diff --git a/astrbot/core/star/context.py b/astrbot/core/star/context.py
index 593bad9365..56007edf05 100644
--- a/astrbot/core/star/context.py
+++ b/astrbot/core/star/context.py
@@ -491,15 +491,23 @@ def add_llm_tools(self, *tools: FunctionTool) -> None:
         for tool in tools:
             if not module_path:
                 _parts = []
-                module_part = tool.__module__.split(".")
+                module_part = tool.__module__.split(".") if tool.__module__ else []
                 flags = ["builtin_stars", "plugins"]
+                found_flag = False
                 for i, part in enumerate(module_part):
                     _parts.append(part)
                     if part in flags and i + 1 < len(module_part):
                         _parts.append(module_part[i + 1])
                         _parts.append("main")
+                        found_flag = True
                         break
-                tool.handler_module_path = ".".join(_parts)
+                if not found_flag and module_part:
+                    # Subdirectory tool: construct path matching star_manager format
+                    # Only apply to known plugin naming patterns (astrbot_plugin_*)
+                    plugin_name = module_part[0]
+                    if plugin_name.startswith("astrbot_plugin_"):
+                        _parts = ["data", "plugins", plugin_name, "main"]
+                tool.handler_module_path = ".".join(_parts) if _parts else tool.__module__ or ""
                 module_path = tool.handler_module_path
             else:
                 tool.handler_module_path = module_path