diff --git a/.github/workflows/kiro-extension.yml b/.github/workflows/kiro-extension.yml
index b41edb5..aad5a34 100644
--- a/.github/workflows/kiro-extension.yml
+++ b/.github/workflows/kiro-extension.yml
@@ -174,27 +174,57 @@ jobs:
 
           gh release upload "$TAG" release/*.vsix --clobber
 
-      # Publishes the moment THIS platform is ready, without waiting for the
-      # others. Only ever runs from a release tag.
+  # Uploading to the registry is an HTTP request, not a build, so it does not need
+  # the platform it targets. Splitting it out buys two things. The secret can live
+  # under a GitHub environment, which is only readable by a job declaring
+  # `environment:`, and no half-published version is possible: Open VSX treats a
+  # version as immutable, so if one platform failed to build after another had
+  # already published, that gap could never be filled, only superseded by a
+  # higher version.
+  publish:
+    name: publish ${{ matrix.target }}
+    needs: release
+    if: startsWith(github.ref, 'refs/tags/kiro-extension-v')
+    runs-on: ubuntu-22.04
+    timeout-minutes: 15
+
+    # Only needs to read back the build artifact. Stated explicitly so a
+    # restrictive repository default cannot fail the download confusingly.
+    permissions:
+      contents: read
+      actions: read
+
+    # Names the environment holding the OVSX_PAT secret. This must match the
+    # environment exactly or the secret below silently resolves to an empty
+    # string. The environment happens to be named after the secret it carries.
+    environment: OVSX_PAT
+
+    strategy:
+      # One platform failing to upload must not strand the others.
+      fail-fast: false
+      matrix:
+        target: [darwin-arm64, darwin-x64, win32-x64, linux-x64]
+
+    defaults:
+      run:
+        working-directory: kiro-extension
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - uses: actions/download-artifact@v4
+        with:
+          name: vsix-${{ matrix.target }}
+          path: kiro-extension/release
+
       - name: Publish ${{ matrix.target }} to Open VSX
-        if: startsWith(github.ref, 'refs/tags/kiro-extension-v')
         env:
           OVSX_PAT: ${{ secrets.OVSX_PAT }}
-        shell: bash
-        run: |
-          if [ -z "$OVSX_PAT" ]; then
-            echo "OVSX_PAT resolved to an empty string, refusing to publish." >&2
-            echo "" >&2
-            echo "If you added it under Settings > Environments, it is only" >&2
-            echo "visible to a job that declares 'environment:'. This job does" >&2
-            echo "not, deliberately: an environment with protection rules would" >&2
-            echo "also gate every pull request build." >&2
-            echo "" >&2
-            echo "Add it as a repository secret instead:" >&2
-            echo "Settings > Secrets and variables > Actions > New repository secret" >&2
-            exit 1
-          fi
-          node scripts/release.mjs --publish
+        run: node scripts/publish.mjs --target=${{ matrix.target }}
 
   # A platform-specific VSIX declares TargetPlatform, and a mismatched host
   # refuses to install it. This produces one file with every companion binary and
diff --git a/kiro-extension/scripts/publish.mjs b/kiro-extension/scripts/publish.mjs
new file mode 100644
index 0000000..e27ffa3
--- /dev/null
+++ b/kiro-extension/scripts/publish.mjs
@@ -0,0 +1,94 @@
+/**
+ * Publishes an already-packaged VSIX to Open VSX, the registry Kiro installs
+ * from. Packaging happens on the platform that can compile the native mascot;
+ * uploading is just an HTTP request, so it is split out and runs anywhere.
+ *
+ *   node scripts/publish.mjs --target darwin-arm64
+ *
+ * Expects the matching VSIX to already exist in release/, which is how the CI
+ * publish job consumes the artifact the build job produced.
+ */
+import { spawnSync } from 'node:child_process';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const root = path.dirname(path.dirname(fileURLToPath(import.meta.url)));
+const manifest = JSON.parse(await fs.readFile(path.join(root, 'package.json'), 'utf-8'));
+
+const target = process.argv.find((arg) => arg.startsWith('--target='))?.split('=')[1];
+if (!target) {
+  console.error('[doraemon] usage: node scripts/publish.mjs --target=<platform>');
+  process.exit(1);
+}
+
+if (!process.env['OVSX_PAT']) {
+  console.error('[doraemon] OVSX_PAT resolved to an empty string, refusing to publish.');
+  console.error('');
+  console.error('[doraemon] In CI this usually means the secret lives under an');
+  console.error('[doraemon] environment, but the job did not declare "environment:".');
+  console.error('[doraemon] Locally, create a token at:');
+  console.error('[doraemon] https://open-vsx.org/user-settings/tokens');
+  process.exit(1);
+}
+
+/*
+ * The tag names the release but the version comes from package.json. Publishing a
+ * mismatch is unrecoverable: Open VSX treats a version as immutable, so the wrong
+ * number cannot be replaced afterwards, only superseded by a higher one.
+ */
+const tag = process.env['GITHUB_REF_NAME'];
+if (tag?.startsWith('kiro-extension-v')) {
+  const tagged = tag.slice('kiro-extension-v'.length);
+  if (tagged !== manifest.version) {
+    console.error(`[doraemon] tag ${tag} does not match package.json ${manifest.version}.`);
+    console.error('[doraemon] bump the version and retag, rather than publishing a mismatch.');
+    process.exit(1);
+  }
+}
+
+// Mirrors the name release.mjs packages under, so no globbing is needed.
+const vsix = path.join(root, 'release', `${manifest.name}-${manifest.version}-${target}.vsix`);
+try {
+  await fs.access(vsix);
+} catch {
+  console.error(`[doraemon] ${path.relative(root, vsix)} is missing.`);
+  console.error('[doraemon] package it first, or check the build artifact was downloaded.');
+  process.exit(1);
+}
+
+const { size } = await fs.stat(vsix);
+console.log(`[doraemon] publishing ${path.relative(root, vsix)} (${(size / 1024 / 1024).toFixed(2)} MB)`);
+
+/*
+ * Publishing into a namespace that does not exist fails outright. Creating it is
+ * idempotent, so doing it here means the first ever release needs no manual step.
+ * Four platforms race to create the same namespace and three will lose, which is
+ * why an "already exists" result is treated as success.
+ */
+console.log(`[doraemon] ensuring namespace "${manifest.publisher}" exists`);
+const namespace = spawnSync('npx', ['--yes', 'ovsx', 'create-namespace', manifest.publisher], {
+  cwd: root,
+  encoding: 'utf-8',
+  shell: process.platform === 'win32',
+});
+const namespaceOutput = `${namespace.stdout ?? ''}${namespace.stderr ?? ''}`;
+if (namespace.status !== 0 && !/already (exists|owned)/i.test(namespaceOutput)) {
+  console.error('[doraemon] could not create the namespace:');
+  console.error(namespaceOutput.trim());
+  console.error('[doraemon] claim it manually at https://open-vsx.org and retry.');
+  process.exit(1);
+}
+
+console.log(`[doraemon] uploading ${target} as "${manifest.publisher}"`);
+const publish = spawnSync('npx', ['--yes', 'ovsx', 'publish', vsix, '--target', target], {
+  cwd: root,
+  stdio: 'inherit',
+  shell: process.platform === 'win32',
+});
+if (publish.status !== 0) {
+  console.error(`[doraemon] publishing ${target} failed`);
+  process.exit(publish.status ?? 1);
+}
+
+console.log(`[doraemon] published ${manifest.name} ${manifest.version} (${target})`);