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

# Verification

> How Twill validates implementations

After implementation, Twill verifies the changes meet requirements and pass quality checks.

## Verification Steps

* **Build check**: Ensures the project builds successfully
* **Test execution**: Runs your test suite
* **Lint validation**: Checks code style and standards
* **UI verification**: Browses flows and captures screenshots or screen recordings when the change needs visual proof

<Frame>
  <img src="https://mintcdn.com/twill/kGLDvgTksG_NxLEU/images/agent-logs-showing-screenshot.png?fit=max&auto=format&n=kGLDvgTksG_NxLEU&q=85&s=b95a9353619fcaa7385f319b2801cc7b" alt="Agent logs showing verification steps and screenshots" width="2880" height="2240" data-path="images/agent-logs-showing-screenshot.png" />
</Frame>

## Proof of Work

Twill attaches proof artifacts to pull requests and task conversations so
reviewers can verify the implementation works. Depending on the task, that can
include test results, logs, screenshots, live previews, and browser recordings.

For simple UI checks, Twill may attach screenshots. For multi-step browser
flows, Twill may attach a screen recording instead. Recorded `.mp4` and `.webm`
artifacts render inline in Twill task conversations.

<Frame>
  <img src="https://mintcdn.com/twill/lDT9bWmueiookMD7/images/pr-with-proof.png?fit=max&auto=format&n=lDT9bWmueiookMD7&q=85&s=fda552bacd8067c277ce28da691c0560" alt="Pull request with proof of work attached" width="1862" height="1728" data-path="images/pr-with-proof.png" />
</Frame>

## Auto-Fix

When verification fails, the agent can automatically attempt fixes. See [CI Fixes](/agent/auto-fix-ci) for details.