great_cto reads your repo's stack and picks one of 10 archetypes. Each archetype sets a default security tier — the floor, not the cap. Signals during implementation (new payment deps, auth changes, PII fields, IAM diffs) can upgrade the tier at runtime.
Domain packs add depth for specialised archetypes:
ai-pack · web3-pack · enterprise-pack · data-pack.
Full tier model and signal matrix in
security-tiers.md.