diff --git a/docs/project-status.md b/docs/project-status.md
index 748af1f..b152d5b 100644
--- a/docs/project-status.md
+++ b/docs/project-status.md
@@ -4,6 +4,23 @@ Baseline: `c1ef2ee`. This review compares the live Gitea acceptance criteria wit
 source, tests, and recorded runtime evidence. Implementation is not milestone
 acceptance. The earlier assessment understated remaining M2/M3 work.
 
+## Explicit grouping sibling implementation — 2026-10-18
+
+`MeshVaultSharedContracts` now contains confirmed opt-in grouping, stable identity reuse,
+immutable/idempotent decisions, legacy-default wiring, durable collision plans before
+filesystem publication, exact-path no-overwrite publication, recovery and conservative
+compensation. Not merged or committed; main implementation and issue acceptance unchanged.
+
+Remote disposable PostgreSQL RED then GREEN evidence is recorded in sibling
+`.superpowers/shared-contracts/explicit-grouping-report.md`: final **483 tests,
+2776 assertions, 11 skips**, foundation and lint exit 0. Linux SQLite additionally passed
+483 tests / 2407 assertions / 44 skips. Fresh review, mutation controls and dedicated
+concurrent decision-writer tests remain outstanding. Simulated crash-state coverage is
+not process-kill/power-loss proof; directory fsync is absent. Uncertain compensation retains
+files. Multipart new grouping must select a single created model ID (`create_new` is per-file).
+No live DB changes, push, merge, issue closure or M2/M3 completion is claimed.
+
+
 ## Catalog-core Task 4 evidence — 2026-10-13
 
 Tasks 1–3 were approved at handoff (371 tests / 2032 assertions / 22 skips,