---
id: MAS-WP-0006
type: workplan
title: "MAS address composer"
domain: communication
repo: mail-address-semantics
status: finished
owner: claude
topic_slug: coulomb-social
created: "2026-10-18"
updated: "2026-10-19"
origin: residual
origin_ref: MAS-WP-0003
state_hub_workstream_id: "0934280a-f85a-55f1-a17c-61c5255b5e3b"
---

# MAS address composer

Decision-gate outcome of MAS-WP-0002 (founder, 2026-10-18). Pulled
forward because provider configuration forms do not preserve MAS syntax:
the IONOS forwarding form refuses `=` and forces lower case, and Google
Groups lower-cases members (MAS-WP-0003 T04). Depends on the SCP-6/SCP-7
outcome in MAS-WP-0005.

## Scope and interface

```task
id: MAS-WP-0006-T01
status: done
priority: medium
state_hub_task_id: "13071dfc-fbaa-503e-bd0d-ddd6c2377758"
```

Define what the composer does: from a statute and an intent (resource,
facet, interaction), emit the canonical address and, when the statute
declares one, the forwarder-safe form (lower case, `--` separator). Warn
about the 64-octet budget and facet/interaction exclusivity. Decide
whether it is a new CLI command (the CLI has no generate command yet), a web page,
or both. The library side exists: `mas_core.generator.for_destination` (MAS-WP-0005 T09).

## Implement and test

```task
id: MAS-WP-0006-T02
status: done
priority: medium
state_hub_task_id: "69cb22fe-9995-55c3-91de-63eab5c09282"
```

Build it on `mas_core.generator`, with fixtures for the forms seen in
MAS-WP-0003.

## Outcome

- Interface (T01): a CLI command only, `mas compose DOMAIN TARGET [--facet F]
  [--interaction MODE] [--for DESTINATION] [--statute FILE | --no-discover]`.
  There is no web page: it would need a second parser in JS, and nothing
  asks for one yet. TARGET is `TYPE=ID` or a registry name.
- Output: the canonical address with its octet count. If the statute
  declares stand-ins, also the forwarder-safe form (stand-ins, then lower
  case). `--for` adds the named destination profiles. The composer warns
  when fewer than 16 of the 64 octets are left, and when the statute would
  not handle the address. It refuses facet + interaction (exit 1). A form
  the namespace would misread is reported as "cannot express".
- Tests (T02): `tests/test_compose.py`, using the MAS-WP-0003 forms
  (IONOS `ticket--gs-85qj8wc09p+comments`, Google Groups lower case,
  `ticket---callback`, `ticket=RE=2026-4711` not expressible).