diff --git a/src/google/adk/agents/llm_agent.py b/src/google/adk/agents/llm_agent.py
index a5c859e26..2a215b1e0 100644
--- a/src/google/adk/agents/llm_agent.py
+++ b/src/google/adk/agents/llm_agent.py
@@ -23,6 +23,7 @@
 from typing import Literal
 from typing import Optional
 from typing import Union
+from typing import Sequence
 
 from google.genai import types
 from pydantic import BaseModel
@@ -135,7 +136,7 @@ class LlmAgent(BaseAgent):
   or personality.
   """
 
-  tools: list[ToolUnion] = Field(default_factory=list)
+  tools: Sequence[ToolUnion] = Field(default_factory=list)
   """Tools available to this agent."""
 
   generate_content_config: Optional[types.GenerateContentConfig] = None