verify

verify - visual verification as Definition of Done

Visual verification is the credo Definition-of-Done gate for anything with a runtime surface. If a change renders something, updates something on screen, or reacts to a user action, it is not done until that behavior has been observed - either by the user in a real browser, or by a reliable automated Playwright check that drives the real build. This skill is the DoD gate that ui: true items require.

Task backend. If the task backend is gsd (.credo/config: task_backend, or the CREDO_TASK_BACKEND env override), the credo item lifecycle is inactive, so there is no credo item to move to done - GSD owns task tracking. The verification method here still applies as a general "prove it renders" tool; just do not gate a credo item with it in that mode.

What does NOT count as verification

None of these are a substitute for visual proof:

• pytest / unit tests / integration tests passing
• node --check, a type-check, a lint pass, or a successful build
• "the file is served" / "the server returned 200"
• a subagent code-review or a static read of the source

They can all be green while the surface renders broken, never updates, or ignores the user. Verification means the rendered surface was exercised and observed.

Two accepted forms of proof

1. Browser verification by the user - the user opens the real surface and confirms it.
2. A reliable Playwright check - drives the actual build in a real browser, measures computed layout, exercises the real interaction, and captures evidence.

Anything else is "wired-but-behavior-unverified", not "exercised".

Scope of a real verification

• Rendered layout measured via computed layout - read getBoundingClientRect() (and computed styles where relevant), do not rely on a screenshot alone. A screenshot is evidence, not the measurement; a plausible-looking screenshot can still hide a zero-height or off-canvas element that the box metrics expose.
• Live update without a full reload where that is required - if the surface is meant to update in place (no F5), verify it actually does, by triggering the update and observing the change without reloading.
• Real interaction - click, type, submit, hover as a user would; verify the observable result, not just that a handler exists.
• Hard reload after a rebuild - after rebuilding, force a hard reload (bypass cache) before verifying, so you are testing the new build and not a stale cached bundle.

Viewports

Verify at each configured viewport width. The universal defaults are 320, 768 and 1440 px, but read them from config as the source of truth - they may be overridden per project:

"${CLAUDE_PLUGIN_ROOT}/scripts/credo-config.sh" get verify.viewports

(Config key: verify.viewports.) Resize to each width, then measure and capture at that width.

Run it in a subagent singleton browser

Run the Playwright verification inside a subagent that owns a single browser instance (a singleton), rather than spawning browsers in the main agent or opening several in parallel. One browser, driven step by step, keeps the run deterministic and keeps browser noise out of the main context. See the credo orchestration skill for how to delegate and monitor such a subagent without flooding the main context.

Evidence: screenshots

Capture one screenshot per viewport and save it to .credo/screenshots/ using this exact naming rule:

<task-or-feature>-<viewport>-<YYYY-MM-DD>.png

Example: login-form-320-2026-07-04.png. <task-or-feature> is a short slug (an item slug or feature name), <viewport> is the width in px, and the date is the day of the verification. The .credo/ directory is git-excluded by design, so screenshots are local evidence, not committed artifacts.

Definition-of-Done gate

A change with a runtime surface is done only when its observable success criteria are exercised (or confirmed by the user for human-only criteria). For items marked ui: true, a passing visual verification at every configured viewport - measured layout, real interaction, live update where required, hard reload after rebuild, and saved screenshots - is mandatory before the item may move to done. If verification surfaces a defect, the item is not done: it goes back to clarification with a note on what was missed, per the credo item model. Never downgrade or self-approve this gate.