsync,
+                TimeoutSeconds = c.TimeoutSeconds > 0 ? c.TimeoutSeconds : 30,
+                StatusMessage  = c.StatusMessage,
+                WatchPaths     = c.WatchPaths ?? new List<string>(),
+            })
+            .ToList();
+    }
+
+    private static HookExecutionMode ParseMode(string? mode) =>
+        mode?.ToLowerInvariant() switch
+        {
+            "http"   => HookExecutionMode.Http,
+            "prompt" => HookExecutionMode.Prompt,
+            "agent"  => HookExecutionMode.Agent,
+            _        => HookExecutionMode.Command
+        };
+}

src/AxCopilot/Services/Agent/AgentLoopService.cs

@@ -176,6 +176,23 @@ public partial class AgentLoopService
             _ = _eventLog?.AppendAsync(AgentEventLogType.UserMessage,
                 JsonSerializer.Serialize(new { length = userQuery.Length }));
         await InitTaskStateAsync(userQuery, _sessionId);
+
+        // Phase 17-C: SessionStart 훅 실행 (fire-and-forget)
+        _ = RunExtendedEventAsync(HookEventKind.SessionStart, messages, CancellationToken.None,
+            userMessage: userQuery);
+
+        // Phase 17-C: UserPromptSubmit 훅 실행 — 차단 시 즉시 종료
+        if (!string.IsNullOrWhiteSpace(userQuery))
+        {
+            var promptBlocked = await RunExtendedEventAsync(
+                HookEventKind.UserPromptSubmit, messages, ct, userMessage: userQuery);
+            if (promptBlocked)
+            {
+                EmitEvent(AgentEventType.Complete, "", "훅 정책에 의해 요청이 차단되었습니다");
+                return "⚠ 요청이 훅 정책에 의해 차단되었습니다.";
+            }
+        }
+
         var consecutiveErrors = 0; // Self-Reflection: 연속 오류 카운터
         var totalToolCalls = 0;    // 복잡도 추정용
 
@@ -357,6 +374,8 @@ public partial class AgentLoopService
                         _ = _eventLog?.AppendAsync(AgentEventLogType.CompactionCompleted,
                             JsonSerializer.Serialize(new { messageCount = messages.Count }));
                         UpdateTaskStateSummaryAsync("컨텍스트 압축 완료");
+                        // Phase 17-C: PostCompact 훅 (fire-and-forget)
+                        _ = RunExtendedEventAsync(HookEventKind.PostCompact, messages, CancellationToken.None);
                     }
 
                     // 임계치 기반 적극적 압축 (이전 LLM 호출의 토큰 사용량 기준)
@@ -374,6 +393,8 @@ public partial class AgentLoopService
                                 $"⚠ 컨텍스트 사용량 {usagePct}% — 적극적 컴팩션 실행");
                             _ = _eventLog?.AppendAsync(AgentEventLogType.CompactionTriggered,
                                 JsonSerializer.Serialize(new { aggressive = true, usagePct }));
+                            // Phase 17-C: PreCompact 훅 — 적극적 압축 직전 (압축 발생 확실)
+                            await RunExtendedEventAsync(HookEventKind.PreCompact, messages, ct);
                             var targetTokens = (int)(llm.MaxContextTokens * Defaults.ContextCompressionTargetRatio);
                             var compacted = await ContextCondenser.CondenseIfNeededAsync(
                                 messages, _llm, targetTokens, ct);
@@ -383,6 +404,8 @@ public partial class AgentLoopService
                                 _ = _eventLog?.AppendAsync(AgentEventLogType.CompactionCompleted,
                                     JsonSerializer.Serialize(new { aggressive = true, messageCount = messages.Count }));
                                 UpdateTaskStateSummaryAsync($"적극적 컴팩션 완료 (이전 컨텍스트 사용량 {usagePct}%)");
+                                // Phase 17-C: PostCompact 훅 (fire-and-forget)
+                                _ = RunExtendedEventAsync(HookEventKind.PostCompact, messages, CancellationToken.None);
                             }
                         }
                     }
@@ -778,6 +801,10 @@ public partial class AgentLoopService
         }
         finally
         {
+            // Phase 17-C: SessionEnd + AgentStop 확장 훅 실행 (fire-and-forget)
+            _ = RunExtendedEventAsync(HookEventKind.SessionEnd,   null, CancellationToken.None, userMessage: userQuery);
+            _ = RunExtendedEventAsync(HookEventKind.AgentStop,    null, CancellationToken.None, userMessage: userQuery);
+
             // 세션 종료 이벤트 기록
             if (_eventLog != null)
                 _ = _eventLog.AppendAsync(AgentEventLogType.SessionEnd,

src/AxCopilot/Services/Agent/ExtendedHookRunner.cs

@@ -3,6 +3,7 @@ using System.IO;
 using System.Net.Http;
 using System.Text;
 using System.Text.Json;
+using AxCopilot.Models;
 
 namespace AxCopilot.Services.Agent;
 
@@ -22,10 +23,12 @@ public static class ExtendedHookRunner
     };
 
     /// <summary>지정 이벤트의 훅을 모두 실행하고 결과를 병합하여 반환.</summary>
+    /// <param name="llm">Prompt 모드 훅에서 LLM 호출에 사용할 서비스 (null이면 Prompt 모드 스킵).</param>
     public static async Task<ExtendedHookResult> RunEventAsync(
         IReadOnlyList<ExtendedHookEntry> hooks,
         HookContext context,
-        CancellationToken ct = default)
+        CancellationToken ct = default,
+        LlmService? llm = null)
     {
         if (hooks == null || hooks.Count == 0)
             return new ExtendedHookResult();
@@ -53,7 +56,7 @@ public static class ExtendedHookRunner
                 {
                     try
                     {
-                        var result = await ExecuteSingleAsync(hook, context, CancellationToken.None);
+                        var result = await ExecuteSingleAsync(hook, context, CancellationToken.None, llm);
                         if (result.Block)
                         {
                             // exit code 2 = rewake → AdditionalContext를 통해 대화 재활성화
@@ -72,7 +75,7 @@ public static class ExtendedHookRunner
             {
                 _ = Task.Run(async () =>
                 {
-                    try { await ExecuteSingleAsync(hook, context, CancellationToken.None); }
+                    try { await ExecuteSingleAsync(hook, context, CancellationToken.None, llm); }
                     catch (Exception) { }
                 });
             }
@@ -95,7 +98,7 @@ public static class ExtendedHookRunner
 
             try
             {
-                var result = await ExecuteSingleAsync(hook, context, cts.Token);
+                var result = await ExecuteSingleAsync(hook, context, cts.Token, llm);
 
                 if (result.Block) { anyBlocked = true; blockReason = result.BlockReason; break; }
                 if (result.AdditionalContext != null)
@@ -130,18 +133,70 @@ public static class ExtendedHookRunner
     private static async Task<ExtendedHookResult> ExecuteSingleAsync(
         ExtendedHookEntry hook,
         HookContext context,
-        CancellationToken ct)
+        CancellationToken ct,
+        LlmService? llm = null)
     {
         return hook.Mode switch
         {
             HookExecutionMode.Command => await RunCommandHookAsync(hook, context, ct),
             HookExecutionMode.Http    => await RunHttpHookAsync(hook, context, ct),
-            HookExecutionMode.Prompt  => new ExtendedHookResult(), // LLM 검사는 LlmService 필요 — 외부에서 처리
+            // Phase 17-C: Prompt 모드 — LlmService 주입 필요. 없으면 스킵.
-            HookExecutionMode.Agent   => new ExtendedHookResult(), // 미니 에이전트는 AgentLoopService 필요 — 외부 처리
+            HookExecutionMode.Prompt  => llm != null
+                ? await RunPromptHookAsync(hook, context, llm, ct)
+                : new ExtendedHookResult(),
+            // Agent 모드: AgentLoopService 참조 필요 — 미구현 (향후 Phase 18-A에서 처리)
+            HookExecutionMode.Agent   => new ExtendedHookResult(),
             _ => new ExtendedHookResult()
         };
     }
 
+    /// <summary>
+    /// Phase 17-C: Prompt 모드 훅 — LLM으로 도구/이벤트를 평가합니다.
+    /// 프롬프트에서 {{tool_name}}, {{tool_input}}, {{tool_output}}, {{user_message}} 치환.
+    /// 응답에 "block", "deny", "차단" 포함 시 Block=true 반환.
+    /// </summary>
+    private static async Task<ExtendedHookResult> RunPromptHookAsync(
+        ExtendedHookEntry hook,
+        HookContext context,
+        LlmService llm,
+        CancellationToken ct)
+    {
+        if (string.IsNullOrWhiteSpace(hook.Prompt)) return new ExtendedHookResult();
+
+        // 변수 치환
+        var evalPrompt = hook.Prompt
+            .Replace("{{tool_name}}",    context.ToolName    ?? "", StringComparison.OrdinalIgnoreCase)
+            .Replace("{{tool_input}}",   context.ToolInput   ?? "", StringComparison.OrdinalIgnoreCase)
+            .Replace("{{tool_output}}",  context.ToolOutput  ?? "", StringComparison.OrdinalIgnoreCase)
+            .Replace("{{user_message}}", context.UserMessage ?? "", StringComparison.OrdinalIgnoreCase)
+            .Replace("{{event}}",        context.Event.ToString(), StringComparison.OrdinalIgnoreCase)
+            .Replace("{{session_id}}",   context.SessionId,        StringComparison.OrdinalIgnoreCase);
+
+        string response;
+        try
+        {
+            var messages = new List<ChatMessage>
+            {
+                new() { Role = "user", Content = evalPrompt }
+            };
+            // 훅 전용 소형 모델이 지정된 경우 → 현재는 기본 LLM 사용 (향후 모델 오버라이드 지원 예정)
+            response = await llm.SendAsync(messages, ct);
+        }
+        catch (Exception)
+        {
+            return new ExtendedHookResult();
+        }
+
+        if (string.IsNullOrWhiteSpace(response)) return new ExtendedHookResult();
+
+        // 차단 신호 감지
+        var lower = response.ToLowerInvariant();
+        if (lower.Contains("block") || lower.Contains("deny") || lower.Contains("차단"))
+            return new ExtendedHookResult { Block = true, BlockReason = Truncate(response, 500) };
+
+        return new ExtendedHookResult { AdditionalContext = Truncate(response, 2000) };
+    }
+
     private static async Task<ExtendedHookResult> RunCommandHookAsync(
         ExtendedHookEntry hook,
         HookContext context,