diff --git a/.github/workflows/Documentation.yml b/.github/workflows/Documentation.yml
index 49b9b028..455c7dfc 100644
--- a/.github/workflows/Documentation.yml
+++ b/.github/workflows/Documentation.yml
@@ -15,10 +15,14 @@ jobs:
     # re-run this job on every subsequent label add. Only react to 'labeled' when it's
     # this specific label; for other trigger types (synchronize/reopened), fall back to
     # checking the current label set as before.
+    # On a PR, `run documentation` is the only trigger. `documentation push preview` is a
+    # modifier: with `run documentation` present, the build also deploys its preview.
     if: >
       github.event_name != 'pull_request' ||
-      (github.event.action == 'labeled' && github.event.label.name == 'run documentation') ||
-      (github.event.action != 'labeled' && contains(github.event.pull_request.labels.*.name, 'run documentation'))
+      (contains(github.event.pull_request.labels.*.name, 'run documentation') &&
+        (github.event.action != 'labeled' ||
+         github.event.label.name == 'run documentation' ||
+         github.event.label.name == 'documentation push preview'))
     uses: control-toolbox/CTActions/.github/workflows/documentation.yml@main
     with:
       use_ct_registry: true
diff --git a/docs/make.jl b/docs/make.jl
index 4208a1b4..eb971f3f 100644
--- a/docs/make.jl
+++ b/docs/make.jl
@@ -54,4 +54,10 @@ with_api_reference(src_dir, ext_dir) do api_pages
 end
 
 # ═══════════════════════════════════════════════════════════════════════════════
-deploydocs(; repo=repo_url * ".git", devbranch="main")
+# PR previews are opt-in: CTActions sets DOCUMENTER_PUSH_PREVIEW to "true" only on a
+# PR carrying the `documentation push preview` label.
+deploydocs(;
+    repo=repo_url * ".git",
+    devbranch="main",
+    push_preview=get(ENV, "DOCUMENTER_PUSH_PREVIEW", "false") == "true",
+)