diff --git a/tests/test_check_explainer_count.py b/tests/test_check_explainer_count.py
index d15ebe86..087e5c69 100644
--- a/tests/test_check_explainer_count.py
+++ b/tests/test_check_explainer_count.py
@@ -1,4 +1,5 @@
 import importlib
+import sys
 from pathlib import Path
 
 check = importlib.import_module("scripts.check_explainer_count")
@@ -45,3 +46,99 @@ def test_main_fails_and_names_the_missing_slug(tmp_path, monkeypatch, capsys):
     monkeypatch.setattr(check, "CHECKS", [])
     assert check.main() == 1
     assert "README.md: does not list new-one" in capsys.readouterr().err
+
+
+def _count_site(root: Path, count: int = 2) -> Path:
+    root.mkdir()
+    explainers = root / "explainers"
+    explainers.mkdir()
+    for slug in ("one", "two"):
+        (explainers / f"{slug}.md").write_text("# x\n", encoding="utf-8")
+    (root / "README.md").write_text(
+        f"Show all {count} explainers\n"
+        f"Explainers Published | {count}\n"
+        f"{count} short, plain-language write-ups\n"
+        "- [one](explainers/one.md)\n"
+        "- [two](explainers/two.html)\n",
+        encoding="utf-8",
+    )
+    (root / "CONTRIBUTORS.md").write_text(
+        f"the bulk of the {count} explainers\n", encoding="utf-8"
+    )
+    (root / "METRICS.md").write_text(
+        f"Explainers-{count}-blueviolet\n| Explainers | {count} |\n",
+        encoding="utf-8",
+    )
+    (root / "ROADMAP.md").write_text(
+        f"{count} explainers published\n", encoding="utf-8"
+    )
+    (root / "llms.txt").write_text(
+        "- /explainers/one.html\n- /explainers/two.html\n", encoding="utf-8"
+    )
+    return root
+
+
+def _run_main(root: Path, monkeypatch, args=()):
+    monkeypatch.setattr(check, "ROOT", root)
+    monkeypatch.setattr(check, "EXPLAINERS_DIR", root / "explainers")
+    monkeypatch.setattr(sys, "argv", ["check_explainer_count.py", *args])
+    return check.main()
+
+
+def test_main_passes_when_all_count_patterns_and_listings_match(
+    tmp_path, monkeypatch, capsys
+):
+    root = _count_site(tmp_path / "site")
+
+    assert _run_main(root, monkeypatch) == 0
+
+    assert "all 7 explainer-count mentions match" in capsys.readouterr().out
+
+
+def test_main_reports_stale_counts_and_both_missing_listings(
+    tmp_path, monkeypatch, capsys
+):
+    root = _count_site(tmp_path / "site", count=1)
+    (root / "README.md").write_text("Show all 1 explainers\n", encoding="utf-8")
+    (root / "llms.txt").write_text("", encoding="utf-8")
+
+    assert _run_main(root, monkeypatch) == 1
+
+    captured = capsys.readouterr()
+    assert "says 1 explainers, but explainers/*.md has 2" in captured.err
+    assert "README.md: does not list one, two" in captured.err
+    assert "llms.txt: does not list one, two" in captured.err
+    assert "--fix" in captured.err
+
+
+def test_main_fix_rewrites_only_count_mentions(tmp_path, monkeypatch, capsys):
+    root = _count_site(tmp_path / "site", count=1)
+    before = {
+        name: (root / name).read_text(encoding="utf-8")
+        for name in ("README.md", "CONTRIBUTORS.md", "METRICS.md", "ROADMAP.md")
+    }
+
+    assert _run_main(root, monkeypatch, ["--fix"]) == 0
+
+    captured = capsys.readouterr()
+    assert "Corrected 7 explainer-count mention(s)" in captured.out
+    assert "README.md: 1 -> 2" in captured.out
+    for name, text in before.items():
+        fixed = (root / name).read_text(encoding="utf-8")
+        assert fixed == text.replace("1", "2")
+    assert "up to date" not in captured.out
+
+
+def test_main_fix_reports_missing_pattern_and_listing_without_suggesting_fix(
+    tmp_path, monkeypatch, capsys
+):
+    root = _count_site(tmp_path / "site")
+    (root / "METRICS.md").write_text("badge only\n", encoding="utf-8")
+    (root / "README.md").write_text("Show all 2 explainers\n", encoding="utf-8")
+
+    assert _run_main(root, monkeypatch, ["--fix"]) == 1
+
+    captured = capsys.readouterr()
+    assert "expected pattern not found" in captured.err
+    assert "README.md: does not list one, two" in captured.err
+    assert "Run 'python3 scripts/check_explainer_count.py --fix'" not in captured.err