Folds in the sharpest refinement: business logic and art-dag are the SAME op-DAG structure,
differing only in the CAPABILITIES their nodes require — so the runner is DERIVED, not chosen.
A node declares :needs (wait→suspend, fan-out→parallel, heavy→offload); a runner advertises
:capabilities (op-table {effect,branch,each}; Erlang +suspend; celery-sx +parallel,retry,offload);
artdag/analyze computes a DAG's required set → its minimum runner; the binder checks required ⊆
runner-caps (fail fast). The sync/durable/distributed split falls out of the DAG (a {effect}-only
DAG runs with zero ceremony; a wait node auto-requires Erlang) — turning 'simple in SX / complex
in Erlang' from a judgment call into a derivable property. Removed the :runner hint from the type
binding; P0.2 gains the hypothesis test (natural-as-a-DAG? + flip-to-wait fails fast); runner
contract gains :capabilities; type-def editor can show the derived classification.
Doc-only.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
giles
8c48cac46f