# Environment and performance evidence

Canonical: https://fairleadhq.com/docs/recorder/environment-and-performance/

Updated: 2026-10-07
Publication state: published
Product version: Source verified — 52de40a

Agent summary: Read browser context and timing measurements alongside the recorded actions. Selected metrics are not a complete profiler; INP and CLS are not calculated.

## Prerequisites

- A recorded session open in the viewer

## Inputs

- Environment and timing evidence

## Outputs

- Context for a diagnostic handoff

## Limitations

- Selected metrics are not a complete profiler; INP and CLS are not calculated

## Permissions

- Access to the session

## Privacy

- Review captured content before sharing


Read browser context and timing measurements alongside the recorded actions.

Use environment and performance evidence to explain the conditions of an observation and choose the next diagnostic step.

## Inspect the environment

Open the [viewer](https://fairleadhq.com/docs/recorder/session-viewer/) and select **Environment**. Review available browser, device, page, and viewport context, plus **Language**, **Colour scheme**, **Connection**, and **Page load timing**. Add build, account role, test-data state, and any other conditions that Recorder cannot establish for your test.

Do not infer the deployed application build from the browser version. Record that reference separately in your test result.

## Read lifecycle and timing evidence

Open **Timeline** for FCP, LCP, long tasks, and other recorded performance events. Available lifecycle events can help explain page loading and navigation. Performance evidence includes First Contentful Paint (FCP), Largest Contentful Paint (LCP) observations, long tasks, and selected resource timings.

Long tasks use a 50 ms threshold. Resource evidence includes selected fetch/XHR, slow, cached, and render-blocking resources, subject to capture filtering. It is not an exhaustive resource inventory.

## Compare measurements carefully

FCP, LCP, and resource observers can supply buffered entries measured before Start. That does not mean Recorder captured the user actions that preceded Start. Check timestamps and the retained interval before relating measurements to your check.

Multiple LCP observations do not automatically give you a finalized page-level score. Browser support determines which entry types are available; absent metrics may be unavailable rather than zero.

## Investigate a delay

Compare available measurements with the action, [request timing](https://fairleadhq.com/docs/recorder/network/), and console errors. Keep network and device conditions stable across attempts, or document the differences.

Recorder does not calculate INP or CLS and does not provide a complete Core Web Vitals assessment. Use a browser profiler or dedicated measurement tool for deeper analysis and repeatable benchmarks. Follow [Investigate slow or unresponsive behavior](https://fairleadhq.com/docs/recorder/slow-or-unresponsive/) for the full workflow.

## Preserve the context

Include the relevant observed timings and environment in your handoff. The [download folder](https://fairleadhq.com/docs/recorder/bundle-contents/) is not an export of every viewer panel. Copy essential viewer-only context into your result; see [session and notes exports](https://fairleadhq.com/docs/recorder/bundle-contents/#session-summary-and-notes).