Design community rule packs without weakening safety

[Muawiya-contact]

Goal

Design a community rule-pack architecture.

Diskern should eventually make it easy for contributors to add rules for tools they know, without every rule needing to ship directly in the core database.

Why this is super advanced

Rules affect user trust and safety. Community rules need validation, provenance, protected-rule precedence, versioning, and a clear review path.

Existing safety invariant

External rules already cannot shadow embedded protected rules:

pub fn with_embedded_protected_rules(self) -> Self {
    let mut rules = RulesDb::embedded()
        .rules
        .into_iter()
        .filter(|rule| rule.verdict == Verdict::Protected)
        .collect::<Vec<_>>();
    rules.extend(self.rules);
    Self::new(self.version, rules)
}

That invariant must stay true.

Suggested deliverable

Start with a design document before code:

• rule pack format
• pack metadata and versioning
• how packs are enabled/disabled
• how protected rules always win
• how CI validates packs

Acceptance criteria

• No code is required for the first PR if the design is strong.
• The design keeps protected rules authoritative.
• The design explains review and trust boundaries in simple language.