fix: improve thread safety in tool registry

- Use thread-safe registry.unregister() in remove_tool()
- Use thread-safe registry.list_tools() in list_tools()
- Add double-checked locking to get_registry() singleton
- Prevents race conditions in multi-agent deployments

Related to #1167 and closed PR #1182

Co-authored-by: Mervin Praison <MervinPraison@users.noreply.github.com>

Author: github-actions[bot]

src/praisonai-agents/praisonaiagents/tools/registry.py

@@ -249,15 +249,19 @@ def __repr__(self) -> str:
         return f"ToolRegistry(tools={len(self._tools)}, functions={len(self._functions)})"
 
 
-# Global registry instance
+# Global registry instance (protected by _registry_lock for thread safety)
+_registry_lock = threading.Lock()
 _global_registry: Optional[ToolRegistry] = None
 
 
 def get_registry() -> ToolRegistry:
-    """Get the global tool registry instance."""
+    """Get the global tool registry instance. Thread-safe singleton."""
     global _global_registry
     if _global_registry is None:
-        _global_registry = ToolRegistry()
+        with _registry_lock:
+            # Double-checked locking pattern
+            if _global_registry is None:
+                _global_registry = ToolRegistry()
     return _global_registry
 
 
@@ -309,14 +313,7 @@ def remove_tool(name: str) -> bool:
     Returns:
         True if tool was found and removed, False otherwise
     """
-    registry = get_registry()
-    if name in registry._tools:
-        del registry._tools[name]
-        return True
-    if name in registry._functions:
-        del registry._functions[name]
-        return True
-    return False
+    return get_registry().unregister(name)
 
 
 def list_tools() -> List[str]:
@@ -325,8 +322,7 @@ def list_tools() -> List[str]:
     Returns:
         List of tool names
     """
-    registry = get_registry()
-    return list(registry._tools.keys()) + list(registry._functions.keys())
+    return get_registry().list_tools()
 
 
 def discover_plugins() -> int: