diff --git a/.gitignore b/.gitignore
index 2149e79f..f698e90d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -112,3 +112,6 @@ src/*/_setuptools_scm_version.py
 
 # Nix
 result
+
+# Vale styles downloaded by ``vale sync``
+styles/
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7a35ad16..fdc9b955 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -309,6 +309,36 @@ repos:
           - *uv_version
         stages: [pre-commit]
 
+      # Vale enforces prose style rules, such as banning em dashes, in
+      # reStructuredText files.
+      # The rules come from the ``ClearProse`` package pinned in ``.vale.ini``,
+      # which ``vale sync`` downloads into the (gitignored) ``styles``
+      # directory.
+      # Vale needs ``rst2html`` from Docutils on the ``PATH`` to parse
+      # reStructuredText.
+      # ``vale sync`` also runs when ``.vale.ini`` changes, so a package
+      # bump takes effect without waiting for the next reStructuredText
+      # change.
+      - id: vale-sync
+        name: vale sync
+        entry: uv run --extra=dev vale sync
+        language: python
+        pass_filenames: false
+        files: (\.rst$|^\.vale\.ini$)
+        additional_dependencies:
+          - *uv_version
+        stages: [pre-commit]
+
+      - id: vale
+        name: vale
+        entry: uv run --extra=dev vale
+        language: python
+        types_or: [rst]
+        require_serial: true
+        additional_dependencies:
+          - *uv_version
+        stages: [pre-commit]
+
       - id: doc8
         name: doc8
         entry: uv run --extra=dev -m doc8
diff --git a/.vale.ini b/.vale.ini
new file mode 100644
index 00000000..8e3f9f74
--- /dev/null
+++ b/.vale.ini
@@ -0,0 +1,7 @@
+StylesPath = styles
+MinAlertLevel = error
+
+Packages = https://github.com/adamtheturtle/vale-style-clear-prose/releases/download/v1.1.0/ClearProse.zip
+
+[*.rst]
+BasedOnStyles = ClearProse
diff --git a/pyproject.toml b/pyproject.toml
index 5ee826d3..0f4e9d5e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -88,6 +88,7 @@ optional-dependencies.dev = [
     "towncrier==25.8.0",
     "ty==0.0.65",
     "types-pyyaml==6.0.12.20260724",
+    "vale==3.13.0.0",
     "vulture==2.16",
     "vws-python-mock==2026.2.22.3",
     "vws-test-fixtures==2023.3.5",
@@ -297,6 +298,7 @@ ignore = [
     ".git_archival.txt",
     ".pre-commit-config.yaml",
     ".prettierrc",
+    ".vale.ini",
     ".yamlfmt",
     "bin",
     "bin/*",
diff --git a/uv.lock b/uv.lock
index 291d9ee8..658c9048 100644
--- a/uv.lock
+++ b/uv.lock
@@ -2410,6 +2410,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/7f/3e/5db95bcf282c52709639744ca2a8b149baccf648e39c8cc87553df9eae0c/urllib3-2.7.0-py3-none-any.whl", hash = "sha256:9fb4c81ebbb1ce9531cce37674bbc6f1360472bc18ca9a553ede278ef7276897", size = 131087, upload-time = "2026-05-07T16:13:17.151Z" },
 ]
 
+[[package]]
+name = "vale"
+version = "3.13.0.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/0d/0d/6ebd7d020135888cc4d35290737871986ceabf176ba5e44827294429283a/vale-3.13.0.0.tar.gz", hash = "sha256:9c2482ecab515e58aa8d7e1a09f3d44ed674a07502786e22ff60c9d4fdc8493b", size = 5340, upload-time = "2025-10-28T13:20:41.459Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/e0/05/92b9e4d3e3cb424d2a1aa6e070ee838f15f6739a90b06964156a24fe49ce/vale-3.13.0.0-py3-none-any.whl", hash = "sha256:b565197a5f6e430af7ccc59204e75c6067bbd091a0073d700efdd0fba21873ed", size = 5944, upload-time = "2025-10-28T13:20:40.35Z" },
+]
+
 [[package]]
 name = "vcs-versioning"
 version = "2.1.2"
@@ -2496,6 +2505,7 @@ dev = [
     { name = "towncrier" },
     { name = "ty" },
     { name = "types-pyyaml" },
+    { name = "vale" },
     { name = "vulture" },
     { name = "vws-python-mock" },
     { name = "vws-test-fixtures" },
@@ -2558,6 +2568,7 @@ requires-dist = [
     { name = "towncrier", marker = "extra == 'release'", specifier = "==25.8.0" },
     { name = "ty", marker = "extra == 'dev'", specifier = "==0.0.65" },
     { name = "types-pyyaml", marker = "extra == 'dev'", specifier = "==6.0.12.20260724" },
+    { name = "vale", marker = "extra == 'dev'", specifier = "==3.13.0.0" },
     { name = "vulture", marker = "extra == 'dev'", specifier = "==2.16" },
     { name = "vws-python", specifier = "==2026.2.25.1" },
     { name = "vws-python-mock", marker = "extra == 'dev'", specifier = "==2026.2.22.3" },