Search-engine boundaries
Local markup checks cannot know what a crawler fetched, rendered, indexed or selected as canonical. Search engines may rewrite title links/snippets, choose different canonicals, ignore invalid or ineligible structured data, and apply live HTTP/robots conditions that are not present in pasted text. Treat these tools as pre-publish QA, then verify live behavior with the relevant search-engine tools.
Publication preflight, not an SEO score
Generated or pasted SEO data is checked for concrete structural conflicts, malformed values and handoff risks. The tool does not predict rankings, indexing certainty or rich-result eligibility.