fix(cli): prevent duplicate rendering of auto-approved file tools (#782)

Co-authored-by: Letta <noreply@letta.com>

src/utils/debug.ts

@@ -1,5 +1,9 @@
 // src/utils/debug.ts
 // Simple debug logging utility - only logs when LETTA_DEBUG env var is set
+// Optionally logs to a file when LETTA_DEBUG_FILE is set
+
+import { appendFileSync } from "node:fs";
+import { format } from "node:util";
 
 /**
  * Check if debug mode is enabled via LETTA_DEBUG env var
@@ -10,6 +14,30 @@ export function isDebugEnabled(): boolean {
   return debug === "1" || debug === "true";
 }
 
+function getDebugFile(): string | null {
+  const path = process.env.LETTA_DEBUG_FILE;
+  return path && path.trim().length > 0 ? path : null;
+}
+
+function writeDebugLine(
+  prefix: string,
+  message: string,
+  args: unknown[],
+): void {
+  const debugFile = getDebugFile();
+  const line = `${format(`[${prefix}] ${message}`, ...args)}\n`;
+  if (debugFile) {
+    try {
+      appendFileSync(debugFile, line, { encoding: "utf8" });
+      return;
+    } catch {
+      // Fall back to console if file write fails
+    }
+  }
+  // Default to console output
+  console.log(line.trimEnd());
+}
+
 /**
  * Log a debug message (only if LETTA_DEBUG is enabled)
  * @param prefix - A prefix/tag for the log message (e.g., "check-approval")
@@ -22,7 +50,7 @@ export function debugLog(
   ...args: unknown[]
 ): void {
   if (isDebugEnabled()) {
-    console.log(`[${prefix}] ${message}`, ...args);
+    writeDebugLine(prefix, message, args);
   }
 }
 
@@ -38,6 +66,6 @@ export function debugWarn(
   ...args: unknown[]
 ): void {
   if (isDebugEnabled()) {
-    console.warn(`[${prefix}] ${message}`, ...args);
+    writeDebugLine(prefix, `WARN: ${message}`, args);
   }
 }