shadcn-detection

Detects which of the three shadcn/ui component bases a project uses: Base UI (`base`, default for new projects since July 2026), Radix (`radix`, fully supported) or React Aria (`aria`, added July 2026). Authoritative signal first (`shadcn info --json` -> `config.base`), then a 5-signal weighted scan: package.json dependencies, components.json's style prefix, source import patterns, data-attribute conventions (`data-state` vs `data-open` vs `data-entering`), and the lockfile-detected package manager.

Produces a Base UI / Radix / React Aria / Mixed (migration needed) / None (fresh setup) verdict that gates every downstream shadcn component or migration task.

shadcn Detection

Agent Workflow (MANDATORY)

Before detection, spawn agents in parallel, one Agent call each with a name:

1. fuse-ai-pilot:explore-codebase - Scan project structure
2. fuse-ai-pilot:research-expert - Verify latest primitive patterns

After: Use results to configure component workflow.

---

Overview

Feature	Description
CLI probe (authoritative)	{runner} shadcn@latest info --json -> .config.base = base | radix | aria (plus .config.style, .components, .links)
Package scan	Detect @base-ui/react, radix-ui / @radix-ui/*, react-aria-components
Config check	Analyze components.json style prefix (base-*, radix-*/new-york, aria-*)
Import analysis	Scan source for import patterns
Attribute scan	data-state= (Radix) vs data-open (Base UI) vs data-entering/data-placement (React Aria)
Package manager	Detect bun/npm/pnpm/yarn via lockfile

Base	Package	Style prefix	Composition	Docs
Base UI (default)	@base-ui/react	base-*	render prop	/docs/components/base/<name>
Radix	radix-ui (legacy @radix-ui/react-*)	radix-*, legacy new-york	asChild	/docs/components/radix/<name>
React Aria	react-aria-components	aria-*	Trigger wrapper (DialogTrigger > Button + Dialog), slot, onPress	/docs/components/aria/<name>

Known cross-base dependencies (NOT a mixed project): radix-* Combobox imports @base-ui/react (Radix has no Combobox); Questionnaire and MessageScroller import @shadcn/react on every base; every current component imports cn from the cn package.

---

Critical Rules

1. ALWAYS run detection before any component work
2. CHECK all 5 signals for maximum accuracy
3. HANDLE mixed state as migration case, never ignore
4. CACHE result for session duration, no re-detection needed
5. DETECT package manager via lockfile priority order

---

Architecture

project/
├── package.json            # Step 1: deps scan
├── components.json         # Step 2: style field
├── bun.lock|bun.lockb|pnpm-lock.yaml|yarn.lock|package-lock.json  # Step 5: PM
└── src/|components/|app/   # Step 3-4: imports + attrs

→ See detection-script.md for complete example

---

5-Step Detection Algorithm

Step 0: if components.json exists, {runner} shadcn@latest info --json gives the base directly; the weighted scan below confirms it and catches mixed projects.

Step	Signal	Weight
1	package.json deps (@base-ui/react, radix-ui / @radix-ui/*, react-aria-components)	40%
2	components.json style prefix (base-*, radix-*/new-york, aria-*)	20%
3	Import patterns in source files	25%
4	Data attributes (data-state= / data-open / data-entering)	15%
5	Package manager (lockfile → bunx/npx/pnpm dlx/yarn dlx)	-

---

Decision Table

Each base gets its own score (0-100).

Scores	Result	Action
Only Base UI >50	Base UI	Use Base UI patterns (render)
Only Radix >50	Radix	Use Radix patterns (asChild)
Only React Aria >50	React Aria	Use React Aria patterns (trigger wrapper, onPress)
Two or more >0 (after discounting the known cross-base deps above)	Mixed	Migration needed
All 0	None	Fresh setup: init defaults to Base UI; pass -b radix or -b aria to choose

---

Best Practices

DO

• Run detection BEFORE any component work
• Check all 5 signals for accuracy
• Handle "mixed" state as migration case

DON'T

• Assume Radix (or Base UI, the new default) without checking
• Skip components.json analysis
• Ignore data-attribute signals
• Count @base-ui/react from a Radix-style Combobox as a mixed project

---

Reference Guide

Concepts

Topic	Reference	When to Consult
Radix Patterns	radix-patterns.md	Identifying Radix UI signals
Base UI Patterns	baseui-patterns.md	Identifying Base UI signals
Algorithm	detection-algorithm.md	Understanding scoring logic, React Aria signals

Templates

Template	When to Use
detection-script.md	Running detection on a project