thesysdev · abhithesys · Apr 8, 2026 · Apr 3, 2026 · Apr 8, 2026 · Apr 8, 2026
diff --git a/.github/workflows/publish-npm-package.yml b/.github/workflows/publish-npm-package.yml
@@ -16,6 +16,7 @@ on:
           - react-headless
           - react-lang
           - react-email
+          - lang-core
           - openui-cli
           - svelte-lang
           - vue-lang

diff --git a/docs/next.config.mjs b/docs/next.config.mjs
@@ -9,7 +9,6 @@ const withMDX = createMDX();
 /** @type {import('next').NextConfig} */
 const config = {
   serverExternalPackages: ["@takumi-rs/image-response"],
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-lang", "@openuidev/react-headless"],
   turbopack: {
     root: dirname(dirname(__dirname)),
   },

diff --git a/eslint.config.cjs b/eslint.config.cjs
@@ -27,6 +27,7 @@ module.exports = [
       "**/__tests__/**/*.{ts,tsx}",
       "**/*.test.{ts,tsx}",
       "**/*.spec.{ts,tsx}",
+      "*.config.ts",
     ],
     languageOptions: {
       parser: typescript,

diff --git a/examples/form-generator/next.config.ts b/examples/form-generator/next.config.ts
@@ -2,7 +2,6 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   turbopack: {},
-  transpilePackages: ["@openuidev/react-headless", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/mastra-chat/next.config.ts b/examples/mastra-chat/next.config.ts
@@ -2,7 +2,6 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-headless", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/multi-agent-chat/next.config.ts b/examples/multi-agent-chat/next.config.ts
@@ -2,7 +2,6 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/openui-artifact-demo/next.config.ts b/examples/openui-artifact-demo/next.config.ts
@@ -3,7 +3,6 @@ import type { NextConfig } from "next";
 const nextConfig: NextConfig = {
   output: "standalone",
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-headless", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/openui-chat/next.config.ts b/examples/openui-chat/next.config.ts
@@ -3,7 +3,6 @@ import type { NextConfig } from "next";
 const nextConfig: NextConfig = {
   output: "standalone",
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-headless", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/openui-dashboard/next.config.ts b/examples/openui-dashboard/next.config.ts
@@ -3,7 +3,6 @@ import type { NextConfig } from "next";
 const nextConfig: NextConfig = {
   output: "standalone",
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-headless", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/react-email/next.config.ts b/examples/react-email/next.config.ts
@@ -1,11 +1,5 @@
 import type { NextConfig } from "next";
 
-const nextConfig: NextConfig = {
-  transpilePackages: [
-    "@openuidev/react-headless",
-    "@openuidev/react-lang",
-    "@openuidev/react-email",
-  ],
-};
+const nextConfig: NextConfig = {};
 
 export default nextConfig;
diff --git a/examples/react-email/src/generated/system-prompt.txt b/examples/react-email/src/generated/system-prompt.txt
@@ -14,8 +14,6 @@ You are an AI assistant that responds using openui-lang, a declarative UI langua
 ## Component Signatures
 
 Arguments marked with ? are optional. Sub-components can be inline or referenced; prefer references for better streaming.
-Props typed `ActionExpression` accept an Action([@steps...]) expression. See the Action section for available steps (@ToAssistant, @OpenUrl).
-Props marked `$binding<type>` accept a `$variable` reference for two-way binding.
 
 ### Email Structure
 EmailTemplate(subject: string, previewText?: string, children: (EmailHeading | EmailText | EmailButton | EmailImage | EmailDivider | EmailLink | EmailCodeBlock | EmailCodeInline | EmailMarkdown | EmailArticle | EmailProductCard | EmailFeatureGrid | EmailFeatureList | EmailNumberedSteps | EmailCheckoutTable | EmailPricingCard | EmailTestimonial | EmailSurveyRating | EmailStats | EmailImageGrid | EmailAvatarGroup | EmailAvatarWithText | EmailList | EmailCustomerReview | EmailBentoGrid | EmailSection | EmailColumns | EmailColumn | EmailHeaderSideNav | EmailHeaderCenteredNav | EmailHeaderSocial | EmailFooterCentered | EmailFooterTwoColumn)[]) — Root email template. Renders a live email preview with Copy HTML export. Always provide a subject line.
@@ -135,50 +133,6 @@ EmailBentoGrid(heroTitle: string, heroDescription: string, heroLinkText?: string
 - EmailBentoGrid: Bento-style layout with a dark hero section on top and product cards below. Pass EmailBentoItem children.
 - Great for product showcase and marketing emails.
 
-## Built-in Functions
-
-Data functions prefixed with `@` to distinguish from components. These are the ONLY functions available — do NOT invent new ones.
-Use @-prefixed built-in functions (@Count, @Sum, @Avg, @Min, @Max, @Round) on Query results — do NOT hardcode computed values.
-
-@Count(array) → number — Returns array length
-@First(array) → element — Returns first element of array
-@Last(array) → element — Returns last element of array
-@Sum(numbers[]) → number — Sum of numeric array
-@Avg(numbers[]) → number — Average of numeric array
-@Min(numbers[]) → number — Minimum value in array
-@Max(numbers[]) → number — Maximum value in array
-@Sort(array, field, direction?) → sorted array — Sort array by field. Direction: "asc" (default) or "desc"
-@Filter(array, field, operator: "==" | "!=" | ">" | "<" | ">=" | "<=" | "contains", value) → filtered array — Filter array by field value
-@Round(number, decimals?) → number — Round to N decimal places (default 0)
-@Abs(number) → number — Absolute value
-@Floor(number) → number — Round down to nearest integer
-@Ceil(number) → number — Round up to nearest integer
-@Each(array, varName, template) — Evaluate template for each element. varName is the loop variable — use it ONLY inside the template expression (inline). Do NOT create a separate statement for the template.
-
-Builtins compose — output of one is input to the next:
-`@Count(@Filter(data.rows, "field", "==", "val"))` for KPIs/chart values, `@Round(@Avg(data.rows.score), 1)`, `@Each(data.rows, "item", Comp(item.field))` for per-item rendering.
-Array pluck: `data.rows.field` extracts a field from every row → use with @Sum, @Avg, charts, tables.
-
-IMPORTANT @Each rule: The loop variable (e.g. "item") is ONLY available inside the @Each template expression. Always inline the template — do NOT extract it to a separate statement.
-CORRECT: `Col("Actions", @Each(rows, "t", Button("Edit", Action([@Set($id, t.id)]))))`
-WRONG: `myBtn = Button("Edit", Action([@Set($id, t.id)]))` then `Col("Actions", @Each(rows, "t", myBtn))` — t is undefined in myBtn.
-
-## Action — Button Behavior
-
-Action([@steps...]) wires button clicks to operations. Steps are @-prefixed built-in actions. Steps execute in order.
-Buttons without an explicit Action prop automatically send their label to the assistant (equivalent to Action([@ToAssistant(label)])).
-
-Available steps:
-- @ToAssistant("message") — Send a message to the assistant (for conversational buttons like "Tell me more", "Explain this")
-- @OpenUrl("https://...") — Navigate to a URL
-
-Example — simple nav:
-```
-viewBtn = Button("View", Action([@OpenUrl("https://example.com")]))
-```
-
-- Action can be assigned to a variable or inlined: Button("Go", onSubmit) and Button("Go", Action([...])) both work
-
 ## Hoisting & Streaming (CRITICAL)
 
 openui-lang supports hoisting: a reference can be used BEFORE it is defined. The parser resolves all references after the full input is parsed.
@@ -187,10 +141,8 @@ During streaming, the output is re-parsed on every chunk. Undefined references a
 
 **Recommended statement order for optimal streaming:**
 1. `root = EmailTemplate(...)` — UI shell appears immediately
-2. $variable declarations — state ready for bindings
-3. Query statements — defaults resolve immediately so components render with data
-4. Component definitions — fill in with data already available
-5. Data values — leaf content last
+2. Component definitions — fill in as they stream
+3. Data values — leaf content last
 
 Always write the root = EmailTemplate(...) statement first so the UI shell appears immediately, even before child data has streamed in.
 

diff --git a/examples/shadcn-chat/next.config.ts b/examples/shadcn-chat/next.config.ts
@@ -2,7 +2,6 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-headless", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/vercel-ai-chat/next.config.ts b/examples/vercel-ai-chat/next.config.ts
@@ -2,7 +2,6 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   turbopack: {},
-  transpilePackages: ["@openuidev/react-ui", "@openuidev/react-lang"],
 };
 
 export default nextConfig;
diff --git a/examples/vue-chat/nuxt.config.ts b/examples/vue-chat/nuxt.config.ts
@@ -20,7 +20,4 @@ export default defineNuxtConfig({
       "@tailwindcss/postcss": {},
     },
   },
-  build: {
-    transpile: ["@openuidev/vue-lang", "@openuidev/lang-core"],
-  },
 });
diff --git a/package.json b/package.json
@@ -7,6 +7,7 @@
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "devDependencies": {
+    "@arethetypeswrong/cli": "^0.18.2",
     "@typescript-eslint/eslint-plugin": "^8.56.1",
     "eslint": "^9.0.0",
     "eslint-config-prettier": "^10.1.8",
@@ -17,6 +18,8 @@
     "eslint-plugin-unused-imports": "^4.4.1",
     "prettier": "^3.2.5",
     "prettier-plugin-organize-imports": "^3.2.4",
+    "publint": "^0.3.18",
+    "tsdown": "^0.21.7",
     "typescript": "^5.9.3"
   },
   "keywords": [

diff --git a/packages/lang-core/eslint.config.cjs b/packages/lang-core/eslint.config.cjs
@@ -22,6 +22,7 @@ module.exports = [
       "**/__tests__/**/*.{ts,tsx}",
       "**/*.test.{ts,tsx}",
       "**/*.spec.{ts,tsx}",
+      "*.config.ts",
     ],
     languageOptions: {
       parser: typescript,

diff --git a/packages/lang-core/package.json b/packages/lang-core/package.json
@@ -1,38 +1,47 @@
 {
   "name": "@openuidev/lang-core",
-  "version": "0.1.3",
+  "version": "0.2.0",
   "description": "Framework-agnostic core for OpenUI Lang: parser, prompt generation, validation, and type definitions",
   "license": "MIT",
   "type": "module",
-  "main": "dist/index.js",
-  "types": "dist/index.d.ts",
+  "main": "dist/index.cjs",
+  "module": "dist/index.mjs",
+  "types": "dist/index.d.cts",
+  "sideEffects": false,
   "files": [
     "dist",
     "README.md"
   ],
   "exports": {
     ".": {
-      "types": "./dist/index.d.ts",
-      "import": "./dist/index.js",
-      "default": "./dist/index.js"
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
+      }
     }
   },
   "scripts": {
     "test": "vitest run",
-    "build": "tsc -p .",
-    "watch": "tsc -p . --watch",
+    "build": "tsdown",
+    "watch": "tsdown --watch",
+    "typecheck": "tsc --noEmit",
     "lint:check": "eslint ./src",
     "lint:fix": "eslint ./src --fix",
     "format:fix": "prettier --write ./src",
     "format:check": "prettier --check ./src",
+    "check:publint": "publint",
+    "check:attw": "attw --pack .",
     "prepare": "pnpm run build",
+    "prepublishOnly": "pnpm run check:publint && pnpm run check:attw",
     "ci": "pnpm run lint:check && pnpm run format:check"
   },
-  "dependencies": {
-    "zod": "^4.0.0"
-  },
   "peerDependencies": {
-    "@modelcontextprotocol/sdk": ">=1.0.0"
+    "@modelcontextprotocol/sdk": ">=1.0.0",
+    "zod": "^4.0.0"
   },
   "peerDependenciesMeta": {
     "@modelcontextprotocol/sdk": {

diff --git a/packages/lang-core/tsconfig.json b/packages/lang-core/tsconfig.json
@@ -8,7 +8,7 @@
     "module": "ESNext",
     "outDir": "./dist",
     "rootDir": "./src",
-    "declaration": true,
+    "noEmit": true,
     "noPropertyAccessFromIndexSignature": false,
     "noUncheckedIndexedAccess": false,
     "noImplicitReturns": false,

diff --git a/packages/lang-core/tsdown.config.ts b/packages/lang-core/tsdown.config.ts
@@ -0,0 +1,14 @@
+import { defineConfig } from "tsdown";
+
+export default defineConfig({
+  entry: ["src/index.ts"],
+  format: ["esm", "cjs"],
+  dts: true,
+  sourcemap: true,
+  target: "es2022",
+  outDir: "dist",
+  clean: true,
+  deps: {
+    neverBundle: [/^[^./]/],
+  },
+});
diff --git a/packages/react-email/package.json b/packages/react-email/package.json
@@ -1,40 +1,51 @@
 {
   "name": "@openuidev/react-email",
-  "version": "0.1.3",
+  "version": "0.2.0",
   "description": "React Email components for OpenUI — 44 email building blocks with defineComponent",
   "type": "module",
-  "main": "dist/index.js",
-  "types": "dist/index.d.ts",
+  "main": "dist/index.cjs",
+  "module": "dist/index.mjs",
+  "types": "dist/index.d.cts",
+  "sideEffects": false,
   "exports": {
     ".": {
-      "types": "./dist/index.d.ts",
-      "import": "./dist/index.js",
-      "default": "./dist/index.js"
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
+      }
     }
   },
   "files": [
     "dist",
     "README.md"
   ],
   "scripts": {
-    "build": "tsc -p tsconfig.build.json",
-    "dev": "tsc -p tsconfig.build.json --watch",
+    "build": "tsdown",
+    "dev": "tsdown --watch",
+    "typecheck": "tsc --noEmit",
     "lint": "eslint",
     "lint:check": "eslint ./src",
     "lint:fix": "eslint ./src --fix",
     "format:fix": "prettier --write ./src",
     "format:check": "prettier --check ./src",
+    "check:publint": "publint",
+    "check:attw": "attw --pack .",
     "prepare": "pnpm run build",
+    "prepublishOnly": "pnpm run check:publint && pnpm run check:attw",
     "ci": "pnpm run lint:check && pnpm run format:check"
   },
   "dependencies": {
-    "@react-email/components": "^0.0.41",
-    "zod": "^4.3.6"
+    "@react-email/components": "^0.0.41"
   },
   "peerDependencies": {
     "@openuidev/react-lang": "workspace:*",
     "react": ">=19.0.0",
-    "react-dom": ">=19.0.0"
+    "react-dom": ">=19.0.0",
+    "zod": "^4.3.6"
   },
   "devDependencies": {
     "@types/react": "^19",

diff --git a/packages/react-email/tsconfig.json b/packages/react-email/tsconfig.json
@@ -4,7 +4,6 @@
     "lib": ["dom", "dom.iterable", "esnext"],
     "module": "esnext",
     "moduleResolution": "bundler",
-    "declaration": true,
     "strict": true,
     "noEmit": true,
     "esModuleInterop": true,

diff --git a/packages/react-email/tsdown.config.ts b/packages/react-email/tsdown.config.ts
@@ -0,0 +1,14 @@
+import { defineConfig } from "tsdown";
+
+export default defineConfig({
+  entry: ["src/index.ts"],
+  format: ["esm", "cjs"],
+  dts: true,
+  sourcemap: true,
+  target: "es2022",
+  outDir: "dist",
+  clean: true,
+  deps: {
+    neverBundle: [/^[^./]/],
+  },
+});