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

# Core concepts

> The vocabulary you'll see everywhere in Percio

Before you go deeper, here's the vocabulary the rest of the docs uses.

## Test

A single usability evaluation of a URL. A test has a **scenario**, a **persona**, and produces a **result**. Every test run consumes credits — see [Credits](/billing/credits).

## Scenario

The task you want a persona to attempt. Good scenarios describe *what the user is trying to accomplish*, not step-by-step instructions. Examples:

* "Find a pair of running shoes under \$120 and add them to the cart"
* "Sign up for an account and post your first comment"
* "Cancel an existing subscription"

Bad scenarios are too vague ("explore the site") or too prescriptive ("click button X, then Y, then Z"). See [Writing good scenarios](/tests/writing-scenarios).

## Persona

The lens Percio uses to evaluate your product. A persona has an occupation, a device context, a tech expertise level, focus areas, pain points, behavioral traits, priority Nielsen heuristics, and a full system prompt that governs how it interprets what it sees.

Personas in Percio are either **created during onboarding**, **created by you** on the `/personas` page, or generated via the **Agent's MCP tools**. There are no generic built-in personas — every persona is specific to your product.

See [Personas overview](/personas/overview).

## Flow

The sequence of steps the browser actually took during a test — click here, type there, scroll down, navigate away. The flow is what the persona evaluates after the run is complete.

## Step

One action inside a flow. Each step has: a screenshot captured before the action, the agent's reasoning, and the action it took (click, type, select, scroll, wait, navigate, complete, or abandon).

Tests cap at **50 steps** by default in the agent (you can adjust with `--max-steps`). Tests can end early if the agent hits 3 consecutive failures, gets stuck below 50% progress, or decides the task is done.

## Issue

A specific usability problem a persona found. Each issue has:

* **Severity** (critical / high / medium / low)
* **Nielsen heuristic** it violates
* **What's happening** — the observed problem
* **Why it matters** — the user impact
* **Who it affects most** — when the issue hits some users harder than others
* **Recommendation** — a concrete fix

After a test, you can mark each issue **Confirmed**, **False positive**, or **Dismissed**.

## Heuristic

A usability principle from Jakob Nielsen's 10 heuristics (visibility of system status, match between system and real world, user control, consistency, error prevention, recognition over recall, flexibility, aesthetic and minimalist design, help users recover from errors, help and documentation). Every issue ties to one so you know *why* it's a problem, not just *that* it's a problem.

## Credit

The unit that meters test runs. Running a test costs credits — creating a persona in the web app does not. Your plan (Indie or Pro) determines how many credits you get per billing cycle. If you run out, new test runs are blocked until the next cycle or an upgrade. See [Credits](/billing/credits).

## Execution

A single test run identified by an `executionId`. The live test page lives at `/test-running/[executionId]` and the final report lives at `/results/[executionId]`. You can share a results URL with teammates on your account.

## Report retention

Results are kept for the lifetime of your plan window — **90 days on Indie**, **365 days on Pro**. After that they're deleted. If long-term archiving matters to you, export what you need before it ages out.

## What's next

* [Creating a test](/tests/overview)
* [Personas overview](/personas/overview)
* [Reading results](/results/overview)