diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index c9cf3de..4a0fbe1 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -9,7 +9,8 @@
     {
       "name": "unity",
       "source": "./",
-      "description": "Unity's official game development plugin. Build, monetize, and operate Unity games with guidance grounded in Unity's documented practices."
+      "description": "Unity's official game development plugin. Build, monetize, and operate Unity games with guidance grounded in Unity's documented practices.",
+      "category": "Developer Tools"
     }
   ]
 }
diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
index a7df8ed..5097208 100644
--- a/.claude-plugin/plugin.json
+++ b/.claude-plugin/plugin.json
@@ -1,5 +1,6 @@
 {
   "name": "unity",
+  "displayName": "Unity",
   "version": "0.1.8-beta",
   "description": "Unity's official plugin for coding agents, with curated skills for game development, monetization, and performance optimization.",
   "author": {
@@ -7,6 +8,7 @@
     "url": "https://unity.com"
   },
   "homepage": "https://unity.com",
+  "repository": "https://github.com/Unity-Technologies/unity-agent-plugin",
   "license": "LicenseRef-Unity-Companion-License",
   "keywords": [
     "unity",
@@ -21,5 +23,10 @@
     "localization",
     "multiplayer",
     "shader-graph"
-  ]
+  ],
+  "icon": "./assets/unity-tile.svg",
+  "documentationUrl": "https://github.com/Unity-Technologies/unity-agent-plugin#readme",
+  "supportUrl": "https://github.com/Unity-Technologies/unity-agent-plugin/issues",
+  "privacyPolicyUrl": "https://unity.com/legal/privacy-policy",
+  "termsOfServiceUrl": "https://unity.com/legal/terms-of-service"
 }
diff --git a/.codex-plugin/plugin.json b/.codex-plugin/plugin.json
index da8c81a..1bc5e8d 100644
--- a/.codex-plugin/plugin.json
+++ b/.codex-plugin/plugin.json
@@ -7,6 +7,7 @@
     "url": "https://unity.com"
   },
   "homepage": "https://unity.com",
+  "repository": "https://github.com/Unity-Technologies/unity-agent-plugin",
   "license": "LicenseRef-Unity-Companion-License",
   "keywords": [
     "unity",
@@ -45,7 +46,6 @@
       "Set up a tilemap level with rule tiles for my 2D Unity game.",
       "Help me implement in-app purchases and set up ad mediation with LevelPlay.",
       "Set up multiplayer lobbies and networking for my Unity game."
-    ],
-    "screenshots": []
+    ]
   }
 }
diff --git a/.github/workflows/validate-manifests.yml b/.github/workflows/validate-manifests.yml
new file mode 100644
index 0000000..ada8e15
--- /dev/null
+++ b/.github/workflows/validate-manifests.yml
@@ -0,0 +1,37 @@
+name: Validate manifests
+
+on:
+  pull_request:
+    paths:
+      - '.claude-plugin/**'
+      - '.codex-plugin/**'
+      - '.antigravity-plugin/**'
+      - '.agents/**'
+      - '.github/README.md'
+      - 'scripts/plugin-metadata.json'
+      - 'scripts/*.mts'
+      - 'scripts/tsconfig.json'
+      - '.github/workflows/validate-manifests.yml'
+  push:
+    branches: [main]
+    paths:
+      - '.claude-plugin/**'
+      - '.codex-plugin/**'
+      - '.antigravity-plugin/**'
+      - '.agents/**'
+      - 'scripts/plugin-metadata.json'
+
+jobs:
+  shared-values:
+    name: Manifests share one set of values
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 24
+      - name: Typecheck the scripts
+        run: |
+          npm install --no-save --no-audit --no-fund typescript@5 @types/node@24
+          npx tsc -p scripts/tsconfig.json
+      - run: node scripts/sync-manifests.mts --check
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..849ddff
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+dist/
diff --git a/scripts/build-codex-zip.mts b/scripts/build-codex-zip.mts
new file mode 100644
index 0000000..2204a8c
--- /dev/null
+++ b/scripts/build-codex-zip.mts
@@ -0,0 +1,90 @@
+#!/usr/bin/env node
+// Builds the zip uploaded to OpenAI's plugin portal for a Codex release.
+//
+//   node scripts/build-codex-zip.mts            writes dist/unity-codex-<version>.zip
+//
+// Run it on a clean checkout of merged main, after the version bump. The zip holds one folder,
+// `unity`, with the skills (no evals/ or tests/), both manifests, the README, the license and
+// the logos the manifests reference. It refuses to build if the manifests disagree on
+// the version or drift from scripts/plugin-metadata.json.
+import { execFileSync } from 'node:child_process';
+import { cpSync, existsSync, mkdirSync, mkdtempSync, readdirSync, readFileSync, rmSync, statSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { basename, join, resolve } from 'node:path';
+
+const root = resolve(import.meta.dirname, '..');
+const meta: { version: string } = JSON.parse(
+  readFileSync(join(root, 'scripts/plugin-metadata.json'), 'utf8'),
+);
+
+// 1. The manifests must already carry the release version.
+execFileSync(process.execPath, [join(root, 'scripts/sync-manifests.mts'), '--check'], {
+  cwd: root,
+  stdio: 'inherit',
+});
+const manifests = ['.codex-plugin/plugin.json', '.claude-plugin/plugin.json'];
+for (const file of manifests) {
+  const { version } = JSON.parse(readFileSync(join(root, file), 'utf8')) as { version: string };
+  if (version !== meta.version) fail(`${file} is at ${version}, expected ${meta.version}`);
+}
+
+// 2. Stage the package as <tmp>/unity.
+const excluded = new Set(['evals', 'tests', '.DS_Store', 'Thumbs.db']);
+const contents = [
+  'skills',
+  '.codex-plugin',
+  '.claude-plugin',
+  'README.md',
+  'LICENSE.md',
+  'assets/unity.svg',
+  'assets/unity-small.svg',
+  'assets/unity-tile.svg', // the icon .claude-plugin/plugin.json points to
+];
+const stage = mkdtempSync(join(tmpdir(), 'unity-codex-'));
+const pkg = join(stage, 'unity');
+try {
+  for (const entry of contents) {
+    const from = join(root, entry);
+    if (!existsSync(from)) fail(`missing ${entry}`);
+    cpSync(from, join(pkg, entry), {
+      recursive: true,
+      filter: (src) => !excluded.has(basename(src)),
+    });
+  }
+
+  // 3. Check what was staged before zipping it.
+  const skills = readdirSync(join(pkg, 'skills')).filter((d) =>
+    existsSync(join(pkg, 'skills', d, 'SKILL.md')),
+  );
+  const codex = JSON.parse(readFileSync(join(pkg, '.codex-plugin/plugin.json'), 'utf8')) as {
+    interface?: { logo?: string; composerIcon?: string };
+  };
+  const assets = [codex.interface?.logo, codex.interface?.composerIcon];
+  for (const asset of assets.filter((a): a is string => typeof a === 'string')) {
+    if (!existsSync(join(pkg, asset))) fail(`the Codex manifest references ${asset}, which is not in the package`);
+  }
+
+  // 4. Zip it. Windows and macOS ship bsdtar, which writes zip archives; Linux uses zip.
+  const dist = join(root, 'dist');
+  mkdirSync(dist, { recursive: true });
+  const out = join(dist, `unity-codex-${meta.version}.zip`);
+  rmSync(out, { force: true });
+  if (process.platform === 'linux') {
+    execFileSync('zip', ['-r', '-X', '-q', out, 'unity'], { cwd: stage, stdio: 'inherit' });
+  } else {
+    const tar =
+      process.platform === 'win32' ? join(process.env.SystemRoot ?? 'C:\Windows', 'System32', 'tar.exe') : 'tar';
+    execFileSync(tar, ['--format', 'zip', '-cf', out, 'unity'], { cwd: stage, stdio: 'inherit' });
+  }
+
+  console.log(`Built ${out}`);
+  console.log(`  version ${meta.version}, ${skills.length} skills, ${(statSync(out).size / 1024).toFixed(0)} KB`);
+  console.log('Next: upload it at https://platform.openai.com/plugins (Upload plugin to make changes).');
+} finally {
+  rmSync(stage, { recursive: true, force: true });
+}
+
+function fail(message: string): never {
+  console.error(`build-codex-zip: ${message}`);
+  process.exit(1);
+}
diff --git a/scripts/plugin-metadata.json b/scripts/plugin-metadata.json
new file mode 100644
index 0000000..0d3576c
--- /dev/null
+++ b/scripts/plugin-metadata.json
@@ -0,0 +1,25 @@
+{
+  "version": "0.1.8-beta",
+  "author": {
+    "name": "Unity Technologies",
+    "url": "https://unity.com"
+  },
+  "homepage": "https://unity.com",
+  "repository": "https://github.com/Unity-Technologies/unity-agent-plugin",
+  "license": "LicenseRef-Unity-Companion-License",
+  "category": "Developer Tools",
+  "keywords": [
+    "unity",
+    "gamedev",
+    "game-development",
+    "ui-toolkit",
+    "ugui",
+    "2d",
+    "tilemap",
+    "in-app-purchases",
+    "monetization",
+    "localization",
+    "multiplayer",
+    "shader-graph"
+  ]
+}
diff --git a/scripts/sync-manifests.mts b/scripts/sync-manifests.mts
new file mode 100644
index 0000000..78167ce
--- /dev/null
+++ b/scripts/sync-manifests.mts
@@ -0,0 +1,127 @@
+#!/usr/bin/env node
+// Keeps the values every platform manifest shares (version, author, homepage, repository,
+// license, keywords, category) in one place: scripts/plugin-metadata.json.
+//
+//   node scripts/sync-manifests.mts          write the shared values into every manifest
+//   node scripts/sync-manifests.mts --check  fail if any manifest has drifted (CI runs this)
+//
+// To release, change "version" in plugin-metadata.json and run the script without --check.
+// Platform-only fields (descriptions, the Codex interface block, Antigravity prompts) stay in
+// each manifest and are not touched.
+import { readFileSync, writeFileSync } from 'node:fs';
+
+type Json = string | number | boolean | null | Json[] | { [key: string]: Json };
+type JsonObject = { [key: string]: Json };
+
+interface Metadata {
+  version: string;
+  author: { name: string; url?: string; email?: string };
+  homepage: string;
+  repository: string;
+  license: string;
+  category: string;
+  keywords: string[];
+}
+
+interface Marketplace extends JsonObject {
+  plugins: JsonObject[];
+}
+
+const check = process.argv.includes('--check');
+const meta: Metadata = JSON.parse(readFileSync('scripts/plugin-metadata.json', 'utf8'));
+const shared = ['version', 'author', 'homepage', 'repository', 'license', 'keywords'] as const;
+
+// Each target names a manifest and where each shared key lives in it.
+const targets: { file: string; set: (manifest: JsonObject) => void }[] = [
+  { file: '.claude-plugin/plugin.json', set: (m) => assign(m, shared) },
+  {
+    file: '.codex-plugin/plugin.json',
+    set: (m) => {
+      assign(m, shared);
+      (m.interface as JsonObject).category = meta.category;
+    },
+  },
+  {
+    // No category: agy 1.4 reports it as an unknown field, which fails `validate --strict`.
+    file: '.antigravity-plugin/plugin.json',
+    set: (m) => {
+      assign(m, shared);
+      delete m.category;
+    },
+  },
+  {
+    // The entry must not carry a version: plugin.json wins at install, and validate warns.
+    file: '.claude-plugin/marketplace.json',
+    set: (m) => {
+      const entry = pluginEntry(m as Marketplace);
+      delete entry.version;
+      entry.category = meta.category;
+    },
+  },
+  {
+    file: '.agents/plugins/marketplace.json',
+    set: (m) => {
+      pluginEntry(m as Marketplace).category = meta.category;
+    },
+  },
+];
+
+// Where a key goes when a manifest doesn't have it yet, so new keys sit beside related ones.
+const anchors: Record<string, string> = { repository: 'homepage', license: 'repository' };
+
+function assign(manifest: JsonObject, keys: readonly (keyof Metadata)[]): void {
+  for (const key of keys) setKey(manifest, key, structuredClone(meta[key]));
+}
+
+function setKey(obj: JsonObject, key: string, value: Json): void {
+  const anchor = anchors[key];
+  if (key in obj || !anchor || !(anchor in obj)) {
+    obj[key] = value;
+    return;
+  }
+  const entries = Object.entries(obj);
+  const at = entries.findIndex(([k]) => k === anchor) + 1;
+  entries.splice(at, 0, [key, value]);
+  for (const k of Object.keys(obj)) delete obj[k];
+  Object.assign(obj, Object.fromEntries(entries));
+}
+
+function pluginEntry(marketplace: Marketplace): JsonObject {
+  const entry = marketplace.plugins?.find((p) => p.name === 'unity');
+  if (!entry) throw new Error('no "unity" entry in plugins[]');
+  return entry;
+}
+
+const drifted: string[] = [];
+for (const { file, set } of targets) {
+  const before = readFileSync(file, 'utf8').replace(/\r\n/g, '\n');
+  const manifest = JSON.parse(before);
+  set(manifest);
+  const after = `${JSON.stringify(manifest, null, 2)}\n`;
+  if (after === before) continue;
+  if (check) drifted.push(file);
+  else writeFileSync(file, after);
+}
+
+// The sample `agy plugin list` and `codex plugin list` output in the README shows the version.
+const readme = '.github/README.md';
+const readmeText = readFileSync(readme, 'utf8');
+const stale = [...readmeText.matchAll(/\b0\.\d+\.\d+(?:-[a-z0-9.]+)?\b/g)]
+  .map((m) => m[0])
+  .filter((v) => v !== meta.version);
+if (stale.length > 0) {
+  if (check) drifted.push(`${readme} (shows ${[...new Set(stale)].join(', ')})`);
+  else writeFileSync(readme, readmeText.replaceAll(new RegExp(stale.map(escape).join('|'), 'g'), meta.version));
+}
+
+function escape(s: string): string {
+  return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+}
+
+if (drifted.length > 0) {
+  console.error('These files differ from scripts/plugin-metadata.json:');
+  for (const file of drifted) console.error(`  ${file}`);
+  console.error('Run `node scripts/sync-manifests.mts` and commit the result.');
+  process.exit(1);
+}
+console.log(check ? 'Manifests match scripts/plugin-metadata.json' : 'Manifests updated');
diff --git a/scripts/tsconfig.json b/scripts/tsconfig.json
new file mode 100644
index 0000000..3b6b4b4
--- /dev/null
+++ b/scripts/tsconfig.json
@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "es2023",
+    "module": "nodenext",
+    "moduleResolution": "nodenext",
+    "strict": true,
+    "noEmit": true,
+    "allowImportingTsExtensions": true,
+    "erasableSyntaxOnly": true,
+    "types": ["node"],
+    "skipLibCheck": true
+  },
+  "include": ["*.mts"]
+}