Phase 32 foundation. The SaaS control plane (private molecule-controlplane
repo) provisions one platform instance per customer org on Fly Machines
and sets MOLECULE_ORG_ID=<uuid> on the machine. Its subdomain router
forwards requests with X-Molecule-Org-Id=<uuid>.
TenantGuard:
- When MOLECULE_ORG_ID is set → every non-allowlisted request must carry a
matching X-Molecule-Org-Id header. Mismatched/missing header → 404 (not
403 — don't leak tenant existence by letting probers distinguish "wrong
org" from "route doesn't exist").
- When unset → passthrough. Self-hosted / dev / CI behavior unchanged.
- Allowlist is exact-match, not prefix — /health and /metrics only.
No orgs table, no signup, no billing, no Fly provisioning in this repo —
all that lives in the private control plane. The public repo's SaaS
surface is exactly this one middleware.
6 tests covering: unset-is-passthrough, matching header, mismatched
header 404 (with empty body), missing header 404, allowlist bypass, and
allowlist-is-exact-match.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2094f4f0c2