Collect User Feedback

Capturing user feedback is critical for understanding the real-world quality of your GenAI application. MLflow's Feedback API provides a structured, standardized approach to collecting, storing, and analyzing user feedback directly within your traces.

Adding Feedback with MLflow UI

Adding Feedback with API

To annotate traces with feedback programmatically, use the mlflow.log_feedback() API.

python
import mlflow
from mlflow.entities import AssessmentSource, AssessmentSourceType

mlflow.log_feedback(
    trace_id="<your trace id>",
    name="user_satisfaction",
    value=True,
    rationale="User indicated response was helpful",
    source=AssessmentSource(
        source_type=AssessmentSourceType.HUMAN, source_id="user_123"
    ),
)

If you have a Feedback object already (e.g., a response from LLM-as-a-Judge), you can log it directly using the mlflow.log_assessment() API. This is equivalent to using the

mlflow.log_feedback() API with unpacked fields.

python
import mlflow
from mlflow.genai.judges import make_judge
from typing import Literal

coherence_judge = make_judge(
    name="coherence",
    instructions=(
        "Evaluate if the response is coherent, maintaining a constant tone "
        "and following a clear flow of thoughts/concepts"
        "Trace: {{ trace }}\n"
    ),
    feedback_value_type=Literal["coherent", "somewhat coherent", "incoherent"],
    model="anthropic:/claude-opus-4-1-20250805",
)

trace = mlflow.get_trace("<your trace id>")
feedback = coherence_judge(trace=trace)

mlflow.log_assessment(trace_id="<your trace id>", assessment=feedback)
# Equivalent to log_feedback(trace_id="<trace_id>", name=feedback.name, value=feedback.value, ...)"

Supported Value Types

MLflow feedback supports various formats to match your application's needs:

Feedback Type	Description	Example Use Cases
Boolean	Simple `True`/`False` feedback	Thumbs up/down, correct/incorrect
Numeric	Integer or float ratings	1-5 star ratings, confidence scores
Text	Free-form text feedback	Detailed quality breakdowns

Supported Feedback Sources

The source field of the feedback provides information about where the feedback came from.

Source Type	Description	Example Use Cases
HUMAN	Human feedback	User thumbs up/down, correct/incorrect
LLM_JUDGE	LLM-based feedback	Score traces with an LLM-based judge
CODE	Programmatic feedback	Score traces with a programmatic checker