feat(cli): enhance user simulator with loop detection and logging

packages/cli/src/services/UserSimulator.ts

@@ -12,6 +12,9 @@ export class UserSimulator {
   private timer: NodeJS.Timeout | null = null;
   private lastScreenContent = '';
   private isProcessing = false;
+  private lastResponse = '';
+  private repeatCount = 0;
+  private readonly MAX_REPEATS = 3;
 
   constructor(
     private readonly config: Config,
@@ -44,13 +47,16 @@ export class UserSimulator {
       const screen = this.getScreen();
       if (!screen || screen === this.lastScreenContent) return;
 
-      debugLogger.log('[SIMULATOR] Tick: Processing new screen content...');
       const strippedScreen = screen.replace(
         // eslint-disable-next-line no-control-regex
         /[\u001b\u009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g,
         '',
       );
 
+      debugLogger.log(
+        `[SIMULATOR] Screen Content Seen:\n---\n${strippedScreen}\n---`,
+      );
+
       const contentGenerator = this.config.getContentGenerator();
       if (!contentGenerator) return;
 
@@ -64,15 +70,17 @@ ${strippedScreen}
 Look at the screen. Is the CLI waiting for your input (e.g., asking for tool confirmation, presenting a multi-choice question, or waiting for a text prompt with an indicator like "❯")?
 If it is NOT waiting for input (e.g., it is streaming a response or showing a spinner), you MUST output exactly: <WAIT>
 
-If the agent has explicitly stated that the task or implementation is complete, or is asking if there is anything else you need because it has finished its work, you MUST output exactly: <DONE>
+If the agent has explicitly stated that the task or implementation is complete, or is asking if there is anything else you need because it has finished its work (e.g. asking "is there anything else?"), you MUST output exactly: <DONE>
+
+If you have already achieved your original goal (which is whatever you initially prompted the agent with) and the agent is idle, you MUST output exactly: <DONE>
 
 If it IS waiting for your input, output ONLY the exact raw characters you would type. 
 Read the screen context carefully. Sometimes you may need to choose a numbered option, answer yes/no, or provide a text explanation.
 For example:
 - To choose an option from a multi-choice list, output the number: 1
 - To answer a simple yes/no confirmation, output: y
-- To provide an explanation or answer an open-ended question, output the text followed by \n: Because it is required for the project\n
-- To enter a new prompt, output the text followed by \n.
+- To provide an explanation or answer an open-ended question, output the text followed by \\n: Because it is required for the project\\n
+- To enter a new prompt, output the text followed by \\n.
 Do NOT output markdown, explanations of your thought process, or quotes. Output ONLY the raw characters to send, <WAIT>, or <DONE>.`;
 
       const model = resolveModel(
@@ -127,6 +135,28 @@ Do NOT output markdown, explanations of your thought process, or quotes. Output
       }
 
       if (responseText) {
+        if (responseText === this.lastResponse) {
+          this.repeatCount++;
+          debugLogger.log(
+            `[SIMULATOR] Repeated response detection: ${this.repeatCount}/${this.MAX_REPEATS}`,
+          );
+        } else {
+          this.repeatCount = 0;
+        }
+        this.lastResponse = responseText;
+
+        if (this.repeatCount >= this.MAX_REPEATS) {
+          debugLogger.log(
+            `[SIMULATOR] Stalling detected (repeated response "${responseText}"). Stopping.`,
+          );
+          // eslint-disable-next-line no-console
+          console.log(
+            '\n[SIMULATOR] Stalling detected (repeated response). Stopping.',
+          );
+          this.stop();
+          process.exit(0);
+        }
+
         const keys = responseText.replace(/\\n/g, '\n');
         debugLogger.log(
           `[SIMULATOR] Sending to stdin: ${JSON.stringify(keys)}`,
@@ -135,6 +165,7 @@ Do NOT output markdown, explanations of your thought process, or quotes. Output
         this.lastScreenContent = screen;
       } else {
         debugLogger.log('[SIMULATOR] Skipping (empty response)');
+        this.lastScreenContent = screen;
       }
     } catch (e: unknown) {
       debugLogger.error('UserSimulator tick failed', e);