Preview and rendering troubleshooting

First decide whether the mismatch exists in authored data, the editor canvas, runtime Preview, generated output, or the final consumer. These surfaces answer different questions and can fail independently.

Preview is unavailable

Confirm the file kind. Pages and visual Components have runtime Preview; Mockups do not. Review a Mockup on the editor canvas or request an MCP screenshot with view: "editor".

For host-assisted MCP Preview, also resolve MCP connection.

Preview shows an old or incomplete result

1. Read the current file/element data to confirm whether the intended change exists.

2. Review any visible dependency Update prompt deliberately.

3. Reset or reopen the Preview session when clean runtime state is required.

4. Repeat the smallest case with the exact screen, variant, theme, test case, and identity.

Do not rewrite good project data merely because one render host may be stale.

The responsive result is wrong

Test just below, at, and just above the intended width. Responsive screens share one hierarchy and change style values; a structural difference must be modeled as compatible visibility/layout behavior, not as an assumed separate tree.

Compare authored values, computed style, and geometry. Remember that generated responsive output uses container-query behavior, so the consumer's container matters.

An interaction does nothing

Check the actual trigger, condition branches, value source, target, and Preview state. For typing or keyboard operations, focus the intended Preview element first. Inspect interpreter/action history and generated logic when the UI state alone does not explain the result.

The current Preview handling of multiple branches is not a safe substitute for testing generated semantics; same-branch conditions can behave as AND in Preview while exported logic honors the stored operator.

A timeline looks different after export

Verify the timeline trigger, target scope, duration, easing, resting state, and responsive context in both Preview and the real consumer. Per-screen target overrides are currently not exported as breakpoint-specific target sets, and shader animation is currently static in generated output.

A screenshot looks correct—is the task done?

No. A screenshot proves one visual moment. Test focus, interaction, responsive boundaries, data states, animation, diagnostics, and the destination build as appropriate.