Schema.org markup passes basic validity checks

A JSON syntax error in any <script type="application/ld+json"> block silently discards the entire schema — Google logs a parse failure and ignores the block, removing that page from Rich Results eligibility. Beyond syntax, schema-org Article and schema-org WebSite define required properties that must be present for Google to trust and surface the markup: an Article missing datePublished will not appear in Top Stories carousels regardless of content quality. Invalid structured data is equivalent to no structured data from Google's perspective, making this a direct ranking signal failure.

Lint all JSON-LD before embedding. The fastest fix is running each block through JSON.parse() in a build-time script or using the Google Rich Results Test against your staging URL. For BlogPosting, the required fields are headline, author (with @type: "Person" and name), datePublished, and image. For WebSite, the minimum is name and url.

Add a validation step in src/lib/schema.ts that asserts required fields at build time:

// src/lib/schema.ts
export function buildArticleSchema(post: Post) {
  if (!post.title || !post.publishedAt || !post.authorName) {
    throw new Error(`Article schema: missing required fields for "${post.slug}"`);
  }
  return {
    '@context': 'https://schema.org',
    '@type': 'BlogPosting',
    headline: post.title,
    datePublished: post.publishedAt,
    author: { '@type': 'Person', name: post.authorName },
  };
}

This catches missing properties at build time rather than silently shipping invalid schema to production.

• ID: schema-validity

• Severity: high

• What to look for: Count all JSON-LD blocks and enumerate which pass JSON parsing and which have syntax errors or missing required properties. Examine all <script type="application/ld+json"> blocks found in the project. Parse each as JSON and check: (1) JSON is syntactically valid (parseable without errors), (2) each block has a @context field set to "https://schema.org" or "http://schema.org", (3) each block has a @type field, (4) required properties for the given @type are present. For common types: WebSite requires name; Article/BlogPosting requires headline, author, datePublished; BreadcrumbList requires itemListElement; Organization requires name.

• Pass criteria: All JSON-LD blocks are valid JSON, have @context and @type, and include the required properties for their type. At least 90% of JSON-LD blocks must be syntactically valid with required properties present.

• Fail criteria: Any JSON-LD block has a JSON syntax error, missing @context or @type, or is missing a required property for its declared type.

• Skip (N/A) when: No JSON-LD blocks found in the project (caught by jsonld-present check).

• Cross-reference: For structured data content matching, see markup-content-match.

• Detail on fail: Identify the specific file, the @type, and the validation failure. Example: "Article schema in app/blog/[slug]/page.tsx is missing required 'datePublished' field. Organization schema has JSON syntax error near character 247."

• Remediation: Invalid structured data does not produce rich results and may be ignored by search engines entirely. Fix syntax errors by linting your JSON-LD objects before embedding them. For BlogPosting, required fields are: headline, author (with @type: Person and name), datePublished, dateModified, and description. Consult schema.org for required properties of other types.

  // Validate with Google Rich Results Test — fix missing properties in app/page.tsx JSON-LD blocks
  { "@context": "https://schema.org", "@type": "Organization", "name": "Required", "url": "Required" }