diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index cd7387e966..857d951d75 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -368,6 +368,10 @@ jobs:
           shopt -s nullglob
           found_windows_manifest=false
           for x64_manifest in release-assets/*-win-x64.yml; do
+            if [[ "$(basename "$x64_manifest")" == builder-debug-* ]]; then
+              continue
+            fi
+
             arm64_manifest="${x64_manifest/-x64.yml/-arm64.yml}"
             output_manifest="${x64_manifest/-win-x64.yml/.yml}"
             if [[ ! -f "$arm64_manifest" ]]; then
diff --git a/scripts/release-smoke.ts b/scripts/release-smoke.ts
index 9c4a415106..0d95b4945d 100644
--- a/scripts/release-smoke.ts
+++ b/scripts/release-smoke.ts
@@ -1,5 +1,13 @@
 import { execFileSync } from "node:child_process";
-import { cpSync, mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
+import {
+  cpSync,
+  existsSync,
+  mkdirSync,
+  mkdtempSync,
+  readFileSync,
+  rmSync,
+  writeFileSync,
+} from "node:fs";
 import { tmpdir } from "node:os";
 import { dirname, join, resolve } from "node:path";
 import { fileURLToPath } from "node:url";
@@ -70,12 +78,15 @@ releaseDate: '2026-03-08T10:36:07.540Z'
   return { arm64Path, x64Path };
 }
 
-function writeWindowsManifestFixtures(targetRoot: string): { arm64Path: string; x64Path: string } {
+function writeWindowsManifestFixtures(
+  targetRoot: string,
+  channel: string,
+): { arm64Path: string; x64Path: string } {
   const assetDirectory = resolve(targetRoot, "release-assets");
   mkdirSync(assetDirectory, { recursive: true });
 
-  const arm64Path = resolve(assetDirectory, "latest-win-arm64.yml");
-  const x64Path = resolve(assetDirectory, "latest-win-x64.yml");
+  const arm64Path = resolve(assetDirectory, `${channel}-win-arm64.yml`);
+  const x64Path = resolve(assetDirectory, `${channel}-win-x64.yml`);
 
   writeFileSync(
     arm64Path,
@@ -112,12 +123,46 @@ releaseDate: '2026-03-08T10:36:07.540Z'
   return { arm64Path, x64Path };
 }
 
+function writeWindowsBuilderDebugFixtures(targetRoot: string): {
+  arm64Path: string;
+  x64Path: string;
+} {
+  const assetDirectory = resolve(targetRoot, "release-assets");
+  mkdirSync(assetDirectory, { recursive: true });
+
+  const arm64Path = resolve(assetDirectory, "builder-debug-win-arm64.yml");
+  const x64Path = resolve(assetDirectory, "builder-debug-win-x64.yml");
+  const debugFixture = `arm64:
+  firstOrDefaultFilePatterns:
+    - '**/*'
+nsis:
+  script: |-
+    !include "example.nsh"
+`;
+
+  writeFileSync(arm64Path, debugFixture);
+  writeFileSync(x64Path, debugFixture);
+
+  return { arm64Path, x64Path };
+}
 function assertContains(haystack: string, needle: string, message: string): void {
   if (!haystack.includes(needle)) {
     throw new Error(message);
   }
 }
 
+function assertExists(path: string, message: string): void {
+  if (!existsSync(path)) {
+    throw new Error(message);
+  }
+}
+
+function assertMissing(path: string, message: string): void {
+  if (existsSync(path)) {
+    throw new Error(message);
+  }
+}
+
 const tempRoot = mkdtempSync(join(tmpdir(), "t3-release-smoke-"));
 
 try {
@@ -211,15 +256,52 @@ try {
     "Merged manifest is missing the x64 asset.",
   );
 
-  const { arm64Path: winArm64Path, x64Path: winX64Path } = writeWindowsManifestFixtures(tempRoot);
+  const { arm64Path: winArm64Path, x64Path: winX64Path } = writeWindowsManifestFixtures(
+    tempRoot,
+    "latest",
+  );
+  const mergedWindowsManifestPath = resolve(tempRoot, "release-assets/latest.yml");
+  const { arm64Path: nightlyWinArm64Path, x64Path: nightlyWinX64Path } =
+    writeWindowsManifestFixtures(tempRoot, "nightly");
+  const mergedNightlyWindowsManifestPath = resolve(tempRoot, "release-assets/nightly.yml");
+  const { arm64Path: previewWinArm64Path, x64Path: previewWinX64Path } =
+    writeWindowsManifestFixtures(tempRoot, "preview");
+  const mergedPreviewWindowsManifestPath = resolve(tempRoot, "release-assets/preview.yml");
+  const { arm64Path: winDebugArm64Path, x64Path: winDebugX64Path } =
+    writeWindowsBuilderDebugFixtures(tempRoot);
   execFileSync(
-    process.execPath,
+    "bash",
     [
-      resolve(repoRoot, "scripts/merge-update-manifests.ts"),
-      "--platform",
-      "win",
-      winArm64Path,
-      winX64Path,
+      "-lc",
+      `
+        release_assets_dir=${JSON.stringify(resolve(tempRoot, "release-assets"))}
+        shopt -s nullglob
+        found_windows_manifest=false
+        for x64_manifest in "$release_assets_dir"/*-win-x64.yml; do
+          if [[ "$(basename "$x64_manifest")" == builder-debug-* ]]; then
+            continue
+          fi
+
+          arm64_manifest="\${x64_manifest/-x64.yml/-arm64.yml}"
+          output_manifest="\${x64_manifest/-win-x64.yml/.yml}"
+          if [[ ! -f "$arm64_manifest" ]]; then
+            echo "Missing matching arm64 Windows manifest for $x64_manifest" >&2
+            exit 1
+          fi
+
+          found_windows_manifest=true
+          node ${JSON.stringify(resolve(repoRoot, "scripts/merge-update-manifests.ts"))} --platform win \
+            "$arm64_manifest" \
+            "$x64_manifest" \
+            "$output_manifest"
+          rm -f "$arm64_manifest" "$x64_manifest"
+        done
+
+        if [[ "$found_windows_manifest" != true ]]; then
+          echo "No Windows updater manifests found to merge." >&2
+          exit 1
+        fi
+      `,
     ],
     {
       cwd: repoRoot,
@@ -227,7 +309,7 @@ try {
     },
   );
 
-  const mergedWindowsManifest = readFileSync(winArm64Path, "utf8");
+  const mergedWindowsManifest = readFileSync(mergedWindowsManifestPath, "utf8");
   assertContains(
     mergedWindowsManifest,
     "T3-Code-9.9.9-smoke.0-arm64.exe",
@@ -238,6 +320,57 @@ try {
     "T3-Code-9.9.9-smoke.0-x64.exe",
     "Merged Windows manifest is missing the x64 asset.",
   );
+  const mergedNightlyWindowsManifest = readFileSync(mergedNightlyWindowsManifestPath, "utf8");
+  assertContains(
+    mergedNightlyWindowsManifest,
+    "T3-Code-9.9.9-smoke.0-arm64.exe",
+    "Merged nightly Windows manifest is missing the arm64 asset.",
+  );
+  assertContains(
+    mergedNightlyWindowsManifest,
+    "T3-Code-9.9.9-smoke.0-x64.exe",
+    "Merged nightly Windows manifest is missing the x64 asset.",
+  );
+  const mergedPreviewWindowsManifest = readFileSync(mergedPreviewWindowsManifestPath, "utf8");
+  assertContains(
+    mergedPreviewWindowsManifest,
+    "T3-Code-9.9.9-smoke.0-arm64.exe",
+    "Merged preview Windows manifest is missing the arm64 asset.",
+  );
+  assertContains(
+    mergedPreviewWindowsManifest,
+    "T3-Code-9.9.9-smoke.0-x64.exe",
+    "Merged preview Windows manifest is missing the x64 asset.",
+  );
+  assertMissing(
+    winArm64Path,
+    "Windows release smoke unexpectedly kept the arm64 updater manifest.",
+  );
+  assertMissing(winX64Path, "Windows release smoke unexpectedly kept the x64 updater manifest.");
+  assertMissing(
+    nightlyWinArm64Path,
+    "Windows release smoke unexpectedly kept the nightly arm64 updater manifest.",
+  );
+  assertMissing(
+    nightlyWinX64Path,
+    "Windows release smoke unexpectedly kept the nightly x64 updater manifest.",
+  );
+  assertMissing(
+    previewWinArm64Path,
+    "Windows release smoke unexpectedly kept the preview arm64 updater manifest.",
+  );
+  assertMissing(
+    previewWinX64Path,
+    "Windows release smoke unexpectedly kept the preview x64 updater manifest.",
+  );
+  assertExists(
+    winDebugArm64Path,
+    "Windows release smoke unexpectedly removed the arm64 builder debug fixture.",
+  );
+  assertExists(
+    winDebugX64Path,
+    "Windows release smoke unexpectedly removed the x64 builder debug fixture.",
+  );
 
   console.log("Release smoke checks passed.");
 } finally {