The map

The map is the derived half of the coherence layer: contexts and their public API, Ecto schemas with real types and associations, Phoenix routes with LiveView unwrapped, Oban workers with queue and cron wiring. It regenerates on demand, which is the whole trick: a document produced by reflection cannot drift from the code it reflects.

Derivation is functional, not textual

Classification reads the compiled application, never source text: __schema__/1 makes a schema, __adapter__/0 makes a repo, __routes__/0 makes a router, the Oban.Worker behaviour makes a worker. Names lie; a module named Deals could be anything. Compiled modules don't.

That discipline was earned against a real ~185-module Phoenix app: an encrypted Cloak type living in the schema layer (caught as an Ecto type, not a schema), contexts with zero CRUD-named functions, belongs_to associations with custom foreign keys. The map reports what the code is, not what its names suggest.

What it looks like

### MyApp.Deals — domain [surface:df8be63a83b8]

**API** (32): approve_deal/1 create_deal/1 extract_deal_data/1 ...
**Schemas:** Deal, DealParty, DealPartyFeeComponent

### MyApp.Deals.Deal → deals
- fields: ..., side:enum(listing|buyer|both|lease|referral),
  status:enum(draft|needs_review|approved|posting|posted|reversed), ...
- belongs_to reviewed_by → MyApp.Users.User via reviewed_by_user_id

Entries read like the language of the business because they are the business, reflected out of the compiled code. Enum vocabularies, custom foreign keys, queue wiring: the facts agents otherwise rediscover by grepping, in one git-tracked file whose PR diff is the ontology change.

The rules it lives by

100% derived. No hand-authored content survives regeneration, by design. Anything a human needs to say belongs in an intent card, not the map.
Deterministic. Stable ordering, no timestamps. Regenerating without a code change is a no-op diff, so staleness is simple byte inequality and the CI gate can prove freshness.
Compiled modules and app config only. Never source text, never a running server, never the database. The map derives anywhere mix compile runs, including CI.

Surface hashes

Every context heading carries a hash of its public function surface; that is the [surface:df8be63a83b8] above. Those hashes are what intent cards bind to: when a context's surface moves, every card bound to the old surface is flagged until a human re-reviews it. The map states what is. The hash turns that statement into something other documents can be held to.