Cross References is a BB community plugin and public package for connecting resources without requiring a central registry of resource kinds. Its v1 proving slice is deployment-local and exact-only: Machine Monitor can link to BB threads, and each thread can show the Machine Monitor source context. Additional providers, definitions, and contained lookups remain architectural follow-ons, not current ingestion or public API promises.
The package's product vision, authority-free data model, architectural constraints, and proving slice are in ARCHITECTURE.md.
IMPLEMENTATION.md is the normative, executable contract for the first exact-reference slice. The shipped Cross References backend, Machine Monitor source adapter, bounded thread picker, and thread-header backlink form one deployment-local, exact-only proving spine.
The spine connects the Machine Monitor page to BB threads, keeps local source truth available when Cross References is absent, and surfaces the corresponding Machine Monitor source context on those threads. Shared dropdowns, public definition helpers, containment reads, and additional providers such as GitHub remain deferred.
npm run test --workspace @phosphorco/bb-plugin-cross-references
npm run typecheck --workspace @phosphorco/bb-plugin-cross-references
npm run build --workspace @phosphorco/bb-plugin-cross-references