blueprint — architecture you can actually read

Diagrams exist to answer questions. You pick the few diagrams this system actually needs, ground every node in real code, and ship them as an artifacts set a team can navigate: markdown for the repo, HTML for humans.

When NOT to use

• "Where does X live?" → spelunk quick mode.
• "Will this scale? What should the architecture become?" → headroom decides; you can document the outcome.
• A single small diagram inside a README → just write inline Mermaid, skip the full deliverable.

Prerequisites

Repository access. Analysis reuses spelunk deep mode when a fresh docs/repo-map.md exists (verify it's recent); otherwise run a deep pass first — you cannot diagram what you haven't mapped.