diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index df1316e1..fd439f54 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -145,6 +145,8 @@ jobs:
     permissions:
       contents: read
       id-token: write # npm trusted publishing, so there is no npm token
+    outputs:
+      version: ${{ steps.publish.outputs.version }}
     steps:
       - uses: actions/checkout@v7
         with:
@@ -156,7 +158,12 @@ jobs:
           registry-url: "https://registry.npmjs.org"
       - run: npm ci
       # prepublishOnly builds the bundle.
-      - run: npm publish --access public
+      - name: Publish
+        id: publish
+        run: |
+          version="$(node -p "require('./package.json').version")"
+          npm publish --access public
+          echo "version=$version" >> "$GITHUB_OUTPUT"
 
   # Same shape as publish-npm. Tagging is a separate job, so nothing here needs
   # write access to the repository.
@@ -285,10 +292,47 @@ jobs:
         )
       }}
     runs-on: ubuntu-latest
-    timeout-minutes: 5
+    # npm metadata is normally visible within about five minutes. Leave 2.5x that
+    # window for propagation, plus enough time to mint the token and dispatch.
+    timeout-minutes: 15
     environment: release
     permissions: {}
     steps:
+      - name: Wait for package to become available
+        if: ${{ needs.publish-npm.result == 'success' || needs.publish-npm-preview.outputs.published == 'true' }}
+        env:
+          PACKAGE: "@agentclientprotocol/codex-acp"
+          VERSION: ${{ needs.publish-npm-preview.outputs.version || needs.publish-npm.outputs.version }}
+        #language=bash
+        run: |
+          if [ -z "$VERSION" ]; then
+            echo "::error::The publish job did not report a package version."
+            exit 1
+          fi
+
+          deadline=$((SECONDS + 750))
+          while (( SECONDS < deadline )); do
+            if timeout 10s npm pack "$PACKAGE@$VERSION" \
+              --dry-run \
+              --ignore-scripts \
+              --silent \
+              --registry=https://registry.npmjs.org \
+              --prefer-online \
+              --fetch-retries=0 >/dev/null 2>&1; then
+              echo "$PACKAGE@$VERSION is available from npm."
+              exit 0
+            fi
+
+            remaining=$((deadline - SECONDS))
+            if (( remaining > 0 )); then
+              echo "Waiting for $PACKAGE@$VERSION to become available (${remaining}s remaining)..."
+              sleep 10
+            fi
+          done
+
+          echo "::error::$PACKAGE@$VERSION was not available from npm after 12.5 minutes."
+          exit 1
+
       - name: Generate token scoped to the registry repo
         uses: actions/create-github-app-token@v3
         id: registry-token
diff --git a/docs/RELEASES.md b/docs/RELEASES.md
index fa12b866..e11eccd8 100644
--- a/docs/RELEASES.md
+++ b/docs/RELEASES.md
@@ -61,9 +61,12 @@ handling for preview versions.
 version in the working tree, then publishes to npm. The `prepublishOnly` hook
 builds the bundle before publication. After publishing, `publish-tag-preview`
 creates the tag and `trigger-registry-update` dispatches the registry update
-independently; neither waits for the other. The registry job is shared with the
-stable path. A tag failure can be retried on its own with **Re-run failed jobs**,
-leaving the successful npm publish untouched.
+independently; neither waits for the other. Before dispatching, the registry job
+polls npm for the exact published version for up to 12.5 minutes, including
+downloading its tarball, so the registry never checks while npm is still
+propagating the package. The registry job is shared with the stable path. A tag
+failure can be retried on its own with **Re-run failed jobs**, leaving the
+successful npm publish untouched.
 
 Previews start directly on push, without waiting for the
 [`CI`](../.github/workflows/ci.yml) workflow or the `release-please` job. The
@@ -72,8 +75,9 @@ still requires the `verify` job to pass.
 
 The publish step runs `npm publish --access public --tag preview` and sets
 `published=true` only after it succeeds. Both downstream jobs use that output
-to proceed with preview tagging and registry dispatch. This is a real publish,
-with no dry-run stage.
+to proceed with preview tagging and the registry availability check. This is a
+real publish, with no dry-run stage; the later dry run downloads the published
+tarball to verify it has propagated.
 
 A stable and a preview dispatch can never collide — a release merge publishes
 stable and skips the preview, every other push does the reverse — so the registry