{"ok":true,"kind":"crawlcheck-rulebook","v":1,"generated_at":"2026-10-07T17:43:46.602Z","score_version":28,"schema":"https://crawlcheck.io/schemas/rulebook.json","counts":{"rules":77,"by_kind":{"scan":52,"answer_correlation":5,"capability_mismatch":6,"self_audit":12,"mcp_server":2},"by_family":{"site":8,"headers":4,"mostly_code":3,"machine_files":11,"robots":13,"delivery":8,"jsonld":3,"nap":2,"answers":5,"capabilities":6,"self_audit":12,"mcp":1,"watch":1},"revised":7,"scored":48},"scans_counted":3137,"severity_scale":[{"level":"info"},{"level":"low"},{"level":"medium"},{"level":"high"},{"level":"critical"}],"method":{"revisions":"A rule that changes what it reports gets a new revision; a record keeps the revision that decided it, and a replay uses that revision, never today's.","share":"Share of counted scans that carried the code at least once, the same numbers /data publishes. Self-scans and opted-out sites are never counted.","grade":"Each finding has a level from info to critical. Open findings at medium and above lower the letter grade; fix them first."},"rules":[{"code":"HSTS_MISSING","kind":"scan","family":{"id":"headers","label":"Headers"},"title":"HTTPS is served without a Strict-Transport-Security header","meaning":"Strict-Transport-Security tells a browser that has visited once to use HTTPS for every later request without trying HTTP first. Without it, a typed or linked http:// address makes one plaintext request before the redirect. It does not change what crawlers receive or how the site ranks; it is a small, reversible hardening step, and it is listed at the lowest severity for that reason.","severity":{"level":"info"},"scored":true,"measured_on":"every scan","revision":{"current":1,"revised_at":null},"fix":{"advice":"Send Strict-Transport-Security: max-age=15552000; includeSubDomains on HTTPS responses (Cloudflare: SSL/TLS, Edge Certificates, HSTS). Leave preload off unless you intend a change that takes months to undo.","effort":"config","endpoint":"https://crawlcheck.io/api/fix/hsts?domain={domain}"},"share_of_scans":{"pct":9.3,"scans":292,"of_scans":3137,"basis":"share of counted scans that carried it; the same numbers /data publishes"},"links":{"self":"https://crawlcheck.io/rules#HSTS_MISSING","api":"https://crawlcheck.io/api/rules?code=HSTS_MISSING","glossary":["https://crawlcheck.io/glossary/hsts"],"workflow":null,"lineage":"https://crawlcheck.io/docs/lineage-coverage","explain_template":"https://crawlcheck.io/api/explain?id={report_id}&code=HSTS_MISSING"}}],"filter":{"code":"HSTS_MISSING"}}