Transition Consistency
Decide once what animates, for how long, and when motion is left out entirely.
What it adds
A single set of rules governing which properties may be transitioned across the app, and which interactions deliberately have no motion at all.
What your agent is told to do
5
What your agent is told to do
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Audit the app for every transition currently in place and record what it animates. Anything transitioning a property that forces the browser to recompute layout is the first thing to replace.
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Restrict transitions to properties that can be composited — opacity and transforms — and express size and position changes that way rather than animating width, height, or offsets directly.
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Write down the interactions that must never animate: value updates in a table the user is scanning, error messages appearing, and anything that would delay the confirmation of an action.
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Make motion decorative rather than load-bearing. The state change lands immediately and the animation describes it afterwards, so a user on reduced motion or a slow device sees the same result at the same moment.
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Do not implement this by adding a blanket transition to every element. A universal rule catches things it was never meant to, and produces elements that visibly drift when they should appear instantly.
Edge cases it handles
7
Edge cases it handles
7- Transitions on properties that trigger layout or paint on every frame will stutter on modest hardware and on long lists; move them to transforms and opacity or drop them.
- Motion must never sit between the user and the result of their action — a button that waits for an animation to finish before committing feels broken regardless of how good the animation is.
- Rapid toggling must be handled explicitly. Clicking a disclosure five times quickly should end in the correct final state, with each transition picking up from wherever the last one reached.
- When the user has asked for reduced motion the app must honour it at the level of the whole system, and the layout must be identical with motion on and off.
- Durations and curves themselves are owned by Motion Token System; this entry decides which properties are eligible and where motion is omitted, and should reference those tokens rather than defining new values.
- Transitions inside a virtualised or paginated list must not fire when rows are recycled, or scrolling produces a wall of animation.
- An element that is animating must still be clickable and focusable throughout, not inert until the motion settles.
Definition of done
8
Definition of done
8- Transitions are limited to compositable properties across the whole app.
- No interaction waits on an animation before its result is committed.
- Rapid repeated toggling always settles in the correct final state.
- Reduced-motion preferences are honoured system-wide, with identical layout in both modes.
- Timing values come from the shared motion tokens rather than being defined locally.
- Recycled rows in long lists do not replay entrance transitions.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Semantic Color Tokens
Semantic Color Tokens
Name colours by the job they do, so changing a theme is one edit rather than a sweep.
What it does
A vocabulary of role-named colour tokens — surface, text, border, accent, danger, success — that components reference instead of literal values.
How it works
- 1 Inventory every literal colour value in the codebase and group them by the job they are doing rather than by the shade they happen to be. Two different greys used as card backgrounds are one role; the same grey used as a background and as a border is two.
- 2 Define the role names once and map each role to a value per theme. A role may resolve to a light grey in one theme and a near-black in another; what must not change is which components reference it.
- 3 Stop shared components accepting raw colour values. A primitive that takes a hex string as a prop guarantees that some product screen will hardcode a colour the themes never learn about.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/semantic-color-tokens
Motion Token System
Motion Token System
Give the app one shared vocabulary of durations and easing curves instead of ad hoc numbers.
What it does
A named set of durations and easing curves, each tied to a category of motion, replacing the timing values scattered through the app's components.
How it works
- 1 Inventory every duration and easing value currently written into the app and group them by what they do: something entering, something leaving, something being emphasised, and something changing size or position.
- 2 Name a small set of durations — roughly instant, quick, standard, and deliberate — and a small set of curves, then map each motion category to a pairing. Four or five of each is enough for an entire product.
- 3 Give entrances and exits different treatment. Something arriving should decelerate into place; something leaving should accelerate away and take less time, because nobody wants to wait for a dismissal.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/motion-token-system
Container Width System
Container Width System
Give pages a few defined widths instead of a different max-width on every screen.
What it does
A small set of named page widths — narrow, standard, wide, and full-bleed — applied consistently across the app.
How it works
- 1 Measure the max-width used on every top-level page and group them. Settings forms, prose, dashboards, and data tables usually want three or four distinct widths between them, not the eleven the codebase currently has.
- 2 Pick each width from the content it holds. A reading column is bounded by comfortable line length, a settings form by field width, and a table by the number of columns that must stay visible.
- 3 Make horizontal page padding part of the container rather than something each page adds, so content never touches the viewport edge on a narrow screen even at the widest setting.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/container-width-system
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.