diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 487a0c3..9c01a9a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,3 +51,51 @@ jobs:
         run: bin/${{ matrix.workspace }}/build.sh
       - name: Test
         run: bin/${{ matrix.workspace }}/test.sh
+
+  # The rig's objectives, checked by the StepIt Editor's validator: the
+  # editor's own checks, then BehaviorTree.CPP loading every file, with the
+  # node models of the rig's behaviors, the library and the version the
+  # commander loads them with. A broken objective, e.g. an unknown node or
+  # port, or a missing subtree, fails here instead of on the robot.
+  objectives:
+    name: objectives
+    runs-on: ubuntu-24.04
+    container: ros:jazzy-ros-base
+    defaults:
+      run:
+        shell: bash
+    steps:
+      # nodejs runs the JavaScript actions below under act, which does not
+      # provide one in a container as GitHub does; setup-node installs the
+      # Node.js the editor uses.
+      - name: Install git, BehaviorTree.CPP and Node.js
+        run: apt-get update -qq && apt-get install -qq -y git ros-jazzy-behaviortree-cpp nodejs
+      - uses: actions/checkout@v4
+      # Only the editor's submodule, over HTTPS, as for the commander above.
+      - name: Check out the editor
+        run: |
+          git config --global --add safe.directory '*'
+          git config --global url.https://github.com/.insteadOf git@github.com:
+          git submodule update --init --depth 1 modules/stepit-editor
+      - uses: pnpm/action-setup@v4
+        with:
+          package_json_file: modules/stepit-editor/package.json
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: pnpm
+          cache-dependency-path: modules/stepit-editor/pnpm-lock.yaml
+      # Steps bypass the image's entrypoint, which would source ROS: the
+      # validator needs it to build, and to find the library when it runs.
+      - name: Build the validator
+        working-directory: modules/stepit-editor
+        run: |
+          source /opt/ros/jazzy/setup.bash
+          pnpm install --frozen-lockfile
+          cmake -S validator -B build/validator -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/opt/ros/jazzy
+          cmake --build build/validator --parallel
+      - name: Validate the objectives
+        working-directory: modules/stepit-editor
+        run: |
+          source /opt/ros/jazzy/setup.bash
+          pnpm run validate "$GITHUB_WORKSPACE/src/plugins/stepit_objectives/objectives"
diff --git a/CLAUDE.md b/CLAUDE.md
index 22bb1e6..802bddd 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -128,7 +128,9 @@ they reach the real robot: run them with `ROS_DOMAIN_ID=77`.
 `.github/workflows`: `ci.yml` builds and tests each workspace with the `bin/<workspace>` scripts in
 `ros:jazzy-ros-base` (the `plugins` job builds `modules/stepit-commander` first, checked out over
 HTTPS: `.gitmodules` lists SSH URLs); `ci-format.yml` runs pre-commit without the ament hooks;
-`ci-ros-lint.yml` runs those, per package. A new package must be added to the package list
+`ci-ros-lint.yml` runs those, per package. The `objectives` job of `ci.yml` builds the editor's native
+validator (submodule `stepit-editor`) against the ROS package of BehaviorTree.CPP and runs
+`validate` on `src/plugins/stepit_objectives/objectives`: a broken objective fails CI. A new package must be added to the package list
 of `ci-ros-lint.yml` and to the paths of the ament hooks in `.pre-commit-config.yaml`.
 
 ## Conventions
diff --git a/README.md b/README.md
index 0433dfd..7792838 100644
--- a/README.md
+++ b/README.md
@@ -480,7 +480,8 @@ only overrides:
   [`src/plugins`](src/plugins) holds the rig's behaviors and objectives, built
   on top of the commander's workspace;
 - the folder the editor opens: the rig's `src/plugins/stepit_objectives/objectives`,
-  instead of the editor's examples;
+  instead of the editor's examples, through `BEHAVIORS_DIR`, with this repo
+  mounted at `~/rig`;
 - a service of the rig's own, `stepit-macro`, on an image defined in
   [`docker/Dockerfile`](docker/Dockerfile): it mounts this repo at `~/ws`, and
   `/dev/input` from the host for the gamepad, and runs
@@ -508,14 +509,28 @@ modules:
 
 | Workflow | What it checks |
 |---|---|
-| [`ci.yml`](.github/workflows/ci.yml) | Builds and tests both workspaces, each in a job of its own, with the scripts of [`bin`](bin), in a `ros:jazzy-ros-base` container. The job of `src/plugins` first builds the commander's workspace from the `stepit-commander` submodule. |
+| [`ci.yml`](.github/workflows/ci.yml) | Builds and tests both workspaces, each in a job of its own, with the scripts of [`bin`](bin), in a `ros:jazzy-ros-base` container. The job of `src/plugins` first builds the commander's workspace from the `stepit-commander` submodule. A third job, `objectives`, validates the objectives with the StepIt Editor's validator, see below. |
 | [`ci-format.yml`](.github/workflows/ci-format.yml) | The pre-commit hooks that need no ROS: clang-format, black, codespell, and the checks of whitespace and files. |
 | [`ci-ros-lint.yml`](.github/workflows/ci-ros-lint.yml) | The ament linters of every package: copyright, lint_cmake and cpplint. |
 
 The build cannot use `industrial_ci`, as the modules do: it builds one
 workspace from the sources of the repo, and `src/plugins` is built on top of
-the commander's. CI checks out only the `stepit-commander` submodule, over
+the commander's. CI checks out only the `stepit-commander` and `stepit-editor` submodules, over
 HTTPS; the other modules have CI of their own.
 
+The `objectives` job runs the editor's validator, `validate`, on
+[`src/plugins/stepit_objectives/objectives`](src/plugins/stepit_objectives/objectives):
+the editor's own checks, then BehaviorTree.CPP loading every file with the node
+models of the rig's behaviors, built from the ROS package, the library and the
+version the commander loads them with. A broken objective, e.g. an unknown node
+or port, or a subtree that does not exist, fails the pull request instead of
+being refused by the commander on the robot. Run the same check by hand in the
+editor's container, where it validates that folder by default:
+
+```
+./docker/dock.sh shell stepit-editor
+validate.sh
+```
+
 The workflows run locally with [Nektos `act`](https://github.com/nektos/act),
 e.g. `act -W .github/workflows/ci.yml`.
diff --git a/docker/docker-compose.yml b/docker/docker-compose.yml
index 635dbfe..334aee2 100644
--- a/docker/docker-compose.yml
+++ b/docker/docker-compose.yml
@@ -112,10 +112,15 @@ services:
     init: true
     depends_on:
       - stepit-commander
+    # Edit the rig's objectives: the commander reads them again before each
+    # goal, so what the editor saves is what the Run button executes. The whole
+    # repo is mounted, not the folder alone: git deletes and recreates a folder
+    # when a branch it switches to lacks it, and a mount of the folder would
+    # then show the deleted one, empty, until the container is recreated.
     volumes:
-      # Edit the rig's objectives: the commander reads them again before each
-      # goal, so what the editor saves is what the Run button executes.
-      - ../src/plugins/stepit_objectives/objectives:/home/developer/behaviors
+      - ..:/home/developer/rig
+    environment:
+      BEHAVIORS_DIR: /home/developer/rig/src/plugins/stepit_objectives/objectives
     command: serve.sh
 
   # The camera driver, with its test page and the pictures on
diff --git a/modules/stepit-editor b/modules/stepit-editor
index 83a2a03..c4c6d7e 160000
--- a/modules/stepit-editor
+++ b/modules/stepit-editor
@@ -1 +1 @@
-Subproject commit 83a2a03cdc9e7d027b588c22aafab7b671d9721d
+Subproject commit c4c6d7e68dbb5340dda07fd169e16faf7fbe11b6