diff --git a/.github/scripts/verify-release-artifacts.sh b/.github/scripts/verify-release-artifacts.sh
index b35a74651..4aef28d4a 100644
--- a/.github/scripts/verify-release-artifacts.sh
+++ b/.github/scripts/verify-release-artifacts.sh
@@ -13,27 +13,29 @@ if [[ ! -d "$artifact_root" ]]; then
   exit 1
 fi
 
+# Require exactly one regular file matching a path-scoped release artifact pattern.
 require_exactly_one_path() {
-  local path_pattern="$1" label="$2" count=0 matched_path=""
-  while IFS= read -r -d '' matched_path; do count=$((count + 1)); done < <(find "$artifact_root" -type f -path "$path_pattern" -print0)
+  local path_pattern="$1" label="$2" count=0
+  while IFS= read -r -d '' _; do count=$((count + 1)); done < <(find "$artifact_root" -type f -path "$path_pattern" -print0)
   if [[ $count -ne 1 ]]; then
     printf 'Expected exactly one %s, found %s.\n' "$label" "$count" >&2
     exit 1
   fi
 }
 
+# Require exactly one named operational artifact inside its platform-scoped directory.
 require_exactly_one_file() {
-  local file_name="$1" count=0 matched_path=""
-  while IFS= read -r -d '' matched_path; do count=$((count + 1)); done < <(find "$artifact_root" -type f -name "$file_name" -print0)
+  local directory="$1" file_name="$2" count=0
+  while IFS= read -r -d '' _; do count=$((count + 1)); done < <(find "$artifact_root/$directory" -type f -name "$file_name" -print0)
   if [[ $count -ne 1 ]]; then
-    printf 'Expected exactly one release artifact named %s, found %s.\n' "$file_name" "$count" >&2
+    printf 'Expected exactly one release artifact named %s in %s, found %s.\n' "$file_name" "$directory" "$count" >&2
     exit 1
   fi
 }
 
 expected_dirs=(
   "release-disksage-ubuntu-22.04-${run_attempt}"
-  "release-disksage-windows-latest-${run_attempt}"
+  "release-disksage-windows-2022-${run_attempt}"
   "release-disksage-macos-latest-${run_attempt}"
 )
 
@@ -55,22 +57,24 @@ if [[ -n "$unexpected_entry" ]]; then
   exit 1
 fi
 
-require_exactly_one_path '*/bundle/deb/*.deb' 'Debian bundle'
-require_exactly_one_path '*/bundle/appimage/*.AppImage' 'AppImage bundle'
-require_exactly_one_path '*/bundle/msi/*.msi' 'Windows MSI bundle'
-require_exactly_one_path '*/bundle/nsis/*.exe' 'Windows NSIS bundle'
-require_exactly_one_path '*/bundle/dmg/*.dmg' 'macOS DMG bundle'
+require_exactly_one_path "$artifact_root/${expected_dirs[0]}/bundle/deb/*.deb" 'Debian bundle'
+require_exactly_one_path "$artifact_root/${expected_dirs[0]}/bundle/appimage/*.AppImage" 'AppImage bundle'
+require_exactly_one_path "$artifact_root/${expected_dirs[1]}/bundle/msi/*.msi" 'Windows MSI bundle'
+require_exactly_one_path "$artifact_root/${expected_dirs[1]}/bundle/nsis/*.exe" 'Windows NSIS bundle'
+require_exactly_one_path "$artifact_root/${expected_dirs[2]}/bundle/dmg/*.dmg" 'macOS DMG bundle'
 
-for required_name in \
-  disksage-cloud-plan-linux-x86_64 \
-  disksage-duplicate-audit-linux-x86_64 \
-  disksage-cloud-plan-windows-x86_64.exe \
-  disksage-duplicate-audit-windows-x86_64.exe \
-  disksage-cloud-plan-macos-arm64 \
-  disksage-duplicate-audit-macos-arm64; do
-  require_exactly_one_file "$required_name"
-  require_exactly_one_file "$required_name.sha256"
-done
+require_exactly_one_file "${expected_dirs[0]}" disksage-cloud-plan-linux-x86_64
+require_exactly_one_file "${expected_dirs[0]}" disksage-cloud-plan-linux-x86_64.sha256
+require_exactly_one_file "${expected_dirs[0]}" disksage-duplicate-audit-linux-x86_64
+require_exactly_one_file "${expected_dirs[0]}" disksage-duplicate-audit-linux-x86_64.sha256
+require_exactly_one_file "${expected_dirs[1]}" disksage-cloud-plan-windows-x86_64.exe
+require_exactly_one_file "${expected_dirs[1]}" disksage-cloud-plan-windows-x86_64.exe.sha256
+require_exactly_one_file "${expected_dirs[1]}" disksage-duplicate-audit-windows-x86_64.exe
+require_exactly_one_file "${expected_dirs[1]}" disksage-duplicate-audit-windows-x86_64.exe.sha256
+require_exactly_one_file "${expected_dirs[2]}" disksage-cloud-plan-macos-arm64
+require_exactly_one_file "${expected_dirs[2]}" disksage-cloud-plan-macos-arm64.sha256
+require_exactly_one_file "${expected_dirs[2]}" disksage-duplicate-audit-macos-arm64
+require_exactly_one_file "${expected_dirs[2]}" disksage-duplicate-audit-macos-arm64.sha256
 
 checksum_files=()
 checksum_file=""
@@ -113,8 +117,7 @@ for checksum_file in "${checksum_files[@]}"; do
 done
 
 regular_file_count=0
-matched_path=""
-while IFS= read -r -d '' matched_path; do regular_file_count=$((regular_file_count + 1)); done < <(find "$artifact_root" -type f -print0)
+while IFS= read -r -d '' _; do regular_file_count=$((regular_file_count + 1)); done < <(find "$artifact_root" -type f -print0)
 if [[ $regular_file_count -ne 17 ]]; then
   printf 'Unexpected release artifact entries: expected exactly 17 regular files, found %s.\n' "$regular_file_count" >&2
   exit 1
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 980672cd7..30a69e363 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -259,6 +259,10 @@ jobs:
           path: release-artifacts
           merge-multiple: false
 
+      - name: Verify downloaded release artifact contract
+        shell: bash
+        run: bash .github/scripts/verify-release-artifacts.sh release-artifacts "${{ github.run_attempt }}"
+
       - name: Generate and validate source-bound SBOM
         shell: bash
         run: |
diff --git a/src/lib/releaseArtifactVerifierDirectoryContract.test.ts b/src/lib/releaseArtifactVerifierDirectoryContract.test.ts
new file mode 100644
index 000000000..e15cd8a43
--- /dev/null
+++ b/src/lib/releaseArtifactVerifierDirectoryContract.test.ts
@@ -0,0 +1,131 @@
+import { createHash } from 'node:crypto';
+import { mkdirSync, mkdtempSync, renameSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join, resolve } from 'node:path';
+import { spawnSync } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+const repositoryRoot = resolve(dirname(fileURLToPath(import.meta.url)), '../..');
+const runAttempt = '1';
+const platformDirectories = {
+  linux: `release-disksage-ubuntu-22.04-${runAttempt}`,
+  windows: `release-disksage-windows-2022-${runAttempt}`,
+  macos: `release-disksage-macos-latest-${runAttempt}`,
+} as const;
+
+/** Writes one fixture file, creating only the parent directories required by that fixture. */
+function write(path: string, bytes: Buffer | string) {
+  mkdirSync(dirname(path), { recursive: true });
+  writeFileSync(path, bytes);
+}
+
+/** Adds one operational CLI fixture together with its adjacent SHA-256 receipt. */
+function addCli(artifactRoot: string, directory: string, name: string) {
+  const bytes = Buffer.from(`cli:${name}`);
+  const assetPath = join(artifactRoot, directory, name);
+  write(assetPath, bytes);
+  write(
+    `${assetPath}.sha256`,
+    `${createHash('sha256').update(bytes).digest('hex')}  ${name}\n`,
+  );
+}
+
+/** Materializes the exact 17-file Linux, Windows, and macOS release artifact contract. */
+function materializeExactArtifactSet(artifactRoot: string) {
+  write(join(artifactRoot, platformDirectories.linux, 'bundle/deb/disksage.deb'), 'deb');
+  write(join(artifactRoot, platformDirectories.linux, 'bundle/appimage/disksage.AppImage'), 'appimage');
+  write(join(artifactRoot, platformDirectories.windows, 'bundle/msi/disksage.msi'), 'msi');
+  write(join(artifactRoot, platformDirectories.windows, 'bundle/nsis/disksage-setup.exe'), 'nsis');
+  write(join(artifactRoot, platformDirectories.macos, 'bundle/dmg/disksage.dmg'), 'dmg');
+
+  addCli(artifactRoot, platformDirectories.linux, 'disksage-cloud-plan-linux-x86_64');
+  addCli(artifactRoot, platformDirectories.linux, 'disksage-duplicate-audit-linux-x86_64');
+  addCli(artifactRoot, platformDirectories.windows, 'disksage-cloud-plan-windows-x86_64.exe');
+  addCli(artifactRoot, platformDirectories.windows, 'disksage-duplicate-audit-windows-x86_64.exe');
+  addCli(artifactRoot, platformDirectories.macos, 'disksage-cloud-plan-macos-arm64');
+  addCli(artifactRoot, platformDirectories.macos, 'disksage-duplicate-audit-macos-arm64');
+}
+
+/** Runs the repository-owned verifier against one isolated downloaded-artifact fixture. */
+function verify(artifactRoot: string) {
+  return spawnSync(
+    'bash',
+    [
+      resolve(repositoryRoot, '.github/scripts/verify-release-artifacts.sh'),
+      artifactRoot,
+      runAttempt,
+    ],
+    { cwd: repositoryRoot, encoding: 'utf8' },
+  );
+}
+
+describe('release artifact verifier directory contract', () => {
+  it.runIf(process.platform !== 'win32')(
+    'accepts the exact platform namespaces uploaded by the release matrix',
+    () => {
+      const fixtureRoot = mkdtempSync(join(tmpdir(), 'disksage-release-artifact-verifier-'));
+      const artifactRoot = join(fixtureRoot, 'release-artifacts');
+      try {
+        materializeExactArtifactSet(artifactRoot);
+
+        const result = verify(artifactRoot);
+
+        expect(result.status, result.stderr).toBe(0);
+        expect(result.stderr).toBe('');
+      } finally {
+        rmSync(fixtureRoot, { recursive: true, force: true });
+      }
+    },
+  );
+
+  it.runIf(process.platform !== 'win32')(
+    'rejects a Windows bundle that escaped its Windows artifact directory',
+    () => {
+      const fixtureRoot = mkdtempSync(join(tmpdir(), 'disksage-release-artifact-verifier-'));
+      const artifactRoot = join(fixtureRoot, 'release-artifacts');
+      try {
+        materializeExactArtifactSet(artifactRoot);
+        const source = join(artifactRoot, platformDirectories.windows, 'bundle/msi/disksage.msi');
+        const misplaced = join(artifactRoot, platformDirectories.linux, 'bundle/msi/disksage.msi');
+        mkdirSync(dirname(misplaced), { recursive: true });
+        renameSync(source, misplaced);
+
+        const result = verify(artifactRoot);
+
+        expect(result.status).not.toBe(0);
+        expect(result.stdout).toBe('');
+        expect(result.stderr).toContain('Windows MSI bundle');
+      } finally {
+        rmSync(fixtureRoot, { recursive: true, force: true });
+      }
+    },
+  );
+
+  it.runIf(process.platform !== 'win32')(
+    'rejects a Windows operational CLI and checksum outside the Windows artifact directory',
+    () => {
+      const fixtureRoot = mkdtempSync(join(tmpdir(), 'disksage-release-artifact-verifier-'));
+      const artifactRoot = join(fixtureRoot, 'release-artifacts');
+      try {
+        materializeExactArtifactSet(artifactRoot);
+        const cliName = 'disksage-cloud-plan-windows-x86_64.exe';
+        const source = join(artifactRoot, platformDirectories.windows, cliName);
+        const sourceChecksum = `${source}.sha256`;
+        const misplaced = join(artifactRoot, platformDirectories.linux, cliName);
+        const misplacedChecksum = `${misplaced}.sha256`;
+        renameSync(source, misplaced);
+        renameSync(sourceChecksum, misplacedChecksum);
+
+        const result = verify(artifactRoot);
+
+        expect(result.status).not.toBe(0);
+        expect(result.stdout).toBe('');
+        expect(result.stderr).toContain(cliName);
+        expect(result.stderr).toContain(platformDirectories.windows);
+      } finally {
+        rmSync(fixtureRoot, { recursive: true, force: true });
+      }
+    },
+  );
+});
\ No newline at end of file
diff --git a/src/lib/releaseTagArtifactVerifierContract.test.ts b/src/lib/releaseTagArtifactVerifierContract.test.ts
new file mode 100644
index 000000000..c24e4368a
--- /dev/null
+++ b/src/lib/releaseTagArtifactVerifierContract.test.ts
@@ -0,0 +1,29 @@
+import { readFileSync } from 'node:fs';
+import { dirname, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+const repositoryRoot = resolve(dirname(fileURLToPath(import.meta.url)), '../..');
+
+/** Reads the source-controlled release workflow with normalized line endings for stable assertions. */
+function readReleaseWorkflow(): string {
+  return readFileSync(resolve(repositoryRoot, '.github/workflows/release.yml'), 'utf8').replace(/\r\n?/g, '\n');
+}
+
+describe('tag release artifact verifier contract', () => {
+  it('runs the shared exact build-artifact verifier before generating the SBOM', () => {
+    const workflow = readReleaseWorkflow();
+    const attestStart = workflow.indexOf('\n  attest-release:\n');
+    const publishStart = workflow.indexOf('\n  publish-release:\n', attestStart);
+    expect(attestStart).toBeGreaterThanOrEqual(0);
+    expect(publishStart).toBeGreaterThan(attestStart);
+
+    const attestJob = workflow.slice(attestStart, publishStart);
+    const sharedVerifier = 'bash .github/scripts/verify-release-artifacts.sh release-artifacts "${{ github.run_attempt }}"';
+    const verifierOffset = attestJob.indexOf(sharedVerifier);
+    const sbomOffset = attestJob.indexOf('- name: Generate and validate source-bound SBOM');
+
+    expect(verifierOffset).toBeGreaterThanOrEqual(0);
+    expect(sbomOffset).toBeGreaterThan(verifierOffset);
+  });
+});
\ No newline at end of file