diff --git a/langchain/agents/tools.py b/langchain/agents/tools.py
index 99e9b741f9f..28593e96766 100644
--- a/langchain/agents/tools.py
+++ b/langchain/agents/tools.py
@@ -38,13 +38,13 @@ class InvalidTool(BaseTool):
     name = "invalid_tool"
     description = "Called when tool name is invalid."
 
-    def _run(self, tool_name: str) -> str:
+    def _run(self, tool_input: str) -> str:
         """Use the tool."""
-        return f"{tool_name} is not a valid tool, try another one."
+        return f"{tool_input} is not a valid tool, try another one."
 
-    async def _arun(self, tool_name: str) -> str:
+    async def _arun(self, tool_input: str) -> str:
         """Use the tool asynchronously."""
-        return f"{tool_name} is not a valid tool, try another one."
+        return f"{tool_input} is not a valid tool, try another one."
 
 
 def tool(*args: Union[str, Callable], return_direct: bool = False) -> Callable:
diff --git a/langchain/tools/base.py b/langchain/tools/base.py
index 4fbb477e806..8f82fbffc2a 100644
--- a/langchain/tools/base.py
+++ b/langchain/tools/base.py
@@ -63,7 +63,7 @@ class BaseTool(ABC, BaseModel):
     ) -> str:
         """Run the tool."""
         if isinstance(tool_input, str):
-            if len(self.args) > 0:
+            if len(self.args) > 1:
                 raise ValueError("Cannot call run on tools with > 1 argument")
             key = self.args[0].name
             run_input = {key: tool_input}
@@ -100,7 +100,7 @@ class BaseTool(ABC, BaseModel):
     ) -> str:
         """Run the tool asynchronously."""
         if isinstance(tool_input, str):
-            if len(self.args) > 0:
+            if len(self.args) > 1:
                 raise ValueError("Cannot call run on tools with > 1 argument")
             key = self.args[0].name
             run_input = {key: tool_input}
diff --git a/langchain/tools/python/tool.py b/langchain/tools/python/tool.py
index 81339cedc34..70aaefe2adb 100644
--- a/langchain/tools/python/tool.py
+++ b/langchain/tools/python/tool.py
@@ -28,13 +28,13 @@ class PythonREPLTool(BaseTool):
     python_repl: PythonREPL = Field(default_factory=_get_default_python_repl)
     sanitize_input: bool = True
 
-    def _run(self, query: str) -> str:
+    def _run(self, tool_input: str) -> str:
         """Use the tool."""
         if self.sanitize_input:
-            query = query.strip().strip("```")
-        return self.python_repl.run(query)
+            tool_input = tool_input.strip().strip("```")
+        return self.python_repl.run(tool_input)
 
-    async def _arun(self, query: str) -> str:
+    async def _arun(self, tool_input: str) -> str:
         """Use the tool asynchronously."""
         raise NotImplementedError("PythonReplTool does not support async")
 
@@ -64,13 +64,13 @@ class PythonAstREPLTool(BaseTool):
             )
         return values
 
-    def _run(self, query: str) -> str:
+    def _run(self, tool_input: str) -> str:
         """Use the tool."""
         try:
             if self.sanitize_input:
                 # Remove the triple backticks from the query.
-                query = query.strip().strip("```")
-            tree = ast.parse(query)
+                tool_input = tool_input.strip().strip("```")
+            tree = ast.parse(tool_input)
             module = ast.Module(tree.body[:-1], type_ignores=[])
             exec(ast.unparse(module), self.globals, self.locals)  # type: ignore
             module_end = ast.Module(tree.body[-1:], type_ignores=[])
@@ -91,6 +91,6 @@ class PythonAstREPLTool(BaseTool):
         except Exception as e:
             return str(e)
 
-    async def _arun(self, query: str) -> str:
+    async def _arun(self, tool_input: str) -> str:
         """Use the tool asynchronously."""
         raise NotImplementedError("PythonReplTool does not support async")