diff --git a/docs/metrics/maintainability-baseline.json b/docs/metrics/maintainability-baseline.json
index b4cf2516..5afe7f98 100644
--- a/docs/metrics/maintainability-baseline.json
+++ b/docs/metrics/maintainability-baseline.json
@@ -2,7 +2,7 @@
   "sourceDirectory": "src",
   "largeFileThresholdLoc": 350,
   "typeScriptFileCount": 338,
-  "locInSrc": 66207,
+  "locInSrc": 65869,
   "processExitReferenceCount": 152,
   "synchronousFsApiReferenceCount": 842,
   "largeFileCountOver350Loc": 52
diff --git a/docs/project-roadmap.md b/docs/project-roadmap.md
index 22d14fa5..aa518236 100644
--- a/docs/project-roadmap.md
+++ b/docs/project-roadmap.md
@@ -204,7 +204,7 @@ All criteria achieved:
 The check mode supports a maintainability regression gate that blocks increases in:
 - `process.exit` references
 - synchronous fs API references
-- files over 350 LOC
+- TypeScript files over 350 LOC
 
 ---
 
diff --git a/package.json b/package.json
index 69d4d772..e5dd6017 100644
--- a/package.json
+++ b/package.json
@@ -64,7 +64,7 @@
     "lint:fix": "eslint src/ --fix",
     "format": "prettier --write src/",
     "format:check": "prettier --check src/",
-    "validate": "bun run typecheck && bun run lint:fix && bun run format:check && bun run test:all",
+    "validate": "bun run typecheck && bun run lint:fix && bun run format:check && bun run maintainability:check && bun run test:all",
     "verify:bundle": "node scripts/verify-bundle.js",
     "maintainability:baseline": "node scripts/maintainability-baseline.js --out docs/metrics/maintainability-baseline.json",
     "maintainability:check": "node scripts/maintainability-baseline.js --check docs/metrics/maintainability-baseline.json",
diff --git a/scripts/maintainability-baseline.js b/scripts/maintainability-baseline.js
index 8258f945..00cd9f68 100644
--- a/scripts/maintainability-baseline.js
+++ b/scripts/maintainability-baseline.js
@@ -142,7 +142,12 @@ function countLines(content) {
   if (content.length === 0) {
     return 0;
   }
-  return content.split(/\r?\n/).length;
+
+  const lineBreakMatches = content.match(/\r\n|\n|\r/g);
+  const lineBreakCount = lineBreakMatches ? lineBreakMatches.length : 0;
+  const endsWithLineBreak = content.endsWith('\n') || content.endsWith('\r');
+
+  return endsWithLineBreak ? lineBreakCount : lineBreakCount + 1;
 }
 
 function countMatches(content, pattern) {