diff --git a/CLAUDE.md b/CLAUDE.md
index dc5b7243..df63f292 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -17,7 +17,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 Claudeman is a Claude Code session manager with a web interface and autonomous Ralph Loop. It spawns Claude CLI processes via PTY, streams output in real-time via SSE, and supports scheduled/timed runs.
 
-**Version**: 0.1341
+**Version**: 0.1342
 
 **Tech Stack**: TypeScript (ES2022/NodeNext, strict mode), Node.js, Fastify, Server-Sent Events, node-pty
 
diff --git a/package.json b/package.json
index c3e269fd..a0cf60a3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "claudeman",
-  "version": "0.1341",
+  "version": "0.1342",
   "description": "The missing control plane for Claude Code - run 20 autonomous agents with real-time monitoring and session persistence",
   "type": "module",
   "main": "dist/index.js",
diff --git a/src/ai-idle-checker.ts b/src/ai-idle-checker.ts
index 3bcb1696..edb74c1c 100644
--- a/src/ai-idle-checker.ts
+++ b/src/ai-idle-checker.ts
@@ -143,6 +143,7 @@ export class AiIdleChecker extends EventEmitter {
   // Active check state
   private checkScreenName: string | null = null;
   private checkTempFile: string | null = null;
+  private checkPromptFile: string | null = null;
   private checkPollTimer: NodeJS.Timeout | null = null;
   private checkTimeoutTimer: NodeJS.Timeout | null = null;
   private checkStartTime: number = 0;
@@ -312,21 +313,25 @@ export class AiIdleChecker extends EventEmitter {
     // Build the prompt
     const prompt = AI_CHECK_PROMPT.replace('{TERMINAL_BUFFER}', trimmed);
 
-    // Generate temp file and screen name
+    // Generate temp files and screen name
     const shortId = this.sessionId.slice(0, 8);
     const timestamp = Date.now();
     this.checkTempFile = join(tmpdir(), `claudeman-aicheck-${shortId}-${timestamp}.txt`);
+    this.checkPromptFile = join(tmpdir(), `claudeman-aicheck-prompt-${shortId}-${timestamp}.txt`);
     this.checkScreenName = `claudeman-aicheck-${shortId}`;
 
-    // Ensure temp file exists (empty) so we can poll it
+    // Ensure output temp file exists (empty) so we can poll it
     writeFileSync(this.checkTempFile, '');
 
-    // Build the command - escape the prompt for shell
-    const escapedPrompt = prompt.replace(/'/g, "'\\''");
+    // Write prompt to file to avoid E2BIG error (argument list too long)
+    // The prompt can be 16KB+ which exceeds shell argument limits
+    writeFileSync(this.checkPromptFile, prompt);
+
+    // Build the command - read prompt from file via stdin to avoid argument size limits
     const modelArg = `--model ${this.config.model}`;
     const augmentedPath = getAugmentedPath();
-    const claudeCmd = `claude -p ${modelArg} --output-format text '${escapedPrompt}'`;
-    const fullCmd = `export PATH="${augmentedPath}"; ${claudeCmd} > "${this.checkTempFile}" 2>&1; echo "${DONE_MARKER}" >> "${this.checkTempFile}"`;
+    const claudeCmd = `cat "${this.checkPromptFile}" | claude -p ${modelArg} --output-format text`;
+    const fullCmd = `export PATH="${augmentedPath}"; ${claudeCmd} > "${this.checkTempFile}" 2>&1; echo "${DONE_MARKER}" >> "${this.checkTempFile}"; rm -f "${this.checkPromptFile}"`;
 
     // Spawn screen
     try {
@@ -430,7 +435,7 @@ export class AiIdleChecker extends EventEmitter {
       this.checkScreenName = null;
     }
 
-    // Delete temp file
+    // Delete temp files
     if (this.checkTempFile) {
       try {
         if (existsSync(this.checkTempFile)) {
@@ -441,6 +446,17 @@ export class AiIdleChecker extends EventEmitter {
       }
       this.checkTempFile = null;
     }
+
+    if (this.checkPromptFile) {
+      try {
+        if (existsSync(this.checkPromptFile)) {
+          unlinkSync(this.checkPromptFile);
+        }
+      } catch {
+        // Best effort cleanup
+      }
+      this.checkPromptFile = null;
+    }
   }
 
   private handleError(errorMsg: string): void {