diff --git a/.changeset/reference-utilize-inflections.md b/.changeset/reference-utilize-inflections.md
new file mode 100644
index 00000000..79a48845
--- /dev/null
+++ b/.changeset/reference-utilize-inflections.md
@@ -0,0 +1,5 @@
+---
+"@taskless/cli": patch
+---
+
+The `prefer-use-over-utilize` entry in `@taskless/cli/reference.json` now flags `utilized` and `utilization`, as its prompt asks, and carries a fail case for each. Previously the reference rule missed both, so a rule generated correctly from the prompt was graded against a reference that did not fire on those cases. The prompt now names the forms it expects. The corpus `version` is unchanged: the shape is the same, only the content of one entry moved.
diff --git a/packages/cli/assets/reference-vale/prefer-use-over-utilize.yml b/packages/cli/assets/reference-vale/prefer-use-over-utilize.yml
index b7206b10..28a46e5c 100644
--- a/packages/cli/assets/reference-vale/prefer-use-over-utilize.yml
+++ b/packages/cli/assets/reference-vale/prefer-use-over-utilize.yml
@@ -5,4 +5,6 @@ ignorecase: true
 swap:
   utilize: use
   utilizes: uses
+  utilized: used
   utilizing: using
+  utilization: use
diff --git a/packages/cli/assets/reference-vale/prompt.md b/packages/cli/assets/reference-vale/prompt.md
index 6ad7be39..a288acef 100644
--- a/packages/cli/assets/reference-vale/prompt.md
+++ b/packages/cli/assets/reference-vale/prompt.md
@@ -3,7 +3,8 @@ suggests "use" instead.
 
 "Utilize" is longer than "use" and means the same thing in nearly every
 sentence a reader will meet. It should match case-insensitively and cover the
-inflected forms.
+inflected forms ("utilizes", "utilized", "utilizing") as well as the noun
+"utilization".
 
 This is a prose rule. It applies to markdown, and it must not look at source
 code.
diff --git a/packages/cli/assets/reference-vale/tests/fail/utilization-noun/README.md b/packages/cli/assets/reference-vale/tests/fail/utilization-noun/README.md
new file mode 100644
index 00000000..3b0886d5
--- /dev/null
+++ b/packages/cli/assets/reference-vale/tests/fail/utilization-noun/README.md
@@ -0,0 +1,3 @@
+# Limits
+
+Memory utilization grows with the size of the batch.
diff --git a/packages/cli/assets/reference-vale/tests/fail/utilized-past/README.md b/packages/cli/assets/reference-vale/tests/fail/utilized-past/README.md
new file mode 100644
index 00000000..43d11d66
--- /dev/null
+++ b/packages/cli/assets/reference-vale/tests/fail/utilized-past/README.md
@@ -0,0 +1,3 @@
+# Migration
+
+We utilized the API to export the records.
diff --git a/packages/cli/assets/reference.json b/packages/cli/assets/reference.json
index 1b9ad03f..86b5c902 100644
--- a/packages/cli/assets/reference.json
+++ b/packages/cli/assets/reference.json
@@ -185,11 +185,11 @@
       "id": "prefer-use-over-utilize",
       "directory": ".taskless/rules/vale/prefer-use-over-utilize",
       "ruleFile": "prefer-use-over-utilize.yml",
-      "prompt": "Create a rule that flags the word \"utilize\" in markdown documentation and\nsuggests \"use\" instead.\n\n\"Utilize\" is longer than \"use\" and means the same thing in nearly every\nsentence a reader will meet. It should match case-insensitively and cover the\ninflected forms.\n\nThis is a prose rule. It applies to markdown, and it must not look at source\ncode.\n\nProse that should NOT be flagged:\n\n```md\nUse the installer to write the config file.\n```\n\nProse that SHOULD be flagged:\n\n```md\nUtilize the installer to write the config file.\n```\n",
+      "prompt": "Create a rule that flags the word \"utilize\" in markdown documentation and\nsuggests \"use\" instead.\n\n\"Utilize\" is longer than \"use\" and means the same thing in nearly every\nsentence a reader will meet. It should match case-insensitively and cover the\ninflected forms (\"utilizes\", \"utilized\", \"utilizing\") as well as the noun\n\"utilization\".\n\nThis is a prose rule. It applies to markdown, and it must not look at source\ncode.\n\nProse that should NOT be flagged:\n\n```md\nUse the installer to write the config file.\n```\n\nProse that SHOULD be flagged:\n\n```md\nUtilize the installer to write the config file.\n```\n",
       "rule": [
         {
           "path": "prefer-use-over-utilize.yml",
-          "content": "extends: substitution\nmessage: \"Prefer '%s' over '%s'.\"\nlevel: warning\nignorecase: true\nswap:\n  utilize: use\n  utilizes: uses\n  utilizing: using\n"
+          "content": "extends: substitution\nmessage: \"Prefer '%s' over '%s'.\"\nlevel: warning\nignorecase: true\nswap:\n  utilize: use\n  utilizes: uses\n  utilized: used\n  utilizing: using\n  utilization: use\n"
         },
         {
           "path": ".vale.ini",
@@ -206,6 +206,14 @@
           {
             "path": "tests/fail/utilize-in-prose/README.md",
             "content": "# Setup\n\nUtilize the installer to write the config file.\n"
+          },
+          {
+            "path": "tests/fail/utilized-past/README.md",
+            "content": "# Migration\n\nWe utilized the API to export the records.\n"
+          },
+          {
+            "path": "tests/fail/utilization-noun/README.md",
+            "content": "# Limits\n\nMemory utilization grows with the size of the batch.\n"
           }
         ],
         "cases": [
@@ -220,6 +228,18 @@
             "name": "utilize-in-prose",
             "path": "tests/fail/utilize-in-prose",
             "files": ["tests/fail/utilize-in-prose/README.md"]
+          },
+          {
+            "bucket": "fail",
+            "name": "utilized-past",
+            "path": "tests/fail/utilized-past",
+            "files": ["tests/fail/utilized-past/README.md"]
+          },
+          {
+            "bucket": "fail",
+            "name": "utilization-noun",
+            "path": "tests/fail/utilization-noun",
+            "files": ["tests/fail/utilization-noun/README.md"]
           }
         ]
       }
diff --git a/packages/cli/src/rules/corpus/manifest.ts b/packages/cli/src/rules/corpus/manifest.ts
index 7120270f..0a4b6a52 100644
--- a/packages/cli/src/rules/corpus/manifest.ts
+++ b/packages/cli/src/rules/corpus/manifest.ts
@@ -95,6 +95,8 @@ export const CORPUS_MANIFESTS: readonly CorpusManifest[] = [
     testPaths: [
       "tests/pass/use-in-prose/README.md",
       "tests/fail/utilize-in-prose/README.md",
+      "tests/fail/utilized-past/README.md",
+      "tests/fail/utilization-noun/README.md",
     ],
   },
   {
diff --git a/packages/cli/test/reference-verify.test.ts b/packages/cli/test/reference-verify.test.ts
new file mode 100644
index 00000000..029ead53
--- /dev/null
+++ b/packages/cli/test/reference-verify.test.ts
@@ -0,0 +1,69 @@
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { readFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { dirname, join } from "node:path";
+
+import { afterEach, describe, expect, it } from "vitest";
+
+import type { Reference } from "../src/rules/reference";
+import { findValeBinary } from "../src/rules/vale/binary";
+import { verifyValeRule } from "../src/rules/vale/verify";
+
+/**
+ * A reference rule passes its own held-out cases.
+ *
+ * Other teams grade a generated rule by running OUR rule against THEIR cases,
+ * so a reference narrower than its prompt marks a correct generation wrong.
+ * `prefer-use-over-utilize` shipped with a prompt asking for the inflected
+ * forms and a swap that lacked `utilized` (#591). Nothing ran the reference
+ * against its own cases, so nothing noticed. This stages the published entry
+ * exactly as a consumer would and verifies it.
+ */
+
+const referencePath = join(
+  import.meta.dirname,
+  "..",
+  "assets",
+  "reference.json"
+);
+
+const withVale = findValeBinary().path === undefined ? describe.skip : describe;
+
+const workspaces: string[] = [];
+afterEach(() => {
+  for (const workspace of workspaces.splice(0)) {
+    rmSync(workspace, { recursive: true, force: true });
+  }
+});
+
+/** Write a reference entry's rule and cases into a fresh project. */
+function stage(rule: Reference["rules"][number]): string {
+  const cwd = mkdtempSync(join(tmpdir(), "taskless-reference-"));
+  workspaces.push(cwd);
+  for (const file of [...rule.rule, ...rule.tests.files]) {
+    const target = join(cwd, rule.directory, file.path);
+    mkdirSync(dirname(target), { recursive: true });
+    writeFileSync(target, file.content);
+  }
+  return cwd;
+}
+
+withVale("the vale reference rule", () => {
+  it("fires on every fail case and stays quiet on every pass case", async () => {
+    const reference = JSON.parse(
+      await readFile(referencePath, "utf8")
+    ) as Reference;
+    const rule = reference.rules.find((entry) => entry.engine === "vale");
+    if (rule === undefined) throw new Error("reference has no vale rule");
+
+    const result = await verifyValeRule(stage(rule), rule.id);
+    if ("outcome" in result) {
+      throw new Error(
+        `expected a verification, got Vale ${result.outcome.status}`
+      );
+    }
+
+    expect(result.errors).toEqual([]);
+    expect(result.passed).toBe(true);
+  });
+});