diff --git a/scripts/check_model_freshness.py b/scripts/check_model_freshness.py
index 5d32c309..39cc679a 100644
--- a/scripts/check_model_freshness.py
+++ b/scripts/check_model_freshness.py
@@ -35,7 +35,9 @@ import os
 import re
 import sys
 
-EXCLUDED_DIRS = {
+# Excludes both directory names (pruned during walk) and individual filenames
+# (e.g. CHANGELOG.md) — membership is checked against dirnames AND filenames.
+EXCLUDED_NAMES = {
     ".git", ".codex", ".gemini", ".hermes", ".vibe", "node_modules",
     "docs",   # generated mirror; fix the source instead
     "audit",  # audit records quote stale IDs on purpose, that is their job
@@ -157,9 +159,9 @@ def scan_file(path, repo_root, allowlist):
 def collect(repo_root):
     targets = []
     for dirpath, dirnames, filenames in os.walk(repo_root):
-        dirnames[:] = [d for d in dirnames if d not in EXCLUDED_DIRS]
+        dirnames[:] = [d for d in dirnames if d not in EXCLUDED_NAMES]
         for fn in filenames:
-            if fn in EXCLUDED_DIRS or fn in SELF_FILES:
+            if fn in EXCLUDED_NAMES or fn in SELF_FILES:
                 continue
             if fn.endswith(SCAN_EXTENSIONS):
                 targets.append(os.path.join(dirpath, fn))
diff --git a/scripts/derive_counters.py b/scripts/derive_counters.py
index cb8b2754..c87060eb 100644
--- a/scripts/derive_counters.py
+++ b/scripts/derive_counters.py
@@ -3,7 +3,7 @@
 
 Walks the canonical tree (excluding sync copies, docs site, audit workspace,
 and VCS/CI internals) and derives the headline numbers that README.md,
-CLAUDE.md, and .claude-plugin/marketplace.json claim:
+CLAUDE.md, marketplace.json, mkdocs.yml, and .codex-plugin/plugin.json claim:
 
   skills              count of SKILL.md files
   plugins_on_disk     count of **/.claude-plugin/plugin.json manifests
@@ -19,11 +19,13 @@ Modes:
   (default)   print a human-readable table
   --json      print the derived counters as JSON
   --check     exit 1 listing mismatches if the headline counters claimed in
-              README.md, root CLAUDE.md ("Current Scope" line), and
-              marketplace.json metadata.description disagree with derived
-              values. Also validates the README "Skills Overview" per-domain
-              table: every domain row's count must equal the SKILL.md count in
-              its linked folder, and every on-disk domain must have a row. CI gate G3.
+              README.md, root CLAUDE.md ("Current Scope" / "Status:" lines),
+              marketplace.json metadata.description, mkdocs.yml
+              site_description, or .codex-plugin/plugin.json descriptions
+              disagree with derived values. Also validates the README
+              "Skills Overview" per-domain table: every domain row's count
+              must equal the SKILL.md count in its linked folder, and every
+              on-disk domain must have a row. CI gate G3.
 
 Stdlib only. No writes ever.
 """
@@ -360,7 +362,7 @@ def main() -> int:
     parser.add_argument(
         "--check",
         action="store_true",
-        help="exit 1 if README.md / CLAUDE.md / marketplace.json claims drift from derived values",
+        help="exit 1 if claims in README.md / CLAUDE.md / marketplace.json / mkdocs.yml / .codex-plugin drift from derived values",
     )
     args = parser.parse_args()