diff --git a/src/constants/toolLimits.ts b/src/constants/toolLimits.ts
index c9706316b..83760af92 100644
--- a/src/constants/toolLimits.ts
+++ b/src/constants/toolLimits.ts
@@ -15,3 +15,5 @@ export const BASH_TRUNCATE_MAX_FILE_BYTES = 1024 * 1024; // 1MB file limit (same
 export const BASH_MAX_LINE_BYTES = 1024; // 1KB per line for AI agent
 
 export const MAX_TODOS = 7; // Maximum number of TODO items in a list
+
+export const STATUS_MESSAGE_MAX_LENGTH = 60; // Maximum length for status messages (auto-truncated)
diff --git a/src/services/tools/status_set.test.ts b/src/services/tools/status_set.test.ts
index 36e6d7daf..e8ea73b50 100644
--- a/src/services/tools/status_set.test.ts
+++ b/src/services/tools/status_set.test.ts
@@ -3,6 +3,7 @@ import { createStatusSetTool } from "./status_set";
 import type { ToolConfiguration } from "@/utils/tools/tools";
 import { createRuntime } from "@/runtime/runtimeFactory";
 import type { ToolCallOptions } from "ai";
+import { STATUS_MESSAGE_MAX_LENGTH } from "@/constants/toolLimits";
 
 describe("status_set tool validation", () => {
   const mockConfig: ToolConfiguration = {
@@ -140,14 +141,15 @@ describe("status_set tool validation", () => {
   });
 
   describe("message validation", () => {
-    it("should accept messages up to 40 characters", async () => {
+    it(`should accept messages up to ${STATUS_MESSAGE_MAX_LENGTH} characters`, async () => {
       const tool = createStatusSetTool(mockConfig);
 
       const result1 = (await tool.execute!(
-        { emoji: "✅", message: "a".repeat(40) },
+        { emoji: "✅", message: "a".repeat(STATUS_MESSAGE_MAX_LENGTH) },
         mockToolCallOptions
-      )) as { success: boolean };
+      )) as { success: boolean; message: string };
       expect(result1.success).toBe(true);
+      expect(result1.message).toBe("a".repeat(STATUS_MESSAGE_MAX_LENGTH));
 
       const result2 = (await tool.execute!(
         { emoji: "✅", message: "Analyzing code structure" },
@@ -156,6 +158,30 @@ describe("status_set tool validation", () => {
       expect(result2.success).toBe(true);
     });
 
+    it(`should truncate messages longer than ${STATUS_MESSAGE_MAX_LENGTH} characters with ellipsis`, async () => {
+      const tool = createStatusSetTool(mockConfig);
+
+      // Test with MAX_LENGTH + 1 characters
+      const result1 = (await tool.execute!(
+        { emoji: "✅", message: "a".repeat(STATUS_MESSAGE_MAX_LENGTH + 1) },
+        mockToolCallOptions
+      )) as { success: boolean; message: string };
+      expect(result1.success).toBe(true);
+      expect(result1.message).toBe("a".repeat(STATUS_MESSAGE_MAX_LENGTH - 1) + "…");
+      expect(result1.message.length).toBe(STATUS_MESSAGE_MAX_LENGTH);
+
+      // Test with longer message
+      const longMessage =
+        "This is a very long message that exceeds the 60 character limit and should be truncated";
+      const result2 = (await tool.execute!(
+        { emoji: "✅", message: longMessage },
+        mockToolCallOptions
+      )) as { success: boolean; message: string };
+      expect(result2.success).toBe(true);
+      expect(result2.message).toBe(longMessage.slice(0, STATUS_MESSAGE_MAX_LENGTH - 1) + "…");
+      expect(result2.message.length).toBe(STATUS_MESSAGE_MAX_LENGTH);
+    });
+
     it("should accept empty message", async () => {
       const tool = createStatusSetTool(mockConfig);
 
diff --git a/src/services/tools/status_set.ts b/src/services/tools/status_set.ts
index 14a499402..ac0ca36a8 100644
--- a/src/services/tools/status_set.ts
+++ b/src/services/tools/status_set.ts
@@ -1,6 +1,7 @@
 import { tool } from "ai";
 import type { ToolFactory } from "@/utils/tools/tools";
 import { TOOL_DEFINITIONS } from "@/utils/tools/toolDefinitions";
+import { STATUS_MESSAGE_MAX_LENGTH } from "@/constants/toolLimits";
 
 /**
  * Result type for status_set tool
@@ -38,6 +39,17 @@ function isValidEmoji(str: string): boolean {
   return emojiRegex.test(segments[0].segment);
 }
 
+/**
+ * Truncates a message to a maximum length, adding an ellipsis if truncated
+ */
+function truncateMessage(message: string, maxLength: number): string {
+  if (message.length <= maxLength) {
+    return message;
+  }
+  // Truncate to maxLength-1 and add ellipsis (total = maxLength)
+  return message.slice(0, maxLength - 1) + "…";
+}
+
 /**
  * Status set tool factory for AI assistant
  * Creates a tool that allows the AI to set status indicator showing current activity
@@ -62,12 +74,15 @@ export const createStatusSetTool: ToolFactory = () => {
         });
       }
 
+      // Truncate message if necessary
+      const truncatedMessage = truncateMessage(message, STATUS_MESSAGE_MAX_LENGTH);
+
       // Tool execution is a no-op on the backend
       // The status is tracked by StreamingMessageAggregator and displayed in the frontend
       return Promise.resolve({
         success: true,
         emoji,
-        message,
+        message: truncatedMessage,
       });
     },
   });
diff --git a/src/utils/messages/StreamingMessageAggregator.status.test.ts b/src/utils/messages/StreamingMessageAggregator.status.test.ts
index ad1617688..5609c8b2b 100644
--- a/src/utils/messages/StreamingMessageAggregator.status.test.ts
+++ b/src/utils/messages/StreamingMessageAggregator.status.test.ts
@@ -494,4 +494,49 @@ describe("StreamingMessageAggregator - Agent Status", () => {
     // Status should remain undefined (failed validation)
     expect(aggregator.getAgentStatus()).toBeUndefined();
   });
+
+  it("should use truncated message from output, not original input", () => {
+    const aggregator = new StreamingMessageAggregator(new Date().toISOString());
+
+    const messageId = "msg1";
+    const toolCallId = "tool1";
+
+    // Start stream
+    aggregator.handleStreamStart({
+      type: "stream-start",
+      workspaceId: "workspace1",
+      messageId,
+      model: "test-model",
+      historySequence: 1,
+    });
+
+    // Status_set with long message (would be truncated by backend)
+    const longMessage = "a".repeat(100); // 100 chars, exceeds 60 char limit
+    const truncatedMessage = "a".repeat(59) + "…"; // What backend returns
+
+    aggregator.handleToolCallStart({
+      type: "tool-call-start",
+      workspaceId: "workspace1",
+      messageId,
+      toolCallId,
+      toolName: "status_set",
+      args: { emoji: "✅", message: longMessage },
+      tokens: 10,
+      timestamp: Date.now(),
+    });
+
+    aggregator.handleToolCallEnd({
+      type: "tool-call-end",
+      workspaceId: "workspace1",
+      messageId,
+      toolCallId,
+      toolName: "status_set",
+      result: { success: true, emoji: "✅", message: truncatedMessage },
+    });
+
+    // Should use truncated message from output, not the original input
+    const status = aggregator.getAgentStatus();
+    expect(status).toEqual({ emoji: "✅", message: truncatedMessage });
+    expect(status?.message.length).toBe(60);
+  });
 });
diff --git a/src/utils/messages/StreamingMessageAggregator.ts b/src/utils/messages/StreamingMessageAggregator.ts
index 1af90a9ac..9954b8361 100644
--- a/src/utils/messages/StreamingMessageAggregator.ts
+++ b/src/utils/messages/StreamingMessageAggregator.ts
@@ -520,9 +520,10 @@ export class StreamingMessageAggregator {
     }
 
     // Update agent status if this was a successful status_set
+    // Use output instead of input to get the truncated message
     if (toolName === "status_set" && hasSuccessResult(output)) {
-      const args = input as { emoji: string; message: string };
-      this.agentStatus = { emoji: args.emoji, message: args.message };
+      const result = output as { success: true; emoji: string; message: string };
+      this.agentStatus = { emoji: result.emoji, message: result.message };
     }
   }
 
diff --git a/src/utils/tools/toolDefinitions.ts b/src/utils/tools/toolDefinitions.ts
index 2e106a011..8eea68fe0 100644
--- a/src/utils/tools/toolDefinitions.ts
+++ b/src/utils/tools/toolDefinitions.ts
@@ -11,6 +11,7 @@ import {
   BASH_HARD_MAX_LINES,
   BASH_MAX_LINE_BYTES,
   BASH_MAX_TOTAL_BYTES,
+  STATUS_MESSAGE_MAX_LENGTH,
 } from "@/constants/toolLimits";
 
 import { zodToJsonSchema } from "zod-to-json-schema";
@@ -193,8 +194,9 @@ export const TOOL_DEFINITIONS = {
         emoji: z.string().describe("A single emoji character representing the current activity"),
         message: z
           .string()
-          .max(40)
-          .describe("A brief description of the current activity (max 40 characters)"),
+          .describe(
+            `A brief description of the current activity (auto-truncated to ${STATUS_MESSAGE_MAX_LENGTH} chars with ellipsis if needed)`
+          ),
       })
       .strict(),
   },