argent-screenshot-diff

1. Role

Use screenshot-diff as supporting visual evidence for UI QA and visual regression checks. It highlights pixel-visible change or stability; it does not replace visual inspection, accessibility/component-tree state, frame/attribute checks, logs, network evidence, or app behavior.

Do not use screenshot diffing for tap-coordinate discovery. Use describe, debugger-component-tree, or native-describe-screen to find targets first.

2. When To Use

Use screenshot-diff when pixel comparison can answer the verification question:

• Required for explicit "UI regression test", "visual regression test", "screenshot diff", "compare screenshots", or "before/after visual comparison" requests, unless stable comparable screenshots cannot be produced.
• Good fit when the affected screen has stable before/after states and the expected result is pixel-visible: layout, position, size, spacing, color, typography, image/icon rendering, clipping, overflow, or text rendering.
• Good fit when the risk is unintended visual regression outside the exact element changed.
• Poor fit when the result is better verified structurally: state changes, navigation existence, accessibility tree contents, console/network behavior, or unit tests.
• Poor fit when dynamic content, unpausable animation, timestamps, ads, random data, or missing baseline/current screenshots would make the comparison noisy or meaningless.

3. Capture Rules

Use normal downscaled screenshot calls for UI context and state checks. Use full-resolution screenshots only when saving baseline/current PNG files for visual regression comparison. Suppress the image block so the full-size PNG is not loaded into context: