diff --git a/runners/agent-runner/src/index.ts b/runners/agent-runner/src/index.ts
index a7e8c32..8df9b46 100644
--- a/runners/agent-runner/src/index.ts
+++ b/runners/agent-runner/src/index.ts
@@ -32,7 +32,7 @@ interface ContainerInput {
 
 interface ContainerOutput {
   status: 'success' | 'error';
-  phase?: 'progress' | 'final';
+  phase?: 'progress' | 'final' | 'tool-activity';
   result: string | null;
   newSessionId?: string;
   error?: string;
@@ -554,6 +554,7 @@ async function runQuery(
     if (message.type === 'system' && (message as { subtype?: string }).subtype === 'task_progress') {
       const tp = message as Record<string, unknown>;
       const summary = typeof tp.summary === 'string' ? tp.summary : '';
+      const description = typeof tp.description === 'string' ? tp.description : '';
       if (summary) {
         log(`Subagent progress: ${summary.slice(0, 200)}`);
         writeOutput({
@@ -563,6 +564,14 @@ async function runQuery(
           newSessionId,
         });
       }
+      if (description) {
+        writeOutput({
+          status: 'success',
+          phase: 'tool-activity',
+          result: description,
+          newSessionId,
+        });
+      }
     }
 
     if (message.type === 'system' && (message as { subtype?: string }).subtype === 'task_started') {
diff --git a/src/agent-runner.ts b/src/agent-runner.ts
index c7da5e4..37bba21 100644
--- a/src/agent-runner.ts
+++ b/src/agent-runner.ts
@@ -41,7 +41,7 @@ export interface AgentInput {
 export interface AgentOutput {
   status: 'success' | 'error';
   result: string | null;
-  phase?: 'progress' | 'final';
+  phase?: 'progress' | 'final' | 'tool-activity';
   newSessionId?: string;
   error?: string;
 }
@@ -238,7 +238,11 @@ export async function runAgentProcess(
       const lines = chunk.trim().split('\n');
       for (const line of lines) {
         if (!line) continue;
-        if (line.includes('Turn in progress') || line.includes('Subagent') || line.includes('Intermediate assistant')) {
+        if (
+          line.includes('Turn in progress') ||
+          line.includes('Subagent') ||
+          line.includes('Intermediate assistant')
+        ) {
           logger.info(
             { group: group.name, chatJid: input.chatJid, runId: input.runId },
             line.replace(/^\[.*?\]\s*/, ''),
diff --git a/src/message-turn-controller.ts b/src/message-turn-controller.ts
index bfb7e88..1303c62 100644
--- a/src/message-turn-controller.ts
+++ b/src/message-turn-controller.ts
@@ -28,6 +28,7 @@ export class MessageTurnController {
   private latestProgressText: string | null = null;
   private previousProgressText: string | null = null;
   private pendingProgressText: string | null = null;
+  private toolActivities: string[] = [];
   private latestProgressRendered: string | null = null;
   private progressMessageId: string | null = null;
   private progressStartedAt: number | null = null;
@@ -103,6 +104,16 @@ export class MessageTurnController {
       );
     }
 
+    if (result.phase === 'tool-activity') {
+      if (text) {
+        this.addToolActivity(text);
+      }
+      if (!this.poisonedSessionDetected) {
+        this.resetIdleTimer();
+      }
+      return;
+    }
+
     if (result.phase === 'progress') {
       if (text) {
         this.bufferProgress(text);
@@ -217,11 +228,14 @@ export class MessageTurnController {
     if (minutes > 0) elapsedParts.push(`${minutes}분`);
     elapsedParts.push(`${seconds}초`);
 
+    const activityLines = this.toolActivities.length > 0
+      ? '\n' + this.toolActivities.map((a) => `├ ${a}`).join('\n')
+      : '';
     const suffix = `\n\n${elapsedParts.join(' ')}`;
-    const maxText = 2000 - TASK_STATUS_MESSAGE_PREFIX.length - suffix.length;
+    const maxText = 2000 - TASK_STATUS_MESSAGE_PREFIX.length - activityLines.length - suffix.length;
     const truncated =
       text.length > maxText ? text.slice(0, maxText - 1) + '…' : text;
-    return `${TASK_STATUS_MESSAGE_PREFIX}${truncated}${suffix}`;
+    return `${TASK_STATUS_MESSAGE_PREFIX}${truncated}${activityLines}${suffix}`;
   }
 
   private clearProgressTicker(): void {
@@ -233,6 +247,7 @@ export class MessageTurnController {
   private resetProgressState(): void {
     this.clearProgressTicker();
     this.pendingProgressText = null;
+    this.toolActivities = [];
     this.latestProgressText = null;
     this.previousProgressText = null;
     this.latestProgressRendered = null;
@@ -252,6 +267,22 @@ export class MessageTurnController {
       void this.sendProgressMessage(this.pendingProgressText);
     }
     this.pendingProgressText = text;
+    this.toolActivities = [];
+  }
+
+  /**
+   * Append a tool activity line and update the progress message in-place.
+   */
+  private addToolActivity(description: string): void {
+    const MAX_ACTIVITIES = 5;
+    this.toolActivities.push(description);
+    if (this.toolActivities.length > MAX_ACTIVITIES) {
+      this.toolActivities = this.toolActivities.slice(-MAX_ACTIVITIES);
+    }
+    // Update the displayed progress message with tool activity sub-lines
+    if (this.latestProgressText && this.progressMessageId) {
+      void this.syncTrackedProgressMessage();
+    }
   }
 
   /**