diff --git a/src/game_sdk/game/agent.py b/src/game_sdk/game/agent.py
index e38071b4..8642849f 100644
--- a/src/game_sdk/game/agent.py
+++ b/src/game_sdk/game/agent.py
@@ -121,6 +121,12 @@ def __init__(self,
         # initialize session
         self._session = Session()
 
+        # Input validation for character limits
+        if len(agent_goal.replace(" ", "")) > 1500:
+            raise ValueError("Agent goal must not exceed 1500 characters")
+        if len(agent_description.replace(" ", "")) > 3000:
+            raise ValueError("Agent description must not exceed 3000 characters")
+
         self.name = name
         self.agent_goal = agent_goal
         self.agent_description = agent_description
diff --git a/src/game_sdk/hosted_game/agent.py b/src/game_sdk/hosted_game/agent.py
index e4ece771..539f9f37 100644
--- a/src/game_sdk/hosted_game/agent.py
+++ b/src/game_sdk/hosted_game/agent.py
@@ -32,6 +32,12 @@ class FunctionConfig:
     platform: str = None
 
     def __post_init__(self):
+        # Validate feedback character limits
+        if len(self.success_feedback.replace(" ", "")) > 1000:
+            raise ValueError("success_feedback must not exceed 1000 characters")
+        if len(self.error_feedback.replace(" ", "")) > 1000:
+            raise ValueError("error_feedback must not exceed 1000 characters")
+
         self.headers = self.headers or {}
         self.payload = self.payload or {}