two-repo system with one source-of-truth core.

┌──────────────┬────────────────────────────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Repo         │ Role                       │ What belongs there                                                                                                  │
├──────────────┼────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ NerfEngine   │ Primary monorepo           │ backend, graph/recon engines, RF/IP correlation, scythe.proto, server APIs, shared docs, architecture, blog posts   │
├──────────────┼────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ SCYTHE_APP   │ Deployable client repo     │ Android app, app-only UI/AR work, release artifacts, app-specific CI                                                │
└──────────────┴────────────────────────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

A good operating model for this project:

 1. Keep NerfEngine authoritative for contracts and cognition logic. If scythe.proto, forecast semantics, or backend payloads change, that repo leads.
 2. Keep SCYTHE_APP consuming, not redefining, contracts. App PRs should reference the backend commit/tag they depend on.
 3. Protect main in both repos: PR required, no direct pushes, status checks required.
 4. Use short-lived branches like feat/intent-hypotheses, feat/ar-overlay, fix/grpc-tail.
 5. Tag releases by surface: backend tags in NerfEngine, app tags in SCYTHE_APP; when protocol changes, note the compatible tag pair.
 6. Use labels aggressively: backend, app, proto, docs, research, breaking-change, operator-ui, cognition, rf.
 7. Put planning in GitHub Issues/Projects, not scattered markdown. Keep markdown for durable docs, architecture, and posts.
 8. Add repo hygiene: CODEOWNERS, PR template, issue templates, branch protection, changelog/release notes, and CI for the focused tests/builds you already run.

For this codebase specifically, I’d also separate production, experimental, and research-imported work more clearly inside NerfEngine. A simple top-level convention like core/, integration/, research/, and docs/—even if done gradually—will
make the repo much easier to govern as it grows.

If you want the strongest GitHub setup, the next concrete step is: GitHub Project for roadmap + branch protection + PR template + CODEOWNERS across both repos.