diff --git a/scanners/claude-md-linter.mjs b/scanners/claude-md-linter.mjs
index bfdceed..15043e2 100644
--- a/scanners/claude-md-linter.mjs
+++ b/scanners/claude-md-linter.mjs
@@ -59,15 +59,19 @@ export async function scan(targetPath, discovery) {
     const imports = findImports(content);
 
     // --- Length checks ---
+    // Raw line count is no longer an absolute adherence threshold: CC 2.1.169
+    // scales the "too long" warning by context window, and cache-prefix
+    // stability (not line count) is the dominant cost driver on large-context
+    // models. These are MEDIUM token-cost signals, not a HIGH adherence cliff.
     if (lines > MAX_ABSOLUTE_LINES) {
       findings.push(finding({
         scanner: SCANNER,
-        severity: SEVERITY.high,
+        severity: SEVERITY.medium,
         title: 'CLAUDE.md exceeds 500 lines',
-        description: `${file.relPath} has ${lines} lines. Files over 500 lines significantly reduce Claude's adherence to instructions.`,
+        description: `${file.relPath} has ${lines} lines. A file this size loads in full on every turn (token cost) and, on smaller-context models, can crowd out instructions. Large-context models tolerate longer files when the cache prefix stays stable — raw line count is no longer an absolute adherence threshold (CC 2.1.169 scales it by context window).`,
         file: file.absPath,
         evidence: `${lines} lines`,
-        recommendation: 'Split into @imports and .claude/rules/ files. Keep CLAUDE.md under 200 lines.',
+        recommendation: 'Split into @imports and .claude/rules/ files, and keep the top of CLAUDE.md byte-stable for cache hits (see token / cache-prefix findings). Under ~200 lines stays safest across models.',
         autoFixable: false,
       }));
     } else if (lines > MAX_RECOMMENDED_LINES) {
@@ -75,7 +79,7 @@ export async function scan(targetPath, discovery) {
         scanner: SCANNER,
         severity: SEVERITY.medium,
         title: 'CLAUDE.md exceeds recommended 200 lines',
-        description: `${file.relPath} has ${lines} lines. Best practice is under 200 lines for optimal adherence.`,
+        description: `${file.relPath} has ${lines} lines. Under ~200 lines is the safe default across models; larger is fine on large-context models when the cache prefix stays stable. A long file still costs tokens every turn.`,
         file: file.absPath,
         evidence: `${lines} lines`,
         recommendation: 'Consider using @imports or .claude/rules/ for detailed content.',
diff --git a/tests/scanners/claude-md-linter.test.mjs b/tests/scanners/claude-md-linter.test.mjs
index 9ef2ee8..2d8ceda 100644
--- a/tests/scanners/claude-md-linter.test.mjs
+++ b/tests/scanners/claude-md-linter.test.mjs
@@ -76,6 +76,59 @@ describe('CML scanner — broken project', () => {
   });
 });
 
+describe('CML scanner — broken project: 200-tier stays MEDIUM (regression lock)', () => {
+  let result;
+  beforeEach(async () => {
+    resetCounter();
+    const discovery = await discoverConfigFiles(resolve(FIXTURES, 'broken-project'));
+    result = await scan(resolve(FIXTURES, 'broken-project'), discovery);
+  });
+
+  it('the >200 length finding is MEDIUM', () => {
+    const f = result.findings.find(x => /exceeds recommended 200/.test(x.title || ''));
+    assert.ok(f, 'expected the 200-line recommendation finding');
+    assert.strictEqual(f.severity, 'medium');
+  });
+});
+
+describe('CML scanner — large cascade (>500 lines): reframed, not absolute-adherence HIGH', () => {
+  // large-cascade/CLAUDE.md is 1024 lines. CC 2.1.169 scales the "too long"
+  // threshold by context window, and the plugin's own
+  // configuration-best-practices.md:97 footnote says raw line count is a
+  // Sonnet-era heuristic superseded by cache-prefix stability. So the absolute
+  // HIGH@500 + "significantly reduce adherence" claim is now-wrong.
+  let result;
+  beforeEach(async () => {
+    resetCounter();
+    const discovery = await discoverConfigFiles(resolve(FIXTURES, 'large-cascade'));
+    result = await scan(resolve(FIXTURES, 'large-cascade'), discovery);
+  });
+
+  it('flags the >500 finding as MEDIUM, not HIGH', () => {
+    const f = result.findings.find(x => /exceeds 500/.test(x.title || ''));
+    assert.ok(f, 'expected the >500 length finding');
+    assert.strictEqual(f.severity, 'medium');
+  });
+
+  it('drops the absolute "significantly reduce adherence" claim', () => {
+    const f = result.findings.find(x => /exceeds 500/.test(x.title || ''));
+    assert.doesNotMatch(String(f?.description || ''), /significantly reduce/i);
+  });
+
+  it('reframes toward token cost / context window / cache-prefix', () => {
+    const f = result.findings.find(x => /exceeds 500/.test(x.title || ''));
+    assert.match(
+      `${f?.description || ''} ${f?.recommendation || ''}`,
+      /every turn|context window|cache/i,
+    );
+  });
+
+  it('produces no HIGH-severity length finding', () => {
+    const highLen = result.findings.filter(f => f.severity === 'high' && /exceeds/.test(f.title || ''));
+    assert.strictEqual(highLen.length, 0, `unexpected HIGH length finding: ${highLen.map(f => f.title).join(', ')}`);
+  });
+});
+
 describe('CML scanner — empty project', () => {
   let result;
   beforeEach(async () => {