Falsifiable rules
These are not design preferences. Each invariant names a generalized failure scenario and the rule that prevents it. They are a growing release set, not a second set of the five contract families.
The failure
Temporary fallback states emit noindex. Crawlers cache it. Legitimate URLs disappear after recovery.
The rule
Tiers decide what a page may render. Robots directives come only from explicit indexability policy.
The failure
A timed-out existence check becomes 404 or 410. Latency shrinks the index.
The rule
Model support as supported, unsupported, and unknown. Only canonical evidence produces permanent absence.
The failure
A resolver says ready while production returns a placeholder or the wrong robots policy.
The rule
Validate sitemap and link eligibility against rendered output, not registry membership alone.
The failure
Suppression copy says no public claim while an adjacent module emits from $199.
The rule
One resolver. Suppression is a property of the page, not of a module.
The failure
A policy covers N of M emission surfaces. The rest keep leaking the claim.
The rule
Treat any partial implementation as unshipped, regardless of how many surfaces it covers.
The failure
Body, headers, JSON-LD, agent APIs, and sitemaps each re-derive the same fact.
The rule
One resolver per public fact. Every surface derives from it. Never copy. Never re-invent.
Scenario, not proof claim
An invariant without an applicable probe is a belief. When required probe inputs are missing, the result is UNMEASURED—not PASS.