diff --git a/.github/workflows/grog.yml b/.github/workflows/grog.yml
new file mode 100644
index 00000000..ec35bd01
--- /dev/null
+++ b/.github/workflows/grog.yml
@@ -0,0 +1,40 @@
+name: Grog (Wheel Install Smoke)
+
+on:
+  pull_request:
+    branches:
+      - master
+      - main
+  push:
+    branches:
+      - master
+      - main
+
+jobs:
+  grog:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install grog
+        shell: bash
+        run: |
+          curl -L https://grog.build/latest/grog-linux-amd64 -o grog
+          chmod +x grog
+          sudo mv grog /usr/local/bin/grog
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+        with:
+          enable-cache: true
+          cache-dependency-glob: "uv.lock"
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Run grog install smoke tests
+        run: grog test
diff --git a/.gitignore b/.gitignore
index d49cb08b..5fe20223 100644
--- a/.gitignore
+++ b/.gitignore
@@ -44,6 +44,13 @@ venv.bak/
 .coverage
 htmlcov/
 
+# Grog
+.grog/
+.grog-cache/
+
+# Hatch build hook intermediates
+.hatch-ext/
+
 # Jupyter Notebook
 .ipynb_checkpoints
 
diff --git a/BUILD.yaml b/BUILD.yaml
new file mode 100644
index 00000000..bfe66433
--- /dev/null
+++ b/BUILD.yaml
@@ -0,0 +1,54 @@
+targets:
+  - name: wheel_py
+    command: uv build --wheel --out-dir dist/grog/py --clear --no-create-gitignore
+    inputs:
+      - pyproject.toml
+      - hatch_build.py
+      - visdet/**
+      - README.md
+      - LICENSE
+      - MANIFEST.in
+    outputs:
+      - dir::dist/grog/py
+
+  - name: wheel_cpp
+    command: VISDET_BUILD_CPP_EXT=1 uv build --wheel --out-dir dist/grog/cpp --clear --no-create-gitignore
+    inputs:
+      - pyproject.toml
+      - hatch_build.py
+      - visdet/**
+      - README.md
+      - LICENSE
+      - MANIFEST.in
+    outputs:
+      - dir::dist/grog/cpp
+
+  - name: install_smoke_py_test
+    dependencies:
+      - :wheel_py
+    command: |
+      set -e
+      ROOT="$(pwd)"
+      rm -rf "$ROOT/.grog/venv-py"
+      uv venv "$ROOT/.grog/venv-py"
+      uv pip install --python "$ROOT/.grog/venv-py" "$ROOT/dist/grog/py"/*.whl
+      (cd /tmp && "$ROOT/.grog/venv-py/bin/python" -c "import visdet; from visdet._ext_demo import add, HAS_EXT; assert add(1,2)==3; assert HAS_EXT is False")
+      mkdir -p "$ROOT/.grog/out"
+      touch "$ROOT/.grog/out/install_smoke_py.ok"
+    outputs:
+      - .grog/out/install_smoke_py.ok
+
+  - name: install_smoke_cpp_test
+    dependencies:
+      - :wheel_cpp
+    command: |
+      set -e
+      ROOT="$(pwd)"
+      rm -rf "$ROOT/.grog/venv-cpp"
+      uv venv "$ROOT/.grog/venv-cpp"
+      uv pip install --python "$ROOT/.grog/venv-cpp" "$ROOT/dist/grog/cpp"/*.whl
+      (cd /tmp && "$ROOT/.grog/venv-cpp/bin/python" -c "import visdet; from visdet._ext_demo import add, HAS_EXT; assert add(2,3)==5; assert HAS_EXT is True")
+      mkdir -p "$ROOT/.grog/out"
+      touch "$ROOT/.grog/out/install_smoke_cpp.ok"
+    outputs:
+      - .grog/out/install_smoke_cpp.ok
diff --git a/grog.toml b/grog.toml
new file mode 100644
index 00000000..b630966b
--- /dev/null
+++ b/grog.toml
@@ -0,0 +1,2 @@
+# Grog configuration
+# Targets are defined in BUILD.yaml at repo root.
diff --git a/hatch_build.py b/hatch_build.py
new file mode 100644
index 00000000..0ca9a379
--- /dev/null
+++ b/hatch_build.py
@@ -0,0 +1,90 @@
+from __future__ import annotations
+
+import os
+import shlex
+import shutil
+import subprocess
+import sysconfig
+from pathlib import Path
+from typing import Any
+
+from hatchling.builders.hooks.plugin.interface import BuildHookInterface
+
+
+class CustomBuildHook(BuildHookInterface):
+    def initialize(self, version: str, build_data: dict[str, Any]) -> None:
+        # Keep installs working everywhere by default.
+        if os.environ.get("VISDET_BUILD_CPP_EXT", "0") != "1":
+            return
+
+        # Only build compiled artifacts for wheels.
+        if self.target_name != "wheel":
+            return
+
+        root = Path(self.root)
+        build_tmp = root / ".hatch-ext" / "cpp"
+        build_tmp.mkdir(parents=True, exist_ok=True)
+
+        src = build_tmp / "demo_ext.c"
+        src.write_text(
+            """
+#include <Python.h>
+
+static PyObject* demo_add(PyObject* self, PyObject* args) {
+    long a;
+    long b;
+    if (!PyArg_ParseTuple(args, \"ll\", &a, &b)) {
+        return NULL;
+    }
+    return PyLong_FromLong(a + b);
+}
+
+static PyMethodDef DemoMethods[] = {
+    {\"add\", demo_add, METH_VARARGS, \"Add two integers.\"},
+    {NULL, NULL, 0, NULL}
+};
+
+static struct PyModuleDef demomodule = {
+    PyModuleDef_HEAD_INIT,
+    \"_demo_ext\",
+    \"visdet demo C extension\",
+    -1,
+    DemoMethods
+};
+
+PyMODINIT_FUNC PyInit__demo_ext(void) {
+    return PyModule_Create(&demomodule);
+}
+""".lstrip(),
+            encoding="utf-8",
+        )
+
+        ext_suffix = sysconfig.get_config_var("EXT_SUFFIX")
+        if not ext_suffix:
+            self.app.display_warning("Could not determine EXT_SUFFIX; skipping C extension build")
+            return
+
+        out = build_tmp / f"_demo_ext{ext_suffix}"
+
+        include_dir = sysconfig.get_path("include")
+        ldshared = sysconfig.get_config_var("LDSHARED") or "cc -shared"
+        cflags = sysconfig.get_config_var("CFLAGS") or ""
+        cppflags = sysconfig.get_config_var("CPPFLAGS") or ""
+
+        cmd = (
+            shlex.split(ldshared)
+            + shlex.split(cflags)
+            + shlex.split(cppflags)
+            + [f"-I{include_dir}", "-o", str(out), str(src)]
+        )
+
+        self.app.display_info(f"Building C extension: {out.name}")
+        subprocess.check_call(cmd, cwd=str(root))
+
+        # Ensure hatchling includes the generated artifact in the wheel (without polluting the source tree).
+        build_data.setdefault("force_include", {})[str(out)] = f"visdet/_ext_demo/{out.name}"
+
+        # Avoid accidentally shipping .dSYM bundles (macOS).
+        dsym = out.with_suffix(out.suffix + ".dSYM")
+        if dsym.exists():
+            shutil.rmtree(dsym)
diff --git a/pyproject.toml b/pyproject.toml
index c8281cb7..db59cff2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -105,12 +105,25 @@ Documentation = "https://binitai.github.io/visdet/"
 # Exclude nested pyproject.toml that was part of old workspace structure
 exclude = [
     "visdet/pyproject.toml",
+    # Don't ship build intermediates
+    ".hatch-ext/**",
+    # Don't ship macOS debug bundles
+    "visdet/_ext_demo/*.dSYM/**",
+]
+
+# Hatchling has built-in ignores for directories like `dist/`, which clashes
+# with our internal module path `visdet/engine/dist/`. Force-include it.
+artifacts = [
+    "visdet/engine/dist/**",
 ]
 
 [tool.hatch.build.targets.wheel]
 # The package code is in visdet/ - tell hatchling where to find it
 packages = ["visdet"]
 
+[tool.hatch.build.hooks.custom]
+path = "hatch_build.py"
+
 [tool.ruff]
 line-length = 120
 target-version = "py310"
diff --git a/visdet/_ext_demo/__init__.py b/visdet/_ext_demo/__init__.py
new file mode 100644
index 00000000..fac25668
--- /dev/null
+++ b/visdet/_ext_demo/__init__.py
@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+import importlib
+import importlib.util
+
+_DEMO_EXT_SPEC = importlib.util.find_spec("visdet._ext_demo._demo_ext")
+HAS_EXT = _DEMO_EXT_SPEC is not None
+
+if HAS_EXT:
+    _demo_ext = importlib.import_module("visdet._ext_demo._demo_ext")
+else:
+    _demo_ext = None
+
+
+def add(a: int, b: int) -> int:
+    """Add two integers.
+
+    Uses the compiled extension when available, otherwise falls back to Python.
+    """
+
+    if _demo_ext is None:
+        return int(a) + int(b)
+
+    return int(_demo_ext.add(int(a), int(b)))