diff --git a/pyproject.toml b/pyproject.toml
index a871b79a..70f12410 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,10 @@ license = { text = "MIT" }
 dependencies = []
 
 [project.optional-dependencies]
-dev = ["pytest>=8.0"]
+dev = [
+    "pytest>=8.0",
+    "pyright>=1.1.409",
+]
 
 [build-system]
 requires = ["hatchling"]
@@ -19,3 +22,9 @@ packages = ["src/aelfrice"]
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
+
+[tool.pyright]
+include = ["src/aelfrice", "tests"]
+pythonVersion = "3.12"
+typeCheckingMode = "strict"
+reportMissingTypeStubs = false
diff --git a/uv.lock b/uv.lock
index 65c8248c..a48889b8 100644
--- a/uv.lock
+++ b/uv.lock
@@ -9,11 +9,15 @@ source = { editable = "." }
 
 [package.optional-dependencies]
 dev = [
+    { name = "pyright" },
     { name = "pytest" },
 ]
 
 [package.metadata]
-requires-dist = [{ name = "pytest", marker = "extra == 'dev'", specifier = ">=8.0" }]
+requires-dist = [
+    { name = "pyright", marker = "extra == 'dev'", specifier = ">=1.1.409" },
+    { name = "pytest", marker = "extra == 'dev'", specifier = ">=8.0" },
+]
 provides-extras = ["dev"]
 
 [[package]]
@@ -34,6 +38,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/cb/b1/3846dd7f199d53cb17f49cba7e651e9ce294d8497c8c150530ed11865bb8/iniconfig-2.3.0-py3-none-any.whl", hash = "sha256:f631c04d2c48c52b84d0d0549c99ff3859c98df65b3101406327ecc7d53fbf12", size = 7484, upload-time = "2025-10-18T21:55:41.639Z" },
 ]
 
+[[package]]
+name = "nodeenv"
+version = "1.10.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/24/bf/d1bda4f6168e0b2e9e5958945e01910052158313224ada5ce1fb2e1113b8/nodeenv-1.10.0.tar.gz", hash = "sha256:996c191ad80897d076bdfba80a41994c2b47c68e224c542b48feba42ba00f8bb", size = 55611, upload-time = "2025-12-20T14:08:54.006Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/88/b2/d0896bdcdc8d28a7fc5717c305f1a861c26e18c05047949fb371034d98bd/nodeenv-1.10.0-py2.py3-none-any.whl", hash = "sha256:5bb13e3eed2923615535339b3c620e76779af4cb4c6a90deccc9e36b274d3827", size = 23438, upload-time = "2025-12-20T14:08:52.782Z" },
+]
+
 [[package]]
 name = "packaging"
 version = "26.2"
@@ -61,6 +74,19 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/f4/7e/a72dd26f3b0f4f2bf1dd8923c85f7ceb43172af56d63c7383eb62b332364/pygments-2.20.0-py3-none-any.whl", hash = "sha256:81a9e26dd42fd28a23a2d169d86d7ac03b46e2f8b59ed4698fb4785f946d0176", size = 1231151, upload-time = "2026-03-29T13:29:30.038Z" },
 ]
 
+[[package]]
+name = "pyright"
+version = "1.1.409"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "nodeenv" },
+    { name = "typing-extensions" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/51/4e/3aa27f74211522dba7e9cbc3e74de779c6d4b654c54e50a4840623be8014/pyright-1.1.409.tar.gz", hash = "sha256:986ee05beca9e077c165758ad123667c679e050059a2546aa02473930394bc93", size = 4430434, upload-time = "2026-04-23T11:02:03.799Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/16/6b/330d8ebae582b30c2959a1ef4c3bc344ebde48c2ff0c3f113c4710735e11/pyright-1.1.409-py3-none-any.whl", hash = "sha256:aa3ea228cab90c845c7a60d28db7a844c04315356392aa09fafcee98c8c22fb3", size = 6438161, upload-time = "2026-04-23T11:02:01.309Z" },
+]
+
 [[package]]
 name = "pytest"
 version = "9.0.3"
@@ -76,3 +102,12 @@ sdist = { url = "https://files.pythonhosted.org/packages/7d/0d/549bd94f1a0a402dc
 wheels = [
     { url = "https://files.pythonhosted.org/packages/d4/24/a372aaf5c9b7208e7112038812994107bc65a84cd00e0354a88c2c77a617/pytest-9.0.3-py3-none-any.whl", hash = "sha256:2c5efc453d45394fdd706ade797c0a81091eccd1d6e4bccfcd476e2b8e0ab5d9", size = 375249, upload-time = "2026-04-07T17:16:16.13Z" },
 ]
+
+[[package]]
+name = "typing-extensions"
+version = "4.15.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/72/94/1a15dd82efb362ac84269196e94cf00f187f7ed21c242792a923cdb1c61f/typing_extensions-4.15.0.tar.gz", hash = "sha256:0cea48d173cc12fa28ecabc3b837ea3cf6f38c6d1136f85cbaaf598984861466", size = 109391, upload-time = "2025-08-25T13:49:26.313Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/18/67/36e9267722cc04a6b9f15c7f3441c2363321a3ea07da7ae0c0707beb2a9c/typing_extensions-4.15.0-py3-none-any.whl", hash = "sha256:f0fa19c6845758ab08074a0cfa8b7aecb71c999ca73d62883bc25cc018c4e548", size = 44614, upload-time = "2025-08-25T13:49:24.86Z" },
+]