UCL-ARC · paddyroddy · Jun 12, 2026 · Jun 12, 2026 · Jun 12, 2026 · Jun 12, 2026
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
@@ -23,14 +23,14 @@ repos:
     rev: v0.24.4
     hooks:
       - id: toml-sort-fix
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.20.2
+  - repo: https://github.com/astral-sh/ty-pre-commit
+    rev: v0.0.49
     hooks:
-      - id: mypy
+      - id: ty
         args:
-          - --config-file=pyproject.toml
-        additional_dependencies:
-          - pytest
+          - --group=typechecking
+          - --isolated
+          - --no-default-groups
   - repo: https://github.com/rbubley/mirrors-prettier
     rev: v3.8.3
     hooks:

diff --git a/.prekignore b/.prekignore
@@ -0,0 +1 @@
+tests/data/
diff --git a/docs/pages/libraries/jupyter-notebooks.md b/docs/pages/libraries/jupyter-notebooks.md
@@ -32,7 +32,7 @@ more reliably than [black] via [nbQA].
 | Name             | Short description                                                                |                      🚦                      |
 | ---------------- | -------------------------------------------------------------------------------- | :------------------------------------------: |
 | `black[jupyter]` | (also `black-jupyter`) [black] with the optional Jupyter extension.              | <span class="label label-green">Best</span>  |
-| [nbQA]           | Recommended for all other linters ([ruff], [isort]) and [mypy].                  | <span class="label label-green">Best</span>  |
+| [nbQA]           | Recommended for all other linters ([ruff], [isort]) and [ty].                    | <span class="label label-green">Best</span>  |
 | [pre-commit]     | Has cell output cleanup hooks (if desired). Also found to work well with [nbQA]. | <span class="label label-green">Best</span>  |
 | `nbqa black`     | [black] via [nbQA].                                                              | <span class="label label-yellow">Good</span> |
 
@@ -48,7 +48,7 @@ more reliably than [black] via [nbQA].
 [nbQA]: https://nbqa.readthedocs.io/en/latest/index.html
 [isort]: https://pycqa.github.io/isort
 [ruff]: https://github.com/charliermarsh/ruff
-[mypy]: https://mypy.readthedocs.io/en/stable
+[ty]: https://docs.astral.sh/ty/
 [pre-commit]: https://github.com/kynan/nbstripout
 [jupytext]: https://jupytext.readthedocs.io/en/stable/
 

diff --git a/docs/pages/linting.md b/docs/pages/linting.md
@@ -29,9 +29,10 @@ for some of these.
 
 ### Type checking
 
-| Name                                           | Short description                                                             |                     🚦                      |
-| ---------------------------------------------- | ----------------------------------------------------------------------------- | :-----------------------------------------: |
-| [mypy](https://mypy.readthedocs.io/en/stable/) | Static type checker, won't fail if no typing but will if typing is incorrect. | <span class="label label-green">Best</span> |
+| Name                                           | Short description                                                             |                      🚦                      |
+| ---------------------------------------------- | ----------------------------------------------------------------------------- | :------------------------------------------: |
+| [ty](https://docs.astral.sh/ty/)               | Static type checker, fast and rapidly developing.                             | <span class="label label-green">Best</span>  |
+| [mypy](https://mypy.readthedocs.io/en/stable/) | Static type checker, won't fail if no typing but will if typing is incorrect. | <span class="label label-yellow">Good</span> |
 
 ### Dependency checking
 

diff --git a/docs/pages/tutorial.md b/docs/pages/tutorial.md
@@ -400,10 +400,10 @@

 The package is set-up to use [pre-commit](https://pre-commit.com/), a framework for running [Git hook scripts](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks) on each commit to the repository.

 There is a `.pre-commit-config.yaml` configuration file which you can take a look at.
 With this setup `pre-commit` will run a series of fast linters, checks and formatters on the repository on every commit.
 
-The main tools we recommend are [ruff](https://docs.astral.sh/ruff/), [mypy](https://mypy.readthedocs.io/en/stable/) and [prettier](https://prettier.io/).
+The main tools we recommend are [ruff](https://docs.astral.sh/ruff/), [ty](https://docs.astral.sh/ty/) and [prettier](https://prettier.io/).
 These Git hook scripts can installed locally by running
 
 ```sh

diff --git a/pyproject.toml b/pyproject.toml
@@ -1,3 +1,9 @@
+[dependency-groups]
+typechecking = [
+    "pytest",
+    "pytest-venv",
+]
+
 [tool.pytest.ini_options]
 addopts = [
     "--color=yes",

diff --git a/tests/data/test_package_generation/.pre-commit-config.yaml b/tests/data/test_package_generation/.pre-commit-config.yaml
@@ -18,10 +18,14 @@ repos:
     rev: v0.24.4
     hooks:
       - id: toml-sort-fix
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.20.2
+  - repo: https://github.com/astral-sh/ty-pre-commit
+    rev: v0.0.49
     hooks:
-      - id: mypy
+      - id: ty
+        args:
+          - --group=typechecking
+          - --isolated
+          - --no-default-groups
   - repo: https://github.com/rbubley/mirrors-prettier
     rev: v3.8.3
     hooks:

diff --git a/tests/data/test_package_generation/pyproject.toml b/tests/data/test_package_generation/pyproject.toml
@@ -8,11 +8,11 @@ requires = [
 [dependency-groups]
 dev = [
     "build",
-    "mypy",
     "pre-commit",
     "ruff",
     "tox",
     "twine",
+    "ty",
 ]
 docs = [
     "mkdocs-include-markdown-plugin",
@@ -25,6 +25,9 @@ test = [
     "pytest",
     "pytest-cov",
 ]
+typechecking = [
+    "pytest",
+]
 
 [project]
 authors = [
@@ -67,9 +70,6 @@ paths.source = [
     ".tox*/*/lib/python*/site-packages",
 ]
 
-[tool.mypy]
-explicit_package_bases = true
-
 [tool.pytest.ini_options]
 addopts = [
     "--color=yes",
@@ -148,3 +148,7 @@ gh.python."3.11" = ["py311"]
 gh.python."3.12" = ["py312"]
 gh.python."3.13" = ["py313"]
 gh.python."3.14" = ["py314"]
+
+[tool.ty]
+analysis.respect-type-ignore-comments = false
+terminal.error-on-warning = true
diff --git a/tests/data/test_package_generation/src/cookiecutter_test/__init__.py b/tests/data/test_package_generation/src/cookiecutter_test/__init__.py
@@ -1,6 +1,6 @@
 """cookiecutter_test package."""
 
-from ._version import __version__  # noqa: F401
+from ._version import __version__  # noqa: F401  # ty: ignore[unresolved-import]
 
 
 def example_function(argument: str, keyword_argument: str = "default") -> str:

diff --git a/{{cookiecutter.project_slug}}/.pre-commit-config.yaml b/{{cookiecutter.project_slug}}/.pre-commit-config.yaml
@@ -18,10 +18,14 @@ repos:
     rev: v0.24.4
     hooks:
       - id: toml-sort-fix
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.20.2
+  - repo: https://github.com/astral-sh/ty-pre-commit
+    rev: v0.0.49
     hooks:
-      - id: mypy
+      - id: ty
+        args:
+          - --group=typechecking
+          - --isolated
+          - --no-default-groups
   - repo: https://github.com/rbubley/mirrors-prettier
     rev: v3.8.3
     hooks:

diff --git a/{{cookiecutter.project_slug}}/pyproject.toml b/{{cookiecutter.project_slug}}/pyproject.toml
@@ -8,11 +8,11 @@ requires = [
 [dependency-groups]
 dev = [
     "build",
-    "mypy",
     "pre-commit",
     "ruff",
     "tox",
     "twine",
+    "ty",
 ]
 docs = [
     "mkdocs-include-markdown-plugin",
@@ -25,6 +25,9 @@ test = [
     "pytest",
     "pytest-cov",
 ]
+typechecking = [
+    "pytest",
+]
 
 [project]
 authors = [
@@ -69,9 +72,6 @@ paths.source = [
     ".tox*/*/lib/python*/site-packages",
 ]
 
-[tool.mypy]
-explicit_package_bases = true
-
 [tool.pytest.ini_options]
 addopts = [
     "--color=yes",
@@ -154,3 +154,7 @@ env.docs = {commands = [
 ) %}
 gh.python."3.{{python_version}}" = ["py3{{python_version}}"]
 {%- endfor %}
+
+[tool.ty]
+analysis.respect-type-ignore-comments = false
+terminal.error-on-warning = true
diff --git a/{{cookiecutter.project_slug}}/src/{{cookiecutter.package_name}}/__init__.py b/{{cookiecutter.project_slug}}/src/{{cookiecutter.package_name}}/__init__.py
@@ -1,6 +1,6 @@
 """{{cookiecutter.package_name}} package."""
 
-from ._version import __version__  # noqa: F401
+from ._version import __version__  # noqa: F401 # ty: ignore[unresolved-import]
 
 
 def example_function(argument: str, keyword_argument: str = "default") -> str:
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		tests/data/
paddyroddy Jun 12, 2026 Copy link Copy Markdown Member Author Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. I am using https://github.com/j178/prek in favour of `pre-commit` locally. I found that running on the top level was running the hooks in `tests/data/test_package_generation` which was causing bugs.