Architecture
Status: Partially migrated. The lease-broker security-contract pages below are current references; the remaining architecture pages are still being classified.
This chapter is the canonical home for Mosaic Stack's system model, component boundaries, data and control flow, security model, architecture decisions, and RFCs. It explains why the system has its shape; it does not replace PRD.md, TASKS.md, or the API contract.
Promoted pages
lease-broker-protocol.md— authenticated Unix-socket protocol, identity binding, framing, persistence, and lease transitions.lease-broker-security.md— identity, ancestry, filesystem, whole-class, observer, and named residual security boundaries.mutator-class-gate.md— default-deny tool authorization, runtime adapters, launch choke point, and parser assurance boundary.compaction-revocation.md— Claude/Pi observer lifecycle, runtime generations, revocation, and the bounded residual stale window.channel-protocol.md— current shared channel DTOs and Discord compatibility baseline, with unimplemented adapter work explicitly marked draft.decisions/mos-runtime-portability-m1.md— current logical identity, connector lease, grant, audit, and fencing decision; connector activation remains held.
These pages are current security-contract references and are consumed by the lease-broker acceptance suites. Their live deployment gaps remain explicitly labeled in the pages; this migration does not change runtime behavior.
Planned pages
| Path | Purpose | Status |
|---|---|---|
system-overview.md |
Platform boundary and major request, event, and agent-runtime flows. | Planned. |
component-map.md |
Apps, packages, plugins, and dependency ownership. | Planned. |
data-flow.md |
Data, event, and control-plane movement. | Planned. |
security-model.md |
Trust boundaries, authority, authentication, and authorization model. | Planned. |
decisions/ |
Approved architecture decision records. | Partially migrated. |
rfcs/ |
Proposals and protocol RFCs. | Draft egress RFC indexed. |
Draft RFCs
rfcs/optional-ai-egress-gateways.md— proposed model-egress boundary; not approved or integrated.
Promoted pages must be linked here, from DEVELOPER-GUIDE/README.md, and from SITEMAP.md. Do not create duplicate architecture pages in docs/mosaic-stack/ or the docs root.
Migration backlog — not current architecture
docs/README.md— current documentation contract and placement rules.Documentation information architecture design— approved documentation structure decision, not product architecture.Documentation catalog audit— evidence and migration recommendations, not normative architecture.
Source-of-truth boundary
Architecture pages explain approved design and current system boundaries. Requirements remain in PRD.md; active work remains in TASKS.md; executable behavior remains authoritative in source and tests. Draft proposals belong in rfcs/ or docs/plans/, with status clearly labeled.