> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vijil.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Discover Vijil’s evaluation service

Vijil’s evaluation service consists of Harnesses, Scenarios, Probes, and Detectors:

<img src="https://mintcdn.com/vijil/t1_8aRtSIj494eFA/images/legacy/Harness-scenario-probe-detector.webp?fit=max&auto=format&n=t1_8aRtSIj494eFA&q=85&s=8a2fe79cb7be71512a91288f27743e36" alt="Vijil Evaluation components" width="837" height="505" data-path="images/legacy/Harness-scenario-probe-detector.webp" />

At the lowest level, [Detectors](/core-concepts/components/detector) scan model responses for undesirable features and register responses with those features as successful attacks on the model. For example, a Detector may be designed to look for fake Python packages.

At the next level, each [Probe](/core-concepts/components/probe) consists of one of more prompts designed to elicit certain undesirable responses. For example, a Probe could contain prompts to look for malware.

The next highest level consists of [Scenarios](/core-concepts/components/scenario), which are collections of Probes that have similar goals.

At the topmost level, [Harnesses](/core-concepts/components/harness) are collections of one or more Scenarios that you run to generate an overall trust score/report from. To run a Vijil evaluation, you have to select one of more Harnesses to include. The current Vijil Trust Score consists of three Harnesses: Security, Safety, and Reliability.

Learn more about trust score components:

<Columns cols={2}>
  <Card title="Harness" horizontal icon="shield" href="/core-concepts/components/harness" arrow="true">
    Learn more about Harnesses
  </Card>

  <Card title="Scenario" horizontal icon="boxes" href="/core-concepts/components/scenario" arrow="true">
    Learn more about Scenarios
  </Card>

  <Card title="Probe" horizontal icon="flask-conical" href="/core-concepts/components/probe" arrow="true">
    Learn more about Probes
  </Card>

  <Card title="Detector" horizontal icon="alarm-smoke" href="/core-concepts/components/detector" arrow="true">
    Learn more about Detectors
  </Card>

  <Card title="Guard" horizontal icon="brick-wall-shield" href="/core-concepts/components/guard" arrow="true">
    Learn more about Guard
  </Card>

  <Card title="Guardrail" horizontal icon="train-track" href="/core-concepts/components/guardrail" arrow="true">
    Learn more about Guardrail
  </Card>
</Columns>