Architecture

Yupana is a peer of Bobbin and Quipu, not a feature of either. It quarantines the heavy language toolchains (tree-sitter grammars, LSP servers, any CPG/dataflow machinery), holds a hot structural graph, and feeds three consumers: Bobbin (fusion), Quipu (promotion on commit), and the Gas Town broker/Aegis (per-tenant blast radius as a trust boundary).

   MCP (rmcp: stdio + HTTP/axum)  ·  CLI (clap)
   (a parallel REST HTTP API is Phase 3 — FR-27)
                    │
              Query / Serve layer
   refs · defs · callgraph · dataflow · blast-radius · verify
   (resolve against base + tenant overlay, tier/freshness tagged)
                    │
              Tenancy layer
   shared read-only base  +  per-tenant copy-on-write overlays
                    │
              Extraction layer
   tree-sitter (breadth) · LSP (precision) · CPG/dataflow (Phase 2)
                    │
   file-watch (notify) · git baseline · overlay cache
                    │
   Promotion boundary → Quipu (SHACL-validated Turtle)

The routing rule

Bobbin is on the request path only when fusion or ranking adds value. Multi-signal retrieval goes through Bobbin. Single-signal, analysis-only queries — edit verification, blast radius, live structure lookups — go straight to Yupana, and policy consumers like the broker read Yupana directly.

See the Specification §7 for the full component diagram and the proposed source layout.