diff --git a/docs/plans/2026-08-14-launcher-campaign.md b/docs/plans/2026-08-14-launcher-campaign.md
index 1a104e65..ecb3620b 100644
--- a/docs/plans/2026-08-14-launcher-campaign.md
+++ b/docs/plans/2026-08-14-launcher-campaign.md
@@ -51,6 +51,32 @@ Parallelism guide: LA3/LA4 (launcher side) proceed alongside LA5–LA8 (client
 side) — different assemblies, no shared files. LA9/LA10 close the launcher
 side; LA11 closes the campaign.
 
+## Linux posture (binding — user decision 2026-08-14)
+
+Everything the launcher does must WORK ON LINUX in this campaign, except
+GUI client launches: the Linux graphical client is Slice L, parked at L1,
+resuming later ("ok we will do it later"). Concretely:
+
+- **Linux-shipping in LA:** the Avalonia launcher UI, profile CRUD +
+  0600-permission file, installer (manual DAT picker — the auto-detect
+  paths are Windows-only; `acdream-bake` is GL-free and runs on Linux),
+  updater (staged swap; Linux can replace a running binary but keep the
+  same staged-atomic flow), headless launches with plugins + login
+  commands, and the character probe.
+- **Launcher UX on Linux:** the `gui` / `guiSelect` launch modes render
+  disabled with an explicit "requires the Linux graphical client (Slice
+  L)" note — never a silent failure.
+- **Per-slice enforcement:** every slice touching Launcher.Core, Headless,
+  Runtime, Bake, or Platform runs its test projects on Linux (native
+  Ubuntu or WSL, matching the K-slice practice) before the slice is DONE;
+  LA4/LA9/LA10 additionally prove a real `linux-x64` self-contained
+  publish. LA11's connected-gate script gets a Linux section: launcher on
+  Ubuntu doing CRUD, probe, headless launch with plugin + login commands,
+  first-run install with a manual DAT path, and an update swap.
+- When Slice L later ships, the launcher's Linux GUI modes light up with
+  NO launcher changes (the session-config contract is host-agnostic) —
+  that expectation is part of LA's design acceptance.
+
 ## LA0 — `AcDream.Platform` extraction
 
 New BCL-only project `src/AcDream.Platform/` holding `ApplicationPathSet` +
diff --git a/docs/superpowers/specs/2026-08-14-launcher-campaign-design.md b/docs/superpowers/specs/2026-08-14-launcher-campaign-design.md
index 162778ff..a68527c5 100644
--- a/docs/superpowers/specs/2026-08-14-launcher-campaign-design.md
+++ b/docs/superpowers/specs/2026-08-14-launcher-campaign-design.md
@@ -45,6 +45,7 @@ Decided this session (2026-08-14):
 | Launcher ↔ client coupling | **Approach A: file-contract orchestrator** (config in, status events out; no game-protocol code in the launcher) |
 | Update feed | **GitHub Releases** (manifest.json + per-RID zips as release assets) |
 | Profile editing | **Full CRUD in the launcher UI** — add/edit/remove servers, accounts, passwords, per-character settings. The JSON file is storage (hand-editable as a bonus), never the required interface |
+| Linux scope | **Full launcher stack Linux-tested in LA** (launcher UI, install/update, headless + plugins + probe); GUI launches stay Windows-only until Slice L resumes later (user 2026-08-14). Launcher disables GUI modes on Linux with an explicit note |
 | Character enumeration | **On-demand probe**: launcher spawns the headless host in a probe mode (connect → `CharacterList` → status event → graceful disconnect BEFORE entering world → exit) and folds the roster into the profile store |
 
 Rejected: the launcher itself embedding Runtime/Core.Net to speak the