Initial import of overview from zapier monorepo

06-address-routing.md

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+# 6. Address routing (including unplanned functions)
+
+NATS **addresses** (subjects) are the extension point. A new search, store, or job type is a new address plus a process that listens — not a new Zapier TCP client.
+
+## Pattern
+
+```text
+verae.access.<plane>.<area>.<resource>.<action>   # ingress (one plane)
+verae.access.authz.check                          # authorization step
+verae.<area>.<resource>.<action>                  # internal bus
+verae.<area>.<resource>.reply.<correlationId>
+```
+
+Planes: `zapier` | `web` | `api` | `leaf` | `staff`. Default deny. A leaf cannot `balance.adjust`; Zapier cannot `statement.get`; a browser cannot `archive.put`.
+
+| Piece | Example | Meaning |
+|-------|---------|---------|
+| `verae` | — | Verae bus (not Zapier) |
+| `area` | `zapier`, `archive`, `search`, `store` | Product slice |
+| `resource` | `jobs`, `hashes`, `blobs` | Noun |
+| `action` | `watch`, `query`, `put`, `in` | Verb |
+| `reply.<id>` | — | Correlated response |
+
+**Queue group** (work sharing): `area-resource-action` (e.g. `job-poller`).  
+**No queue group** (fan-out): archive/tree **query** so every node sees every lookup.
+
+## Adding something that does not exist yet
+
+1. Copy the independent repo **[verae-nats-process](https://git.georgelambert.org/marchon/verae-nats-process)** (`packages/verae-nats-process`).
+2. Rename `verae.example.process.in` / `.out` / `.reply.*` in `src/subjects.js`.
+3. Add a row to that repo’s `ROUTING.md` and to [INDEX.md](INDEX.md).
+4. Register the process in `verae-fleet` (`min`/`max`, machines, roles).
+5. If an access plane must call it, add the subject to **verae-access-authz** policy for that plane only. Zapier still never sees NATS.
+
+Do **not** invent a public NATS URL for Zapier. Do **not** reuse `verae.archive.query` as a queue group.
+
+![Address expansion](diagrams/routing.svg)