SCAN: the open notation SCAN (System and Component Architecture Notation) is an open, human-readable notation for describing software systems. Sphere is built on it. SCAN itself is free and open. SCAN is the Architecture-as-Code substrate: the blueprint language for the living system model. Sphere turns that blueprint into plans, builds, verification, and memory. Without a shared notation, agents and people rebuild context from prose and file dumps every session. ## What SCAN describes - Components: services, apps, data stores, agents, external systems. - Connections: what talks to what, and how. - Ports and interfaces: where components connect. - Technology: what each component is built with. - Boundaries: groupings such as domains, teams or deployment zones. - Layout and views: how the model is drawn on a board. A SCAN model is plain text (YAML), so it can live in a repository, be reviewed like code, and be read by both people and AI agents — the same ground truth for BA, Dev, Architect, QA, and coding agents. ## Why an open notation matters - No lock-in for your architecture — the model is yours, in an open format. - Toolable — anyone can read, render or generate SCAN. - Shared language for people and AI agents. - Structured context that is far more useful to agents than prose alone or a pile of source files. - Context that persists across changes instead of being rebuilt each time. ## SCAN vs Sphere | | SCAN (free, open) | Sphere Desktop (product) | |---|---|---| | Notation and specification | Yes | Yes | | Browser whiteboard at app.spherescan.io | Yes (diagram canvas) | — | | Chat-first architect / orchestrator | — | Yes | | Plans, runs, builds, verification | — | Yes | | Private workspace with a live, reconciled model | — | Yes | | Persistent memory of plans, runs and verification | — | Yes | | Collaboration, governance, connected systems | — | Yes | app.spherescan.io is the free SCAN whiteboard — useful for trying the notation, not a substitute for Sphere Desktop. For how Desktop works (Chat, Plans, Runs, Diagram), see sphere-desktop.md. Learn more at https://spherescan.io.