diff --git a/.github/workflows/abi.yaml b/.github/workflows/abi.yaml
new file mode 100644
index 0000000000..fece42a7e9
--- /dev/null
+++ b/.github/workflows/abi.yaml
@@ -0,0 +1,77 @@
+# This workflow checks ABI compatibility of the shared libraries built from
+# this repository on every PR:
+#
+#   - librclcpp.so            (rclcpp)
+#   - librclcpp_action.so     (rclcpp_action)
+#   - libcomponent_manager.so (rclcpp_components)
+#   - librclcpp_lifecycle.so  (rclcpp_lifecycle)
+#
+# It uses the reusable ros2-abi-action workflow, which:
+#   1. resolves the ROS 2 distro from the PR's target branch (rolling/lyrical/kilted/jazzy/humble),
+#   2. builds all listed packages twice (once against the target branch, once
+#      against the PR head) with -g -Og so DWARF debug info is present; a single
+#      colcon invocation builds the union of the dependency closures exactly once,
+#   3. with build-mode: source, imports the distro's ros2.repos and builds
+#      against today's source tree instead of the released binaries; this is
+#      required for core repositories like rclcpp, whose dependencies (rcl,
+#      rmw, ...) are usually ahead of the released Debian packages. The
+#      incremental strategy starts from the nightly source-built underlay
+#      image (ros-abi:<distro>-source) and recompiles only what moved since,
+#   4. expands the soname glob and delegates the binary ABI diff to
+#      fujitatomoya/libabigail-action (abidiff), one job per library,
+#   5. applies REP-0009 policy automatically: released distros (humble/jazzy/kilted/lyrical)
+#      fail on an incompatible ABI break, rolling is advisory only,
+#   6. surfaces the verdict as a pass/fail check and uploads one report bundle
+#      (abidiff report + verdict.json) per library.
+#
+# The sticky PR comment, the "ABI compatible" / "ABI break" labels and the
+# "backport-<distro>" candidate labels are NOT posted from here
+# (publish: workflow-run). Most rclcpp pull requests come from forks, and on
+# pull_request events from a fork GitHub gives this workflow a read-only token
+# regardless of the permissions requested below, so any write to the PR would
+# fail. abi-report.yaml runs on workflow_run once this workflow completes and
+# publishes the comment and labels with a token that may write.
+#
+# Paired changes in other repositories (e.g. an rcl PR this PR depends on) are
+# declared by the PR author in the PR description and applied to the PR side
+# of the build:
+#
+#   Depends-On: ros2/rcl#1234
+#
+# See https://github.com/fujitatomoya/ros2-abi-action for details.
+name: abi
+
+on:
+  pull_request:
+    branches: [ "rolling", "lyrical", "kilted", "jazzy", "humble" ]
+
+  # Allows you to run this workflow manually from the Actions tab.
+  workflow_dispatch:
+
+jobs:
+  abi:
+    # Nothing is written to the pull request from this workflow; the report
+    # workflow holds the write permissions.
+    permissions:
+      contents: read
+    uses: fujitatomoya/ros2-abi-action/.github/workflows/check.yml@v1
+    with:
+      # Colcon package names to build (whitespace-separated); no single package
+      # depends on all the others, so list every package in this repository.
+      package: rclcpp rclcpp_action rclcpp_components rclcpp_lifecycle
+      # Shared libraries produced by the packages above. The glob matches all
+      # libraries in the install tree; tests are not built (BUILD_TESTING=OFF),
+      # so no test-only libraries are picked up.
+      soname: "lib*.so"
+      # rclcpp is a ROS 2 core repository: its dependencies are developed on
+      # source branches ahead of the released binaries, so build against the
+      # distro's ros2.repos source tree (nightly-cached, incremental) instead
+      # of the binary underlay.
+      build-mode: source
+      # auto -> distro derived from the PR target branch.
+      distro: auto
+      # auto -> REP-0009: strict on released distros, advisory on rolling.
+      policy: auto
+      # Leave the PR comment and labels to abi-report.yaml (workflow_run), so
+      # pull requests from forks get them too.
+      publish: workflow-run
diff --git a/rclcpp/include/rclcpp/node.hpp b/rclcpp/include/rclcpp/node.hpp
index 35863abba4..86780b4b6c 100644
--- a/rclcpp/include/rclcpp/node.hpp
+++ b/rclcpp/include/rclcpp/node.hpp
@@ -76,6 +76,7 @@ namespace rclcpp
 {
 
 /// Node is the single point of entry for creating publishers and subscribers.
+/// ABI test: this comment line has no effect on the compiled library.
 class Node : public std::enable_shared_from_this<Node>
 {
 public: