# Session 0024.0 — Transcript

> App: vscode-cowriting-plugin
> Start: 2026-06-11T12-36 (PST) · End: 2026-06-11T12-50 (PST, approximate)
> Type: brainstorming
> Driver: Ben Stull (with Claude)
> Status: **FINALIZED (adopted)** — see the note below.

## Adoption note

This session ended **without finalizing** (it was left `--INPROGRESS`), so its
original turn-by-turn conversation was not preserved. It was **adopted and
finalized by session 0026's driver** on 2026-06-11 (per the finalize-on-goal /
adopt-and-finalize policy). The end time above is approximate — the session ended
sometime before session 0025 claimed at 12-51. The content below is **reconstructed**
from the artifact this session produced (the F8 Solution Design) and the project
memory written at the time, not from a live transcript.

## Launch prompt

```
Brainstorm and write the Solution Design for #25 (out-of-workspace authoring) —
settle the hybrid persistence model, the F5 cross-rung non-shareability, and the
URI-rename orphaning caveat; per the issue body.
```

## Output (the reviewed artifact)

The session produced and graduated the **F8 Solution Design**,
`specs/coauthoring-out-of-workspace.md` (submitted to the content repo's `specs/`
collection during this adopted finalize — it had not been submitted when the
session ended). Forks settled (per the spec §9 + memory):

- **Hybrid persistence (load-bearing):** a `SidecarStore` interface + `SidecarRouter`
  façade with two impls — repo-rooted `CoauthorStore` (in-workspace `file:` →
  committable `.threads/`, INV-2 byte-for-byte) and a new `GlobalSidecarStore`
  (out-of-workspace `file:` + `untitled:` → global storage by `sha256(uri)`,
  INV-19). Routed per-document by `#24`'s `isUnderRoot`. → INV-24.
- **F5 cross-rung non-shareability:** a global artifact isn't a committed file, so
  it is single-rung by construction. → INV-25.
- **URI-rename orphaning:** accepted & documented (inherent to URI-hash keying).
- **Document key** = repo-relative path in-workspace / URI string otherwise;
  shared `isAuthorable` gate; untitled in-memory only (no on-save migration in v1).

## Downstream

F8 was implemented from this design in **session 0025** (PR #26, shipped to `main`)
and the diff/preview authorship follow-up shaped F9 (session 0026, PR #27). See the
project memory `f8-out-of-workspace-spec-graduated` / `f8-out-of-workspace-shipped`.

## Deferred decisions

None recorded (the placeholder's section was empty; this is an adopted finalize, so
no new low-confidence calls were made here beyond the approximate end time).