Author the "Atrium" DEC — the live-layer-over-git co-working room (Yjs + self-hosted Y-Sweet; snapshot bridge → reconcile)

task-atrium-live-layer-over-git

task confidence inferred status done 2026-06-18 owner principal-architect

source log-auditor — surfaced recording 0052-agentic-agency-in-a-box-and-adoption-ladder, which names "Atrium" as the agency's live co-working room and lists it as an expected follow-on DEC ("the live-layer-over-git collaboration surface"). Board globbed before filing — no open task mentioned Atrium, Yjs, Y-Sweet, or a live-layer-over-git surface (grep confirmed 0 hits across knowledge/tasks/). Closed 2026-06-18, SATISFIED BY DEC-0054 (0054-atrium-live-layer-over-git) — the Atrium DEC was authored + recorded via the log-auditor; per board convention, writing the DEC fulfills this task.

Author the "Atrium" DEC — the live-layer-over-git co-working room

DONE (2026-06-18) — satisfied by DEC-0054. The Atrium DEC was authored and recorded via the log-auditor (per board convention, writing the DEC fulfills this task). It ratifies the engine (Yjs) + the sovereignty constraint (self-hosted Y-Sweet, one namespace per tenant, persist-to-git), specifies the snapshot bridge through reconcile() + OKF validation (malformed state rejected at the bridge), keeps git SSOT (Atrium = replaceable cache), and DEFERS the deployment host to an explicit human cost/ops sign-off before Phase 2 (the single new standing-cost commitment). The DEC itself carries confidence: asserted with its own Phase-0-implementation verification gate — but the authoring task is complete. Acceptance criteria annotated below.

One loop, three faces — ship an agentic Digital Experience Agency "in a box" (the Agency) plus an adoption-ladder readout product (the Ladder) over the OKF Company Brain, dogfood-first names "Atrium" as the agentic agency's co-working room — the place humans and the agent teams act on the live shared source of truth, under the approve/ship loop — and lists it as an expected follow-on DEC. This task is that DEC.

The work

Specify Atrium: the live collaboration layer over the git-resident OKF. Git stays the durable, owned, portable source of truth (Adopt OKF as Dossier's canonical knowledge format); Atrium is the ephemeral, real-time co-presence surface on top of it.

Proposed mechanism (to specify/ratify in the DEC):

Yjs CRDTs for the live shared document.
A self-hosted Y-Sweet (or equivalent) sync server — sovereignty: no third party holds the org's live state.
A snapshot bridge that materializes the live state into OKF atoms and runs it through reconcile() (The compounding merge — the per-tenant learning loop accumulates by id + confidence instead of overwriting (okf reconcile() + opt-in reconcile in extraction/runtime)) — so live edits compound into git-owned memory under the curation guard (confidence ladder; orphan→flag, never delete), exactly like an extraction pass.

Keep the SSOT invariant explicit: git is the source of truth; Atrium is a derived, replaceable live cache — the same OKF-philosophy stance the design system and the served site already take.

Why a task, not a fix-in-place

A net-new architecture surface with real sovereignty and mechanism trade-offs (hosted vs self-hosted sync, CRDT vs OT, snapshot cadence, approve-gating) — owner judgment for the Principal Platform Architect, not a hygiene fix. confidence: inferred (agent-filed from DEC-0052's named follow-up).

Coordinate, don't duplicate

Sibling of Author the agentic-agency runtime topology DEC + spec (OKF→persona/runbook/team; coordinator/dispatch; per-tenant fleet isolation; Atrium+board+reconcile+MCP composition), which composes Atrium with the board + reconcile + MCP into one governed loop (that task carries the ordering-hint dependency on this one). Board globbed before filing: no open task mentioned Atrium / Yjs / Y-Sweet / a live-layer-over-git surface.