Native Workflows execution

Stelow uses the host's built-in workflows plugin as its native execution backend for recipes that are safe to run through the durable Workflows substrate. Eligible recipes are submitted through bb workflows run, their runId persists in the execution ledger, and status, cancellation, receipts, and artifacts reconcile back into the card. It is not a universal replacement: the execution router chooses the narrowest safe mode per recipe.

Why some work stays sequential

scope-batch declares workspace writes, dependency partitioning, file claims, parent verification, and gap escalation — operations needing a shared workspace and a parent-owned merge. A generic fan-out cannot prove two workers won't edit the same files or that the parent stays consistent after a worker fails. So scope-batch → coordinator-sequential until the host proves otherwise.

Pilot boundary

Native fan-out is allowed for exactly one pilot class: independent-disjoint-scopes-with-satisfied-claims. Everything else — overlaps, unsatisfied or missing claims, workspace-writing batches in general — stays sequential. A batch fans out only when every gate passes: capability (file-claims + isolated-workspace), admission (every scope presents a satisfied claim), disjointness (pairwise-disjoint file sets), bounded concurrency (cap + per-scope timeout + batch-cancel), per-scope receipts (claims, files touched, manifest), and parent merge with post-merge verification. Any gate failure falls back to sequential with no partial fan-out; one flag (native_pilot_allowed=false) rolls everything back with no code change.

Host behavior

Stelow probes the built-in plugin at runtime and uses the native path when the recipe is eligible; otherwise it fails soft to the explicit sequential fallback. The About tab and first-visit setup identify the dependency and offer install/enable actions — the package never installs or enables another plugin silently. The next safe step is a host-level claims-and-isolation contract, promoting only the scope classes that satisfy it.