diff --git a/scripts/coverage/diff.mjs b/scripts/coverage/diff.mjs
index 732e472..2d9aaf7 100644
--- a/scripts/coverage/diff.mjs
+++ b/scripts/coverage/diff.mjs
@@ -68,6 +68,14 @@ const ALLOWED_GLOBS = [
   // Tooling packages that don't generate a vitest lcov (no @vitest/coverage-v8)
   /^packages\/core-testing\//,
   /^packages\/core-eslint\//,
+  // App packages (web-next, web-tanstack, cms) do not configure
+  // @vitest/coverage-v8, so their source files never appear in the merged lcov.
+  /^apps\//,
+  // core-shared Sentry client init files — explicitly excluded from per-package
+  // vitest coverage in core-shared/vitest.config.ts ("Sentry client init —
+  // browser/node SDK init, tested in apps"); they have test files but coverage
+  // is excluded by design (browser SDK calls, not unit-testable in isolation).
+  /\/instrumentation\/sentry\//,
   // Pure type-alias / interface files (no executable code)
   /\.d\.ts$/, // ambient declaration files — no runtime code by definition
   /\.interface\.ts$/,
diff --git a/scripts/coverage/diff.test.mjs b/scripts/coverage/diff.test.mjs
index 0ca2193..534735b 100644
--- a/scripts/coverage/diff.test.mjs
+++ b/scripts/coverage/diff.test.mjs
@@ -243,6 +243,44 @@ describe("computeDiffCoverage", () => {
     assert.equal(result.summary.filesChanged, 2);
   });
 
+  test("skips apps/ files (app packages don't configure @vitest/coverage-v8)", () => {
+    const lcov = parseLcov(lcovText);
+    const diff = new Map([
+      // web-next and web-tanstack have no @vitest/coverage-v8 — never in lcov
+      ["apps/web-next/instrumentation-client.ts", new Set([1, 2, 3, 4, 5, 6])],
+      ["apps/web-next/middleware.ts", new Set([1, 2, 3, 4, 5])],
+      ["apps/web-next/src/app/layout.tsx", new Set([1, 2, 3])],
+      [
+        "apps/web-tanstack/src/instrumentation-client.ts",
+        new Set([1, 2, 3, 4, 5]),
+      ],
+      ["apps/web-tanstack/app.config.ts", new Set([1, 2, 3])],
+    ]);
+    const result = computeDiffCoverage(diff, lcov);
+    assert.equal(result.status, "pass");
+    assert.equal(result.summary.filesGated, 0);
+    assert.equal(result.summary.filesChanged, 5);
+  });
+
+  test("skips core-shared sentry init files (excluded from vitest coverage by design)", () => {
+    const lcov = parseLcov(lcovText);
+    const diff = new Map([
+      // core-shared/vitest.config.ts excludes src/instrumentation/sentry/**
+      [
+        "packages/core-shared/src/instrumentation/sentry/init-client.ts",
+        new Set([1, 2, 3, 4, 5]),
+      ],
+      [
+        "packages/core-shared/src/instrumentation/sentry/init-client-react.ts",
+        new Set([1, 2, 3, 4, 5]),
+      ],
+    ]);
+    const result = computeDiffCoverage(diff, lcov);
+    assert.equal(result.status, "pass");
+    assert.equal(result.summary.filesGated, 0);
+    assert.equal(result.summary.filesChanged, 2);
+  });
+
   test("end-to-end fixture: mixed pass/fail/skip/no-data", () => {
     const lcov = parseLcov(lcovText);
     const diff = parseGitDiff(diffText);