test(config): fix cap-at-12 test to actually exercise the cap

tests/pilot/test_ai_review.py

@@ -1805,9 +1805,19 @@ def test_parse_repo_config_compare_against_drops_unknown_keys(capfd):
     assert "bogus-1" in captured.err
 
 
-def test_parse_repo_config_compare_against_caps_at_12():
-    raw_keys = ["claude-sonnet-5"] + [f"bogus-{i}" for i in range(20)]
-    cfg = parse_repo_config(json.dumps({"compare_against": raw_keys}))
-    # Only claude-sonnet-5 is valid; rest dropped; net result is 1 entry.
-    assert len(cfg["compare_against"]) == 1
+def test_parse_repo_config_compare_against_caps_at_12(monkeypatch):
+    """13+ valid keys must be truncated to the first 12; invalid keys are
+    dropped and do not count. Inject a 13th PRICES entry via monkeypatch so
+    the [:12] cap actually fires (cost_model.PRICES has exactly 12 keys
+    today, which would otherwise make the cap a no-op)."""
+    import cost_model as cm
+    monkeypatch.setitem(
+        cm.PRICES, "fake-model-13", cm.Price("Fake", 1.00, 2.00, 1.00, 0.10))
+    valid = list(cm.PRICES)  # 13 unique keys (12 real + 1 test-only)
+    raw = valid + ["bogus-extra"]  # 13 valid + 1 invalid
+    cfg = parse_repo_config(json.dumps({"compare_against": raw}))
+    assert len(cfg["compare_against"]) == 12
+    assert cfg["compare_against"] == valid[:12]
+    assert "fake-model-13" not in cfg["compare_against"]
+    assert "bogus-extra" not in cfg["compare_against"]