truera/trulens: TruLens 2.7.0

New Unified Metric API

We're introducing the Metric class as the new primary API for evaluation metrics in TruLens. This unified interface replaces both Feedback and MetricConfig with a cleaner, more explicit design.

Why This Matters

• Clearer, more readable code: Replace chained .on_*() methods with an explicit selectors={} dictionary—no more guessing which argument maps to which selector
• Single unified class: No need to choose between Feedback and MetricConfig for different use cases
• Better OTel integration: Native support for selecting data from OpenTelemetry spans

As a bonus, the same Metric code is now portable to Snowflake environments without modification.

Quick Example

Before (Feedback):

f_groundedness = (
    Feedback(provider.groundedness_measure_with_cot_reasons, name="Groundedness")
    .on_context(collect_list=True)
    .on_output()
)

After (Metric):

f_groundedness = Metric(
    implementation=provider.groundedness_measure_with_cot_reasons,
    name="Groundedness",
    selectors={
        "source": Selector.select_context(collect_list=True),
        "statement": Selector.select_record_output(),
    },
)

The selectors dict makes it explicit which function parameter receives which data.

Migrating from MetricConfig

Before (MetricConfig):

from trulens.core.feedback.custom_metric import MetricConfig

config = MetricConfig(
    metric_name="word_count",
    metric_implementation=lambda text: len(text.split()),
    selectors={"text": Selector.select_record_output()},
)
feedback = config.create_feedback_definition()

After (Metric):

from trulens.core import Metric, Selector

metric = Metric(
    name="word_count",
    implementation=lambda text: len(text.split()),
    selectors={"text": Selector.select_record_output()},
)

Backward Compatibility

The existing Feedback class continues to work with a deprecation warning, giving you time to migrate:

# Still works, but deprecated
from trulens.core import Feedback
f = Feedback(provider.relevance).on_input().on_output()

See the migration guide for detailed instructions on updating your code.

Bug Fixes

• fix: correct typo 'occurences' to 'occurrences' by @thecaptain789 in https://github.com/truera/trulens/pull/2349
• Drop pkg_resources dependency from trulens-core by @debu-sinha in https://github.com/truera/trulens/pull/2351
• fix: add circular-reference-safe repr to SerialModel (#1862) by @sfc-gh-jreini in https://github.com/truera/trulens/pull/2356
• Forward litellm routing params (api_base, api_key, etc.) to completion calls by @sfc-gh-jreini in https://github.com/truera/trulens/pull/2357
• fix: guard against None model_name in OpenAI endpoint (#1700) by @sfc-gh-jreini in https://github.com/truera/trulens/pull/2358

Docs

• New Example and Docs Updates for usage in MLFlow by @sfc-gh-jreini in https://github.com/truera/trulens/pull/2359

New Contributors

• @thecaptain789 made their first contribution in https://github.com/truera/trulens/pull/2349

Full Changelog: https://github.com/truera/trulens/compare/trulens-2.6.0...trulens-2.7.0