diff --git a/packages/cli/src/commands/media-treatment.test.ts b/packages/cli/src/commands/media-treatment.test.ts
index bbcecbaf5..d525a6c64 100644
--- a/packages/cli/src/commands/media-treatment.test.ts
+++ b/packages/cli/src/commands/media-treatment.test.ts
@@ -1,6 +1,6 @@
 import { mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
-import { join } from "node:path";
+import { basename, join } from "node:path";
 import { runCommand } from "citty";
 import { describe, expect, it, vi } from "vitest";
 import {
@@ -211,11 +211,13 @@ describe("applyMediaTreatmentToHtml", () => {
 
   it("resolves nested composition media through the shared project-root contract", () => {
     const project = mkdtempSync(join(tmpdir(), "hf-media-treatment-assets-"));
+    const escapedAsset = join(project, "..", `${basename(project)}-escape.mp4`);
     mkdirSync(join(project, "capture"), { recursive: true });
     mkdirSync(join(project, "assets"), { recursive: true });
     writeFileSync(join(project, "capture", "talking-head.mp4"), "");
     writeFileSync(join(project, "assets", "photo.webp"), "");
     writeFileSync(join(project, "assets", "My Clip.mp4"), "");
+    writeFileSync(escapedAsset, "");
 
     try {
       expect(
@@ -248,8 +250,16 @@ describe("applyMediaTreatmentToHtml", () => {
       expect(() =>
         resolveMediaTreatmentSource(project, "compositions/scene.html", "missing.mp4"),
       ).toThrow(/Media file not found/);
+      expect(() =>
+        resolveMediaTreatmentSource(
+          project,
+          "compositions/scene.html",
+          `../../${basename(escapedAsset)}`,
+        ),
+      ).toThrow(/Media file not found/);
     } finally {
       rmSync(project, { recursive: true, force: true });
+      rmSync(escapedAsset, { force: true });
     }
   });
 
diff --git a/packages/core/src/mediaGradeAnalyzer.vendoredParity.test.ts b/packages/core/src/mediaGradeAnalyzer.vendoredParity.test.ts
index b5d186129..7f0c55f69 100644
--- a/packages/core/src/mediaGradeAnalyzer.vendoredParity.test.ts
+++ b/packages/core/src/mediaGradeAnalyzer.vendoredParity.test.ts
@@ -28,6 +28,26 @@ lavfi.signalstats.UAVG=125
 lavfi.signalstats.VAVG=135
 lavfi.signalstats.SATAVG=60`;
 
+const UNDEREXPOSED_SIGNALSTATS = `frame:0 pts:0 pts_time:0
+lavfi.signalstats.YMIN=2
+lavfi.signalstats.YLOW=8
+lavfi.signalstats.YAVG=50
+lavfi.signalstats.YHIGH=120
+lavfi.signalstats.YMAX=135
+lavfi.signalstats.UAVG=128
+lavfi.signalstats.VAVG=128
+lavfi.signalstats.SATAVG=30`;
+
+const BLOWN_HIGHLIGHT_SIGNALSTATS = `frame:0 pts:0 pts_time:0
+lavfi.signalstats.YMIN=70
+lavfi.signalstats.YLOW=90
+lavfi.signalstats.YAVG=200
+lavfi.signalstats.YHIGH=248
+lavfi.signalstats.YMAX=255
+lavfi.signalstats.UAVG=128
+lavfi.signalstats.VAVG=128
+lavfi.signalstats.SATAVG=30`;
+
 const PROBE: GradeMediaProbe = {
   duration: 4,
   colorSpace: "bt2020nc",
@@ -36,8 +56,8 @@ const PROBE: GradeMediaProbe = {
   pixelFormat: "yuv420p10le",
 };
 
-function productResult() {
-  const frames = parseMediaTreatmentSignalStats(SIGNALSTATS);
+function productResult(signalStats = SIGNALSTATS) {
+  const frames = parseMediaTreatmentSignalStats(signalStats);
   const summary = summarizeMediaTreatmentAnalysis(PROBE, frames);
   return {
     frames,
@@ -47,13 +67,13 @@ function productResult() {
   };
 }
 
-async function vendoredResult() {
+async function vendoredResult(signalStats = SIGNALSTATS) {
   const moduleUrl = new URL(
     "../../../skills/media-use/scripts/lib/grade-analyzer.mjs",
     import.meta.url,
   );
   const analyzer = await import(moduleUrl.href);
-  const frames = analyzer.parseMediaTreatmentSignalStats(SIGNALSTATS);
+  const frames = analyzer.parseMediaTreatmentSignalStats(signalStats);
   const summary = analyzer.summarizeMediaTreatmentAnalysis(PROBE, frames);
   return {
     frames,
@@ -67,4 +87,14 @@ describe("vendored media grade analyzer parity", () => {
   it("keeps the standalone skill copy aligned with the typed product module", async () => {
     expect(await vendoredResult()).toEqual(productResult());
   });
+
+  it.each([
+    ["underexposed", UNDEREXPOSED_SIGNALSTATS, 1],
+    ["blown-highlight", BLOWN_HIGHLIGHT_SIGNALSTATS, -1],
+  ])("covers the %s exposure branch", async (_, signalStats, expectedSign) => {
+    const product = productResult(signalStats);
+
+    expect(Math.sign(product.adjust.adjust.exposure)).toBe(expectedSign);
+    expect(await vendoredResult(signalStats)).toEqual(product);
+  });
 });