TruLens is an open-source system for tracing and evaluating LLM applications and AI agents. It records each step's inputs, outputs, latency, tokens, and cost, then uses evaluations to find failures and compare application versions.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add truera/trulens --skill trulens-dataset-curationgit clone --depth 1 https://github.com/truera/trulensWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/truera/trulens/trulens-dataset-curation)<a href="https://agentmods.dev/skills/truera/trulens/trulens-dataset-curation"><img src="https://agentmods.dev/badge/skills/truera/trulens/trulens-dataset-curation/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/truera/trulens/trulens-dataset-curation"><img src="https://agentmods.dev/badge/skills/truera/trulens/trulens-dataset-curation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00019 | $0.01310 |
| Opus 5 | $0.00010 | $0.00655 |
| Sonnet 5 | $0.00004 | $0.00262 |
| Haiku 4.5 | $0.00002 | $0.00131 |
Grade A, and why
trulens-dataset-curation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 218 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TruLens Dataset Curation
Create evaluation datasets with ground truth to measure your LLM app's performance.
Overview
Ground truth datasets allow you to:
- Compare LLM outputs against expected responses
- Evaluate retrieval quality against expected chunks
- Track performance across app versions
- Share evaluation data across your team
Prerequisites
pip install trulens pandas
Instructions
Step 1: Initialize TruSession
from trulens.core import TruSession
session = TruSession()
Step 2: Create Ground Truth Data
Structure your data as a pandas DataFrame with these columns:
| Column | Required | Description |
|---|---|---|
query |
Yes | The input query/question |
query_id |
No | Unique identifier for the query |
expected_response |
No | The expected/ideal response |
expected_chunks |
No | Expected retrieved contexts (list or string) |
import pandas as pd
data = {
"query": [
"What is TruLens?",
"How do I instrument a LangChain app?",
"What is the RAG triad?",
],
"query_id": ["q1", "q2", "q3"],
"expected_response": [
"TruLens is an open source library for evaluating and tracing AI agents.",
"Use TruChain to wrap your LangChain app for automatic instrumentation.",
"The RAG triad consists of context relevance, groundedness, and answer relevance.",
],
"expected_chunks": [
[
"TruLens is an open source library for evaluating and tracing AI agents, including RAG systems."
],
[
"from trulens.apps.langchain import TruChain",
"tru_recorder = TruChain(chain, app_name='MyApp')",
],
[
"Context relevance evaluates retrieved chunks",
"Groundedness checks if response is supported by context",
"Answer relevance measures if the response answers the question",
],
],
}
ground_truth_df = pd.DataFrame(data)
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 12d ago First seen · 218 lines · 19 tokens per session scan A 09a069a5ac64
trulens-dataset-curation is a skill published in the GitHub repository truera/trulens (3,547 stars, last pushed today), licensed MIT. It adds 19 tokens to every session and 1,310 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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