diff --git a/scripts/docs-semantic-core.mjs b/scripts/docs-semantic-core.mjs
index 199d685..d90127b 100644
--- a/scripts/docs-semantic-core.mjs
+++ b/scripts/docs-semantic-core.mjs
@@ -1212,13 +1212,27 @@ function describeValue(value) {
 }
 
 function normalizeHeadingText(value) {
-  return value
+  return stripHeadingTags(value)
     .replace(/\[([^\]]+)\]\([^)]+\)/g, '$1')
-    .replace(/<[^>]*>/g, '')
     .replace(/[`*_~]/g, '')
     .trim();
 }
 
+function stripHeadingTags(value) {
+  let result = '';
+  let insideTag = false;
+  for (const character of value) {
+    if (character === '<') {
+      insideTag = true;
+    } else if (character === '>') {
+      insideTag = false;
+    } else if (!insideTag) {
+      result += character;
+    }
+  }
+  return result;
+}
+
 function slugifyHeading(value) {
   return value
     .toLowerCase()
diff --git a/scripts/release-artifact-core.mjs b/scripts/release-artifact-core.mjs
index e100ec3..b4619ec 100644
--- a/scripts/release-artifact-core.mjs
+++ b/scripts/release-artifact-core.mjs
@@ -199,7 +199,14 @@ export function normalizeNpmViewPublicationState(value) {
 }
 
 export function inspectNpmAttestations(value, { packageName, version }) {
-  const expectedSuffix = `${encodeURIComponent(packageName).replace('%40', '@')}@${version}`;
+  const packageNamePattern = /^(?:@[a-z0-9][a-z0-9._~-]*\/[a-z0-9][a-z0-9._~-]*|[a-z0-9][a-z0-9._~-]*)$/;
+  const validPackageName =
+    typeof packageName === 'string' &&
+    packageName.length <= 214 &&
+    packageNamePattern.test(packageName);
+  const validVersion = typeof version === 'string' && /^\d+\.\d+\.\d+$/.test(version);
+  const expectedIdentity =
+    validPackageName && validVersion ? `${packageName}@${version}` : null;
   const entries = Array.isArray(value) ? value : [value];
   const attestation = entries.length === 1 ? entries[0] : null;
   const url = attestation?.url;
@@ -208,11 +215,10 @@ export function inspectNpmAttestations(value, { packageName, version }) {
   if (entries.length !== 1) {
     errors.push(`npm view must return exactly one attestation, received ${entries.length}`);
   }
-  if (
-    typeof url !== 'string' ||
-    !url.startsWith('https://registry.npmjs.org/-/npm/v1/attestations/') ||
-    !decodeURIComponent(url).endsWith(expectedSuffix)
-  ) {
+  if (!validPackageName || !validVersion) {
+    errors.push('npm attestation identity must use an exact package name and semantic version');
+  }
+  if (!isExactNpmAttestationUrl(url, expectedIdentity)) {
     errors.push('npm attestation URL does not identify the exact package version');
   }
   if (predicateType !== 'https://slsa.dev/provenance/v1') {
@@ -226,6 +232,31 @@ export function inspectNpmAttestations(value, { packageName, version }) {
   };
 }
 
+function isExactNpmAttestationUrl(value, expectedIdentity) {
+  if (typeof value !== 'string' || expectedIdentity == null) {
+    return false;
+  }
+  try {
+    const parsed = new URL(value);
+    const pathPrefix = '/-/npm/v1/attestations/';
+    if (
+      parsed.protocol !== 'https:' ||
+      parsed.hostname !== 'registry.npmjs.org' ||
+      parsed.port !== '' ||
+      parsed.username !== '' ||
+      parsed.password !== '' ||
+      parsed.search !== '' ||
+      parsed.hash !== '' ||
+      !parsed.pathname.startsWith(pathPrefix)
+    ) {
+      return false;
+    }
+    return decodeURIComponent(parsed.pathname.slice(pathPrefix.length)) === expectedIdentity;
+  } catch {
+    return false;
+  }
+}
+
 function publicationFailure(
   version,
   artifactIntegrity,
diff --git a/test/docsSemantic.test.mjs b/test/docsSemantic.test.mjs
index ec1bc90..a763685 100644
--- a/test/docsSemantic.test.mjs
+++ b/test/docsSemantic.test.mjs
@@ -494,4 +494,18 @@ describe('documentation semantic gate', () => {
       { text: 'A.B', anchor: 'ab-1' },
     ]);
   });
+
+  it('removes nested heading tags without producing a new tag-shaped substring', () => {
+    const headings = parseHeadings(
+      '# <code>API</code>\n\n## <<script>alert</script>\n\n## Before <em>and</em> after\n\n## Unclosed <script\n\n## <scr<script>ipt>'
+    );
+    expect(headings).toEqual([
+      { text: 'API', anchor: 'api' },
+      { text: 'alert', anchor: 'alert' },
+      { text: 'Before and after', anchor: 'before-and-after' },
+      { text: 'Unclosed', anchor: 'unclosed' },
+      { text: 'ipt', anchor: 'ipt' },
+    ]);
+    expect(headings.every(({ text }) => !/[<>]/u.test(text))).toBe(true);
+  });
 });
diff --git a/test/releaseArtifact.test.mjs b/test/releaseArtifact.test.mjs
index 0f231fe..5566cfe 100644
--- a/test/releaseArtifact.test.mjs
+++ b/test/releaseArtifact.test.mjs
@@ -144,4 +144,49 @@ describe('release artifact contract', () => {
       error: expect.stringContaining('exactly one attestation'),
     });
   });
+
+  it('parses the exact npm attestation URL identity without substring sanitization', () => {
+    const provenance = { predicateType: 'https://slsa.dev/provenance/v1' };
+    expect(
+      inspectNpmAttestations(
+        {
+          url: 'https://registry.npmjs.org/-/npm/v1/attestations/%40scope%2Fpackage@1.2.3',
+          provenance,
+        },
+        { packageName: '@scope/package', version: '1.2.3' }
+      )
+    ).toMatchObject({ status: 'passed' });
+
+    for (const url of [
+      'https://registry.npmjs.org/-/npm/v1/attestations/evil-package@1.2.3',
+      'https://registry.npmjs.org/-/npm/v1/attestations/package@1.2.3?identity=package@1.2.3',
+      'https://registry.npmjs.org/-/npm/v1/attestations/package@1.2.3#package@1.2.3',
+      'https://registry.npmjs.org.evil.example/-/npm/v1/attestations/package@1.2.3',
+      'https://package@registry.npmjs.org/-/npm/v1/attestations/package@1.2.3',
+      'https://registry.npmjs.org/-/npm/v1/attestations/%E0%A4%A',
+    ]) {
+      expect(
+        inspectNpmAttestations(
+          { url, provenance },
+          { packageName: 'package', version: '1.2.3' }
+        )
+      ).toMatchObject({
+        status: 'failed',
+        error: expect.stringContaining('exact package version'),
+      });
+    }
+
+    expect(
+      inspectNpmAttestations(
+        {
+          url: 'https://registry.npmjs.org/-/npm/v1/attestations/%2540scope%252Fpackage@1.2.3',
+          provenance,
+        },
+        { packageName: '@scope/package', version: '1.2.3' }
+      )
+    ).toMatchObject({
+      status: 'failed',
+      error: expect.stringContaining('exact package version'),
+    });
+  });
 });