diff --git a/src/models/requests.py b/src/models/requests.py
index 5639493b..9db27d4d 100644
--- a/src/models/requests.py
+++ b/src/models/requests.py
@@ -2,7 +2,7 @@
 
 from typing import Optional, Self
 
-from pydantic import BaseModel, model_validator, field_validator
+from pydantic import BaseModel, model_validator, field_validator, Field
 from llama_stack_client.types.agents.turn_create_params import Document
 
 from utils import suid
@@ -159,7 +159,13 @@ class FeedbackRequest(BaseModel):
     user_question: str
     llm_response: str
     sentiment: Optional[int] = None
-    user_feedback: Optional[str] = None
+    # Optional user feedback limited to 1–4096 characters to prevent abuse.
+    user_feedback: Optional[str] = Field(
+        default=None,
+        max_length=4096,
+        description="Feedback on the LLM response.",
+        examples=["I'm not satisfied with the response because it is too vague."],
+    )
 
     # provides examples for /docs endpoint
     model_config = {
diff --git a/tests/unit/models/test_requests.py b/tests/unit/models/test_requests.py
index 7da1cc3b..3f97329b 100644
--- a/tests/unit/models/test_requests.py
+++ b/tests/unit/models/test_requests.py
@@ -1,5 +1,5 @@
 import pytest
-
+from pydantic import ValidationError
 from models.requests import QueryRequest, Attachment, FeedbackRequest
 
 
@@ -176,3 +176,15 @@ def test_check_sentiment_or_user_feedback(self) -> None:
                 sentiment=None,
                 user_feedback=None,
             )
+
+    def test_feedback_too_long(self) -> None:
+        """Test that user feedback is limited to 4096 characters."""
+        with pytest.raises(
+            ValidationError, match="should have at most 4096 characters"
+        ):
+            FeedbackRequest(
+                conversation_id="12345678-abcd-0000-0123-456789abcdef",
+                user_question="What is this?",
+                llm_response="Some response",
+                user_feedback="a" * 4097,
+            )