0.61.0-alpha · core 2026-09-18

BB child-thread substrate (skills/stelow-workflow-orchestrator/references/cli-tools/subagents.md). On BB-backed hosts a fresh BB child thread is an equivalent execution substrate for an independent subagent task under the identical contract (fresh context, no sibling communication, one independently owned output file, parent synthesizes). Parallel code execution, shared live state, lifecycle commands, and structured questions remain forbidden.
Host-plugin blueprint surfacing rules (docs/host-plugin-blueprint.md): child threads listed under their worker, automation proposes-never-disposes, fire-and-forget RPC writes await the server response, automation-rules and thread-children indexed as portable lib modules.

Downstream freshness is the consumer's job: poll the releases API (or the pinned main commit) on your own schedule instead of per-consumer release notifications (HOSTING.md; notify workflow removed).