diff --git a/.markdownlint-cli2.jsonc b/.markdownlint-cli2.jsonc
new file mode 100644
index 0000000..7fbd1c4
--- /dev/null
+++ b/.markdownlint-cli2.jsonc
@@ -0,0 +1,14 @@
+{
+  "customRules": [".markdownlint-rules/one-sentence-per-line.mjs"],
+  "config": {
+    "default": true,
+    "heading-style": { "style": "atx" },
+    "ul-indent": { "indent": 2 },
+    "line-length": false,
+    "no-duplicate-heading": { "siblings_only": true },
+    "no-inline-html": {
+      "allowed_elements": ["br", "code", "details", "summary", "img", "picture", "source"]
+    },
+    "first-line-heading": true
+  }
+}
diff --git a/.markdownlint-rules/one-sentence-per-line.mjs b/.markdownlint-rules/one-sentence-per-line.mjs
new file mode 100644
index 0000000..afcf664
--- /dev/null
+++ b/.markdownlint-rules/one-sentence-per-line.mjs
@@ -0,0 +1,48 @@
+// @ts-check
+
+/**
+ * @typedef {object} ErrorInfo
+ * @property {number} lineNumber
+ * @property {string} [context]
+ * @property {string} [detail]
+ * @property {[number, number]} [range]
+ */
+
+/**
+ * @typedef {object} Params
+ * @property {string[]} lines
+ */
+
+/** @typedef {(error: ErrorInfo) => void} OnError */
+
+/**
+ * @typedef {object} Rule
+ * @property {string[]} names
+ * @property {string} description
+ * @property {string[]} tags
+ * @property {(params: Params, onError: OnError) => void} function
+ */
+
+/** @type {Rule} */
+export default {
+  names: ["one-sentence-per-line"],
+  description: "Each sentence must be on its own line",
+  tags: ["sentences"],
+  function: function (params, onError) {
+    let inFence = false;
+    params.lines.forEach((line, index) => {
+      if (/^```/.test(line)) {
+        inFence = !inFence;
+        return;
+      }
+      if (inFence) return;
+      // Skip headings, blank lines, HTML, table rows
+      if (/^(#|\s*[|<]|>|\s*$)/.test(line)) return;
+      // Strip list marker before checking
+      const text = line.replace(/^\s*(?:[-*+]|\d+\.)\s+/, "");
+      if (/[.!?]\s+[A-Z]/.test(text)) {
+        onError({ lineNumber: index + 1, context: text.trim() });
+      }
+    });
+  },
+};
diff --git a/.markdownlint.yml b/.markdownlint.yml
deleted file mode 100644
index f15868f..0000000
--- a/.markdownlint.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-default: true
-heading-style:
-  style: atx
-ul-indent:
-  indent: 2
-line-length: false
-no-duplicate-heading:
-  siblings_only: true
-no-inline-html:
-  allowed_elements:
-    - br
-    - details
-    - summary
-    - img
-    - picture
-    - source
-first-line-heading: true
diff --git a/README.md b/README.md
index 3ad99b0..567934a 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
 # <img height="30" src="assets/logo.svg" alt="Go Cuckoo, by `mvhutz`."> Go Cuckoo
 
-A hash table that uses cuckoo hashing to achieve a worst-case O(1) lookup time. Read more about it in [the package documentation](https://pkg.go.dev/git.maximhutz.com/tools/go-cuckoo).
+A hash table that uses cuckoo hashing to achieve a worst-case O(1) lookup time.
+Read more about it in [the package documentation][docs].
+
+[docs]: https://pkg.go.dev/git.maximhutz.com/tools/go-cuckoo