Phase 4 cleanup: remove the vestigial sbx-kits/ redirect (ADR-0001)

[wz-gsa]

Summary

ADR-0001 (isolation) moved the four mixin kits from sbx-kits/ (schemaVersion "2") to the neutral acq-kits/ (hybrid/v1) tree and declared acq-kits/ the single source of truth, keeping sbx-kits/ only as a one-release redirect to be removed in a Phase 4 cleanup (ADR §Decision "One-release redirect"; §Consequences "Phase 4 cleanup: remove the sbx-kits/ redirect contents"). That Phase 4 was never filed as an issue. This is it.

Ownership: @mogul indicated he intends to do this cleanup — filing so it's tracked; his to drive. Not picking it up to avoid stepping on the work.

Why now

• The "one release" window is long past — patterns is at v1.7.0; the redirect landed ~v1.2.0.
• Nothing live consumes sbx-kits/. Verified across all three repos: Quickstart pins only acq-kits/ (acq.backends/common.sh: PATTERNS_KIT_DIR="integrations/isolation/acq-kits"), and there are no dir= / ref= / kit add / source: references to sbx-kits/ anywhere outside the redirect README and ADR-0001 itself.
• The two trees are currently byte-identical dupes (usai-provider opencode.jsonc + merge-global-config.mjs + sync-usai-models.mjs) — exactly the duplication ADR-0001 wanted eliminated. Deleting the redirect makes acq-kits/usai-provider/.../opencode.jsonc the sole canonical template carrying the // BEGIN/END GENERATED USAI MODELS model-injection markers, so "update the central config once, everyone consumes it" has no second copy to keep in sync.

Scope

• Remove integrations/isolation/sbx-kits/ (the four redirect kit dirs + the redirect README.md). Prefer git mv to deleteme/ per workspace convention if a staged removal is preferred over outright delete.
• Confirm no make/CI target, validator, or test references sbx-kits/ after removal (validate-kits.py scans acq-kits/).
• The acq/sbx drift-guard test added in PR1: kit-bundle provenance schema field + permission-preservation & acq/sbx drift-guard tests #273 / PR feat(kits): add bundle provenance schema + permission/drift guards (#273) #274 was an interim safeguard while both trees exist — remove it in this cleanup PR once the dupe is gone (it becomes moot).
• Record Phase 4 complete in ADR-0001; note the sbx-kits/ removal in CHANGELOG.

Pre-flight (safety)

Before deleting, do a quick external-consumer check (GitHub code search for forks/pins referencing agentic-coding-patterns/.../sbx-kits/). If any external pin is found, keep the redirect one more release and note it here. (Internal consumers: none.)

Related

• ADR-0001 §"Phase 4 cleanup"
• PR1: kit-bundle provenance schema field + permission-preservation & acq/sbx drift-guard tests #273 / PR feat(kits): add bundle provenance schema + permission/drift guards (#273) #274 (interim drift-guard to remove here)

Co-authored-by: OpenCode Agent william.zujkowski@gsa.gov