diff --git a/auto-claude-ui/src/main/task-log-service.ts b/auto-claude-ui/src/main/task-log-service.ts
index 8cd46a63..7fa0de77 100644
--- a/auto-claude-ui/src/main/task-log-service.ts
+++ b/auto-claude-ui/src/main/task-log-service.ts
@@ -32,6 +32,7 @@ export class TaskLogService extends EventEmitter {
 
   /**
    * Load task logs from a single spec directory
+   * Returns cached logs if the file is corrupted (e.g., mid-write by Python backend)
    */
   loadLogsFromPath(specDir: string): TaskLogs | null {
     const logFile = path.join(specDir, 'task_logs.json');
@@ -45,6 +46,13 @@ export class TaskLogService extends EventEmitter {
       const logs = JSON.parse(content) as TaskLogs;
       return logs;
     } catch (error) {
+      // JSON parse error - file may be mid-write, return cached version if available
+      const cached = this.logCache.get(specDir);
+      if (cached) {
+        // Silently return cached version - this is expected during concurrent access
+        return cached;
+      }
+      // Only log if we have no cached fallback
       console.error(`[TaskLogService] Failed to load logs from ${logFile}:`, error);
       return null;
     }
diff --git a/auto-claude/task_logger/storage.py b/auto-claude/task_logger/storage.py
index ba2605e9..6e50e89d 100644
--- a/auto-claude/task_logger/storage.py
+++ b/auto-claude/task_logger/storage.py
@@ -3,7 +3,9 @@ Storage functionality for task logs.
 """
 
 import json
+import os
 import sys
+import tempfile
 from datetime import datetime, timezone
 from pathlib import Path
 
@@ -65,12 +67,25 @@ class LogStorage:
         }
 
     def save(self) -> None:
-        """Save logs to file."""
+        """Save logs to file atomically to prevent corruption from concurrent reads."""
         self._data["updated_at"] = self._timestamp()
         try:
             self.spec_dir.mkdir(parents=True, exist_ok=True)
-            with open(self.log_file, "w", encoding="utf-8") as f:
-                json.dump(self._data, f, indent=2, ensure_ascii=False)
+            # Write to temp file first, then atomic rename to prevent corruption
+            # when the UI reads mid-write
+            fd, tmp_path = tempfile.mkstemp(
+                dir=self.spec_dir, prefix=".task_logs_", suffix=".tmp"
+            )
+            try:
+                with os.fdopen(fd, "w", encoding="utf-8") as f:
+                    json.dump(self._data, f, indent=2, ensure_ascii=False)
+                # Atomic rename (on POSIX systems, rename is atomic)
+                os.replace(tmp_path, self.log_file)
+            except Exception:
+                # Clean up temp file on failure
+                if os.path.exists(tmp_path):
+                    os.unlink(tmp_path)
+                raise
         except OSError as e:
             print(f"Warning: Failed to save task logs: {e}", file=sys.stderr)