URL: /rules/core --- title: "Core SEO" description: "Essential meta tags and page structure for search engines" --- Essential meta tags and page structure for search engines ## Rules Detects mismatch between HTML canonical tag and Link header Validates canonical URL presence and format Checks for proper character encoding declaration Checks for valid HTML5 doctype declaration Checks for favicon presence Validates H1 tag presence and uniqueness Validates meta description presence and length Validates page title presence and length Detects pages preventing search engine snippets Validates Open Graph meta tags for social sharing Checks robots meta tag for indexing directives Checks that page titles are unique across the site Validates Twitter Card meta tags ## Disable All Core SEO Rules ```toml squirrel.toml [rules] disable = ["core/*"] ```