# Behavior traces — shadcn-ui/ui

> Canonical page: https://codevetter.com/unpack/ui/behavior-traces

# Behavior traces — shadcn-ui/ui

Scanned commit 98a1fe67b439324ddc857f47fbdce056600a4329 (2026-09-21). Generated by codevetter codevetter 1.12.0 on 2026-09-22.

Traced flows: CLI startup, `init` (including empty-project scaffold and registry:base merge), `add` (including missing-config fallback into runInit and dry-run), the install pipeline inside addComponents, the registry fetch pipeline, `build`, the MCP server, and the website's registry:build production path.
- Startup: node dist/index.js → imports 13 command modules → new Command().name('shadcn').version(pkg.version) → addCommand(init, apply, add, diff, docs, view, search, migrate, eject, info, build, mcp, preset, registry) → program.parse() → per-command .action handler; SIGINT/SIGTERM exit 0. — [packages/shadcn/src/index.ts#L1-52](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/index.ts#L1-L52)
- init flow: initOptionsSchema.parse → validate --template/--preset → monorepo-root guard → existing components.json overwrite prompt + optional --reinstall component enumeration → template/base/preset prompts → resolveInitUrl → loadEnvFiles → createFileBackup(components.json) → resolveRegistryBaseConfig(first URL) → runInit. — [packages/shadcn/src/commands/init.ts#L163-601](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/commands/init.ts#L163-L601) [packages/shadcn/src/utils/file-helper.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/utils/file-helper.ts)
- runInit: resolveTemplate(template,{monorepo}) → (skip preflight for monorepo template init) preFlightInit → on MISSING_DIR_OR_EMPTY_PROJECT createProject() → getProjectConfig → template.init(...) early-return for template-managed init, else promptForMinimalConfig/promptForConfig → confirm write → ensureRegistriesInConfig → write components.json → getWorkspaceConfig propagation → explorer.clearCaches() → addComponents(['index', url..., 'button']) → templatePostInit. — [packages/shadcn/src/commands/init.ts#L603-842](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/commands/init.ts#L603-L842) [packages/shadcn/src/preflights/preflight-init.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/preflights/preflight-init.ts) [packages/shadcn/src/utils/create-project.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/utils/create-project.ts)
- add flow: addOptionsSchema.parse → loadEnvFiles → getConfig (createConfig fallback) → ensureRegistriesInConfig → getProjectInfo → warnForDeprecatedComponents → getRegistryItems([first]) to learn item type (theme/style/base skip index, universal items short-circuit to addComponents) → promptForRegistryComponents if none → preFlightAdd → on MISSING_CONFIG prompt then runInit(...) → on MISSING_DIR createProject+runInit → dryRunComponents+formatDryRunResult if --dry-run/--diff/--view → addComponents → updateAppIndex for v0 /chat/b/ blocks. — [packages/shadcn/src/commands/add.ts#L67-328](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/commands/add.ts#L67-L328) [packages/shadcn/src/preflights/preflight-add.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/preflights/preflight-add.ts) [packages/shadcn/src/utils/update-app-index.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/utils/update-app-index.ts)
- Install internals: addComponents → getWorkspaceConfig → addWorkspaceComponents (files grouped by TargetAliasKey ui/hooks/lib, per-target updateFiles) or addProjectComponents → resolveAndValidateRegistryTree → validateFilesTarget → massageTreeForFonts → getSupportedFontMarkers → updateDependencies → updateTailwindConfig → updateEnvVars → updateFonts → updateFiles → resolveOverwriteCssVars → updateCss → log tree.docs. — [packages/shadcn/src/utils/add-components.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/utils/add-components.ts)
- Fetch trace: resolveRegistryItemsFromRegistries (URL+headers per item, setRegistryHeaders) → fetchRegistryItems → per-item dispatch → fetchRegistry → resolveRegistryUrl → getRegistryHeadersFromContext → fetchWithProxy manual redirect loop → non-ok maps to RegistryUnauthorized/NotFound/Gone/Forbidden/FetchError with RFC-7807 detail parsing → registryItemSchema.parse → RegistryParseError on failure. — [packages/shadcn/src/registry/resolver.ts#L46-133](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/registry/resolver.ts#L46-L133) [packages/shadcn/src/registry/fetcher.ts#L26-141](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/registry/fetcher.ts#L26-L141) [packages/shadcn/src/registry/errors.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/registry/errors.ts)
- build trace: preFlightBuild(resolvePaths) → readRegistryWithIncludes(registryFile) → createRegistryCatalog → per item createRegistryItem → mkdir+write outputDir/<name>.json (nested names OK) → write/copy registry.json to outputDir. — [packages/shadcn/src/commands/build.ts#L35-102](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/commands/build.ts#L35-L102) [packages/shadcn/src/registry/loader.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/registry/loader.ts) [packages/shadcn/src/preflights/preflight-registry.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/preflights/preflight-registry.ts)
- mcp serve trace: shadcn mcp → loadEnvFiles(cwd) → new StdioServerTransport → server.connect → ListToolsRequestSchema returns 7 tools → CallToolRequestSchema → withRegistryContext(handleCallTool, {onGitHubAuthNotice}) → per-tool zod arg parse → getMcpConfig(process.cwd()) → searchRegistries/getRegistryItems → text content responses; errors return isError content blocks. — [packages/shadcn/src/commands/mcp.ts#L98-107](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/commands/mcp.ts#L98-L107) [packages/shadcn/src/mcp/index.ts#L189-598](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/mcp/index.ts#L189-L598)
- Site registry:build trace: pnpm registry:build → build @shadcn/react → @shadcn/helpers → shadcn → bun scripts/build-registry.mts → STYLE_COMBINATIONS from BASES×STYLES → writes registry/bases/__index__.tsx, temp registry/<base-style> trees, registry/__index__.tsx, examples/__index__.tsx → exports public/r/* via the shadcn CLI → copies compiled ui/* into styles/<style>/ui (+ui-rtl for nova) → prettier → cleanup. — [apps/v4/package.json](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/apps/v4/package.json) [apps/v4/scripts/build-registry.mts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/apps/v4/scripts/build-registry.mts) [apps/v4/registry/bases.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/apps/v4/registry/bases.ts) [apps/v4/registry/styles.tsx](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/apps/v4/registry/styles.tsx)
- Dry-run trace: --dry-run/--diff/--view short-circuit before writes — ensureRegistriesInConfig with writeFile:false → dryRunComponents(components, config, {overwrite}) runs the same resolve+transform machinery in memory → formatDryRunResult prints per-file diff or content. — [packages/shadcn/src/commands/add.ts#L289-311](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/commands/add.ts#L289-L311) [packages/shadcn/src/utils/dry-run.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/utils/dry-run.ts) [packages/shadcn/src/utils/dry-run-formatter.ts](https://github.com/shadcn-ui/ui/blob/98a1fe67b439324ddc857f47fbdce056600a4329/packages/shadcn/src/utils/dry-run-formatter.ts)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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