MCP Agent Skill — mui
MUI Breaking Changes Skill for MCP Agent
What an agent writing React against MUI gets wrong from training-data drift — Material UI v5→v9 and MUI X v8 breaking changes, the version-pinned docs trap, Grid/slots/theming API deltas, licensing tiers, and TypeScript augmentation moves. Registry-verified.
sidebutton install mui MUI Breaking Changes
MUI is where model training data most likely betrays a React agent: four majors' worth of renamed
and removed APIs sit exactly where a model's v5-era reflexes point (Grid item xs,
componentsProps, makeStyles, InputProps), and the official docs at mui.com silently serve
the newest major. This pack maps the breakage so an agent's first pass compiles against the major
the codebase actually runs.
Everything registry-verifiable here was checked against registry.npmjs.org or probed on
unpkg.com on 2026-08-08 — release dates, peer ranges, which import paths ship at which major.
Where a decision hangs on a number, re-resolve it rather than trusting this text.
Module Inventory
| Module | Covers | _skill.md |
|---|---|---|
| version-delta | The "no Material UI v8" fact, per-major breaking changes v5→v9, the version-pinned docs trap, packages/styling/theming/slots/Grid deltas, MUI X v8 and its licensing tiers, TypeScript augmentation moves | 0.85 |
Authoring Rules
- Registry over memory. Every version, date, peer range and import-path claim cites the npm registry or an unpkg probe, with the date it was checked.
- State the major for every API. The column that matters is introduced, not removed — an API that post-dates the codebase's major is as wrong as a removed one.
- No application-specific claims. Which major a given product runs belongs in that consumer's own domain pack, never here.