prose_checks: stop flagging "rather than" / "would rather" as weasel words

scripts/prose_checks.py

@@ -75,7 +75,10 @@
     r"somewhat",
     r"relatively",
     r"fairly",
-    r"rather",
+    # "rather" is a hedge only as an intensifier ("rather large"). "rather than"
+    # is a comparison and "would/I'd rather" a preference: 16 of 22 weasel hits
+    # in the 2026-09-20..23 Ralph runs were those two false positives.
+    r"(?<!would\s)(?<!'d\s)(?<!’d\s)rather(?!\s+than\b)",
     r"in\s+some\s+cases",
     r"in\s+many\s+cases",
     r"tends?\s+to",

tests/test_prose_checks_weasel.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+"""Tests for the weasel-word pattern in scripts/prose_checks.py.
+
+The negative cases come from the blog-review Ralph tuning corpus
+(2026-09-20..23), where 16 of 22 weasel-word hits were "rather than" or
+"would rather". Run with:
+
+    python3 -m unittest discover tests
+"""
+from __future__ import annotations
+
+import importlib.util
+import sys
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+SCRIPT = REPO_ROOT / "scripts" / "prose_checks.py"
+
+spec = importlib.util.spec_from_file_location("prose_checks", SCRIPT)
+prose_checks = importlib.util.module_from_spec(spec)
+sys.modules["prose_checks"] = prose_checks
+spec.loader.exec_module(prose_checks)
+
+
+def flagged(text: str) -> list[str]:
+    return [m.group(0).lower() for m in prose_checks.WEASEL_RE.finditer(text)]
+
+
+class RatherTests(unittest.TestCase):
+    def test_rather_than_is_a_comparison_not_a_hedge(self):
+        for s in [
+            "The watermark lives in token selection rather than hidden characters.",
+            "It provides likelihood rather than the deterministic guarantee.",
+            "The analogy is operational rather than cryptographic.",
+            "Rather than dispute that, I closed the ticket.",
+            "use minimal RBAC bindings rather\nthan relying on the default",
+        ]:
+            with self.subTest(s=s):
+                self.assertEqual(flagged(s), [])
+
+    def test_would_rather_is_a_preference_not_a_hedge(self):
+        for s in [
+            "the kind of artifact I would rather be evaluated on",
+            "I'd rather ship it today.",
+            "I’d rather ship it today.",
+        ]:
+            with self.subTest(s=s):
+                self.assertEqual(flagged(s), [])
+
+    def test_rather_as_intensifier_is_still_flagged(self):
+        for s in ["The blast radius is rather large.", "Rather surprisingly, it worked."]:
+            with self.subTest(s=s):
+                self.assertEqual(flagged(s), ["rather"])
+
+
+class OtherTermsUnchanged(unittest.TestCase):
+    def test_real_hedges_from_the_corpus_are_still_flagged(self):
+        self.assertEqual(flagged("In some cases, it's a quiet countdown."), ["in some cases"])
+        self.assertEqual(flagged("dispositions tend to fall into three buckets"), ["tend to"])
+        self.assertEqual(flagged("which could be weeks or months earlier"), ["could be"])
+
+
+if __name__ == "__main__":
+    unittest.main()