Signal 08 of 09 · Nebula Diagnostic Spec v1.0.0

SEO Foundations

Can search systems retrieve and interpret the page foundations?

Decision rule

Core retrieval elements must be present, unique, and consistent: crawlable status, canonical URL, title, meta description, heading hierarchy, and indexability directives. A run flags missing, duplicated, or contradictory foundations.

What the engine inspects

  • ·HTTP status and robots directives
  • ·canonical tag
  • ·title and meta description
  • ·heading structure

How to check it yourself

  1. View page source: check title, meta description, canonical tag, and heading hierarchy.
  2. Confirm the page is indexable and the canonical is self-referencing where intended.
  3. Missing elements, duplicates across pages, or contradictions (for example a canonical pointing elsewhere while internal links target this page) fail the signal.

The engine automates this inspection and attaches measured evidence to every failing condition. A manual pass is not a substitute for the recorded evidence trail, but it should agree with it.

Pass / fail examples

Pass

Self-referencing canonical, unique title and description, single H1, indexable. Clear.

Fail

Canonical points to a different URL while an internal link targets this one as the destination. Contradiction flagged.