trulens-core

library2.8.0pypypiunverified

TruLens is a library for systematically tracking and evaluating LLM-based applications. It provides instrumentation, feedback functions, and a dashboard for monitoring and improving LLM app performance. Current version: 2.8.0, with monthly releases.

llm-agents ai-ml observability

pip install trulens-core

github ↗package ↗homepage ↗docs ↗

INSTALL

IMPORT

SIG · TRULENS-CORE

trulens-core

llm-agentspythonv2.8.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Initialize TruLens session and define a feedback function.

from trulens.core import TruSession from trulens.feedback import Feedback from trulens.providers.openai import OpenAI session = TruSession() session.reset_database() provider = OpenAI(model_engine="gpt-4o-mini", api_key=os.environ.get('OPENAI_API_KEY', '')) f_groundedness = Feedback(provider.groundedness_measure_with_cot_reasons, name="Groundedness") print("Feedback defined.") # See docs for full quickstart: https://www.trulens.org/

tru --version

Debug

Known issues

breakingIn version 2.7.0, the `Feedback` class and `MetricConfig` were replaced by the unified `Metric` class. Old code using `Feedback(...).on_output().on_input()` will break.

fix

Migrate to `Metric` class with explicit selectors dictionary. See migration guide: https://www.trulens.org/trulens/api/metrics/

affects: <2.7.0

deprecated`run_dashboard_sis` is deprecated as of 2.7.2.

fix

Use `TruSession().run_dashboard()` instead.

affects: >=2.7.2

gotchaFeedback functions require an LLM provider to be initialized with a valid API key. If the key is missing or invalid, they will fail silently or raise cryptic errors.

fix

Always check that the provider is correctly instantiated with `api_key` or `base_url` and test with a known good key.

affects: all

gotcha`TruSession` is the new session class starting from 2.0, replacing the old `Tru` class. Importing `Tru` directly will raise ImportError.

fix

Use `from trulens.core import TruSession` instead of `from trulens import Tru`.

affects: >=2.0.0

Errors

Common errors & fixes

ImportError: cannot import name 'Tru' from 'trulens'

The old `Tru` class was removed in favor of `TruSession` starting from v2.0.

fix

Use `from trulens.core import TruSession` and replace `Tru()` with `TruSession()`.

AttributeError: 'OpenAI' object has no attribute 'groundedness_measure_with_cot_reasons'

Feedback function names changed between versions. The API is version-specific.

fix

Check the correct method name in the provider's documentation. For OpenAI, use `provider.groundedness_measure_with_cot_reasons` (available in 2.x).

ModuleNotFoundError: No module named 'trulens_eval'

The old `trulens_eval` package was split into `trulens-core` and other subpackages starting from v2.0.

fix

Install `trulens-core` and use `from trulens.core import ...` instead.

Upgrade

Version history

2.8.0latest on PyPI · released Apr 30, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

33 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/truera/trulens ↗

packagehttps://pypi.org/project/trulens-core/ ↗

homepagehttps://trulens.org/ ↗

docshttps://trulens.org/getting_started/ ↗