transitions

A shared motion system for Next.js 16 applications using the App Router, a framework feature for handling pages and routes. It provides named animation settings and reusable interactions instead of separate timings and effects in each component.

In plain words
What is it for?
Adding or auditing entrance and exit effects, hover feedback, modals, dropdowns, toasts, accordions, layout changes, and transitions between pages.
Why use it?
It keeps animations consistent across the app and avoids scattered, hard-to-maintain motion values.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/lukedj78/dev-flow/transitions
Any agent
npx skills add lukedj78/dev-flow --skill transitions
Clone the repo
git clone --depth 1 https://github.com/lukedj78/dev-flow

Made for: Claude Code, Codex.

Per session 221 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,115 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00221 $0.03115
Opus 5 $0.00111 $0.01558
Sonnet 5 $0.00044 $0.00623
Haiku 4.5 $0.00022 $0.00312

Measured 2d ago against content hash 78f38f69ce44, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

transitions scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/scan_motion.py, scripts/test_scan_motion.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

transitions/SKILL.md · 142 lines

How it starts

The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.

transitions — one tokenized motion system for a Next.js 16 app

This skill governs how a web app moves. Like state-discipline for state and forms for forms, it routes every animation through one shared, token-driven system so the product has a single, consistent motion feel — instead of scattered duration-[237ms] magic numbers and hand-tuned cubic-beziers that drift page to page.

Inspired by transitions.dev (Jakub Antalík) — a curated library that teaches agents about product motion. This is our own take: token-driven, wired to the DESIGN.md contract and our Next.js 16 + Motion + tw-animate-css stack. Not a fork, not an install of their package — we credit the idea and build our own.

When this skill applies

  • The user says "add a transition / animation", "animate this", "aggiungi una transizione", "make the modal open nicely", "stagger these cards", "page transition between routes".
  • You're about to write an inline transition: / animate={{…}} / @keyframes / a Tailwind duration-[Xms] arbitrary value.
  • The user asks to audit a codebase for ad-hoc motion.
  • A component needs entrance/exit, hover, feedback, layout, or route motion.

If the effect genuinely needs JS physics (spring, layout/shared-element, drag/gesture, scroll choreography) and the Motion runtime isn't wired, this skill routes to module-add motion first, then applies the tokenized pattern on top.

Contract

Follows the dev-flow contract — see references/contracts.md. Key facts:

  • Reads meta.json#stack.framework, stack.nextjs_version, stack.motion. For monorepo, reads stack.monorepo.web.* and operates in apps/web/.
  • Refuses if stack.framework ∉ {"next", "monorepo"} or stack.nextjs_version != "16". Principles transfer to other React setups but the View-Transitions/RSC rungs don't — refuse rather than mis-apply.
  • Records meta.json#stack.motion (see block below) + appends history per run.
  • Does not bump phase. Horizontal capability — invoke any time.

Read the full file on GitHub · 142 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 142 lines · 221 tokens per session scan A 78f38f69ce44

Subscribe to this mod's changes

transitions is a skill published in the GitHub repository lukedj78/dev-flow (5 stars, last pushed 4d ago), licensed MIT. It adds 221 tokens to every session and 3,115 once invoked, about $0.0011 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.