CodeSampleX

Sample

@tailwindcss/postcss 4.3.3

Verified sample for npm @tailwindcss/postcss 4.3.3. The contract ran on node 22 · linux alpine/x64 · docker and passed: tailwindcss() initializes PostCSS…

sha256:c9c6f9979c031bab3a01131575a80e08bbd7ce0a98fd31a82ff1f9f46dc5d2ff

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
3
Signing keys that built it
1
Declared environment node 22.23 linux 24 · ubuntu · glibc 2.39 x64 node 22.23 javascript npm

Verification-run environments

Environment Contract Stages Run
node 22 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1		 2026-08-20
node 22 · linux debian/x64 · docker ed25519:c1973797be207ac4 SKIPPED compile:SKIPPED · contract:SKIPPED · load:SKIPPED · resolve:FAIL
CONTAINER_RUN · node-typescript@1node:22@sha256:8a34c4ab3ea2…		 2026-09-08
node 22 · linux debian/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22@sha256:8a34c4ab3ea2…		 2026-09-08

Case

HOW
Goal
verify pkg:npm/%40tailwindcss/postcss@4.3.3
Packages
Environment
node 22.23.2
Created
2026-08-20T17:16:06Z

Contract

  1. tailwindcss() initializes PostCSS plugin with postcssPlugin metadata property set to '@tailwindcss/postcss'
  2. postcss with @tailwindcss/postcss processes @import 'tailwindcss' and generates core utility CSS for matched candidate classes
  3. postcss with @tailwindcss/postcss compiles custom utilities registered via CSS-first @utility directive when candidates are present
  4. postcss with @tailwindcss/postcss compiles custom variants registered via @variant directive and applies them to candidate utility classes
  5. postcss with @tailwindcss/postcss extends theme tokens with CSS-first @theme directive and emits corresponding theme utility classes
  6. postcss with @tailwindcss/postcss base option restricts candidate file scanning to configured directory
  7. postcss with @tailwindcss/postcss optimize option produces minified CSS when true compared to false

Files

  • PROMPT.md
  • csx.json
  • package-lock.json
  • package.json
  • spec.json
  • src/index.js
  • test/contract.js

Download the source artifact (tar.gz)

Source

PROMPT.md
Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/%40tailwindcss/postcss@4.3.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40tailwindcss/postcss@4.3.3
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.
csx.json
{"case":{"caseId":"case:sha256:cd7cc63f4391ceb582e0e217626a10cb8b888078373c4c96474ce01dd81414e3","constraints":{"executionContext":"node"},"contract":["tailwindcss() initializes PostCSS plugin with postcssPlugin metadata property set to '@tailwindcss/postcss'","postcss with @tailwindcss/postcss processes @import 'tailwindcss' and generates core utility CSS for matched candidate classes","postcss with @tailwindcss/postcss compiles custom utilities registered via CSS-first @utility directive when candidates are present","postcss with @tailwindcss/postcss compiles custom variants registered via @variant directive and applies them to candidate utility classes","postcss with @tailwindcss/postcss extends theme tokens with CSS-first @theme directive and emits corresponding theme utility classes","postcss with @tailwindcss/postcss base option restricts candidate file scanning to configured directory","postcss with @tailwindcss/postcss optimize option produces minified CSS when true compared to false"],"goal":"verify pkg:npm/%40tailwindcss/postcss@4.3.3","kind":"HOW","packages":["pkg:npm/%40tailwindcss/postcss@4.3.3"],"schemaVersion":1},"contractCommand":["node","test/contract.js"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40tailwindcss/postcss@4.3.3"],"schemaVersion":1,"subject":"pkg:npm/%40tailwindcss/postcss@4.3.3","verifierAdapter":"node-typescript@1"}
package-lock.json
{
  "name": "sample-tailwindcss-postcss",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-tailwindcss-postcss",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@tailwindcss/postcss": "4.3.3"
      }
    },
    "node_modules/@alloc/quick-lru": {
      "version": "5.2.0",
      "resolved": "https://registry.npmjs.org/@alloc/quick-lru/-/quick-lru-5.2.0.tgz",
      "integrity": "sha512-UrcABB+4bUrFABwbluTIBErXwvbsU/V7TZWfmbgJfbkwiBuziS9gxdODUyuiecfdGQ85jglMW6juS3+z5TsKLw==",
      "license": "MIT",
      "engines": {
        "node": ">=10"
      },
      "funding": {
        "url": "https://github.com/sponsors/sindresorhus"
      }
    },
    "node_modules/@jridgewell/gen-mapping": {
      "version": "0.3.13",
      "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.13.tgz",
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      "license": "MIT",
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        "@jridgewell/trace-mapping": "^0.3.24"
      }
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    "node_modules/@jridgewell/sourcemap-codec": {
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      "funding": {
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        "url": "https://opencollective.com/parcel"
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package.json
{
  "name": "sample-tailwindcss-postcss",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for @tailwindcss/postcss",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "@tailwindcss/postcss": "4.3.3"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40tailwindcss/postcss@4.3.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40tailwindcss/postcss@4.3.3"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "runtime": "node@22.23.2"
  }
}
src/index.js
const postcss = require('postcss');
const tailwindcss = require('@tailwindcss/postcss');

/**
 * Compiles CSS using the @tailwindcss/postcss plugin.
 * @param {string} css - Input CSS content
 * @param {object} [options] - Options for @tailwindcss/postcss and postcss
 * @returns {Promise<{ css: string, map: any }>}
 */
async function compileTailwind(css, options = {}) {
  const { base, optimize, from = 'input.css', ...rest } = options;
  const plugin = tailwindcss({ base, optimize, ...rest });
  const result = await postcss([plugin]).process(css, { from });
  return {
    css: result.css,
    map: result.map
  };
}

module.exports = {
  compileTailwind,
  tailwindcss
};
test/contract.js
const assert = require('assert');
const fs = require('fs');
const path = require('path');
const postcss = require('postcss');
const tailwindcss = require('@tailwindcss/postcss');
const { compileTailwind } = require('../src/index');

async function runContractTests() {
  const fixturesDir = path.join(__dirname, 'fixtures');
  fs.mkdirSync(fixturesDir, { recursive: true });

  try {
    // 1. Assert plugin initialization and metadata
    const pluginInstance = tailwindcss();
    assert.strictEqual(typeof tailwindcss, 'function', 'Plugin export must be a function');
    assert.strictEqual(pluginInstance.postcssPlugin, '@tailwindcss/postcss', 'Plugin name must be @tailwindcss/postcss');
    assert.strictEqual(tailwindcss.postcss, true, 'Plugin must define postcss property as true');

    // Create source template containing candidate classes
    const srcDir = path.join(fixturesDir, 'src');
    fs.mkdirSync(srcDir, { recursive: true });
    const htmlPath = path.join(srcDir, 'index.html');
    fs.writeFileSync(
      htmlPath,
      '<div class="flex p-4 custom-badge custom-box hocus:underline bg-brand-primary"></div>',
      'utf8'
    );

    // 2. Assert @import "tailwindcss" compiles core utilities matching candidates
    const baseCss = '@import "tailwindcss";';
    const baseResult = await compileTailwind(baseCss, {
      base: srcDir,
      from: path.join(srcDir, 'styles.css')
    });
    assert(baseResult.css.includes('.flex'), 'Output CSS should contain .flex utility');
    assert(baseResult.css.includes('.p-4'), 'Output CSS should contain .p-4 utility');

    // 3. Assert @utility directive compiles custom utility when candidates are present
    const utilityCss = `
      @import "tailwindcss";
      @utility custom-badge {
        padding: 0.25rem 0.5rem;
        border-radius: 9999px;
      }
    `;
    const utilityResult = await compileTailwind(utilityCss, {
      base: srcDir,
      from: path.join(srcDir, 'utility.css')
    });
    assert(utilityResult.css.includes('.custom-badge'), 'Output CSS should contain .custom-badge class');
    assert(utilityResult.css.includes('padding: 0.25rem 0.5rem'), 'Output CSS should include custom utility declarations');

    // 4. Assert @variant directive registers custom variant and compiles variant utility
    const variantCss = `
      @import "tailwindcss";
      @variant hocus (&:hover, &:focus);
    `;
    const variantResult = await compileTailwind(variantCss, {
      base: srcDir,
      from: path.join(srcDir, 'variant.css')
    });
    const hasHocusRule = variantResult.css.includes('.hocus\\:underline:hover') ||
                         variantResult.css.includes('.hocus\\:underline:focus') ||
                         variantResult.css.includes('hocus\\:underline');
    assert(hasHocusRule, 'Output CSS should contain compiled hocus variant selector');

    // 5. Assert @theme directive extends theme tokens and generates theme utilities
    const themeCss = `
      @import "tailwindcss";
      @theme {
        --color-brand-primary: #3b82f6;
      }
    `;
    const themeResult = await compileTailwind(themeCss, {
      base: srcDir,
      from: path.join(srcDir, 'theme.css')
    });
    assert(themeResult.css.includes('.bg-brand-primary'), 'Output CSS should contain .bg-brand-primary utility class');
    assert(themeResult.css.includes('--color-brand-primary: #3b82f6') || themeResult.css.includes('#3b82f6'), 'Theme token definition should be emitted in CSS');

    // 6. Assert base option restricts candidate file scanning to configured directory
    const emptyDir = path.join(fixturesDir, 'empty');
    fs.mkdirSync(emptyDir, { recursive: true });
    const scopedResult = await compileTailwind(baseCss, {
      base: emptyDir,
      from: path.join(emptyDir, 'scoped.css')
    });
    assert(!scopedResult.css.includes('.p-4'), 'CSS scoped to empty directory should not emit unused candidate utilities');

    // 7. Assert optimize option minifies CSS when true compared to false
    const unoptimized = await compileTailwind(baseCss, {
      base: srcDir,
      optimize: false,
      from: path.join(srcDir, 'unopt.css')
    });
    const optimized = await compileTailwind(baseCss, {
      base: srcDir,
      optimize: true,
      from: path.join(srcDir, 'opt.css')
    });
    assert(optimized.css.length < unoptimized.css.length, 'Optimized CSS output should be shorter in byte length than unoptimized output');

    console.log('All @tailwindcss/postcss@4.3.3 contract assertions passed.');
  } finally {
    fs.rmSync(fixturesDir, { recursive: true, force: true });
  }
}

runContractTests().catch((err) => {
  console.error('Contract test failed:', err);
  process.exit(1);
});

Origin Seeder

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