feat(flake): #134 — unstable.<pkg> in the downstream, one input, no hand pins

Nomarchy now carries a nixpkgs-unstable input and exposes it through
overlays.default as an `unstable` attrset: in the template's
`home.packages = with pkgs; [ … ]` a user writes `unstable.lmstudio`
and is done. Downstream stays one locked input; nomarchy-pull moves it.
lib.nix needed zero changes — mkFlake's pkgs already applies the
overlay. The import is plain and non-recursive, so configs that never
reference unstable. pay nothing beyond the input fetch; allowUnfree
mirrors the base set so the motivating lmstudio resolves.

Home packages are the supported surface (documented convention). Costs
stated in the README, not hidden: you own the pinned+unstable
combination; a second toolchain lands in your closure (~690 of ~4k
paths shared, measured on lmstudio); it moves when the lock moves.
Lock bumps now move two channels — VERIFICATION §5 and CONVENTIONS
updated accordingly. flake.lock gained exactly one node
(nixos-unstable @ 753cc8a); nothing else moved.

Verification: V1 — nix flake check --no-build green; new eval-only
checks.unstable-seam green (26.05pre vs 26.11pre lib.version, no
builds); template HM activation built via mkFlake with unstable.hello
enabled and its closure carries the unstable store path (pg2zfr… vs
pinned nm7p8w…). Implementation by a Sonnet subagent; design and
review on Fable.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -519,6 +519,17 @@ reload                          # exec zsh (reload the shell)
   line to slim the machine, uncomment an extra (a browser, email, full TeX
   Live), or add your own. No `nomarchy.apps.*` toggles — a package list is
   already its own opt-out, so the distro doesn't impose these or wrap them.
+- **A newer individual app (unstable channel, #134):** Nomarchy carries a
+  second, newer nixpkgs channel and exposes it as `unstable` through its
+  overlay, so any package can be taken from it by prefixing `unstable.` in
+  `home.packages` — e.g. `unstable.lmstudio` — with no second flake input of
+  your own to manage. Three costs, stated plainly: (a) **you own this
+  combination** — nothing upstream tests a pinned Nomarchy plus an unstable
+  app together; (b) an unstable package brings its own second toolchain into
+  your closure (measured: `unstable.lmstudio` shares only ~690 of ~4k store
+  paths with the pinned set); (c) it moves whenever the flake lock moves
+  (`nomarchy-pull`), not on its own schedule. Home packages only — that's
+  the supported surface, not `system.nix` or the module set.
 
 ## Roadmap & known issues
 

agent/BACKLOG.md

@@ -89,29 +89,6 @@ rofi#2317, and take the fix when a release carries it. If it is still open at
 the next lock bump, that is fine — nothing here rots meanwhile.
 *Last checked 2026-07-17: open, no maintainer response, no linked PR.*
 
-### 134. `unstable.<pkg>` in the downstream — decided, build it
-
-**Decided 2026-07-17 (Bernardo): Nomarchy carries the channel.** Add a
-`nixpkgs-unstable` input to the distro flake and expose it through
-`overlays.default` as an `unstable` attrset, so
-`home.packages = [ unstable.lmstudio ];` just works — downstream stays one
-locked input and `nomarchy-pull` still moves it. Scope is **home packages
-only**; no `unstable.*` surface in system.nix, no `stable.` synonym for now.
-The input rides in the eval unconditionally (an unused input still locks +
-fetches — accepted). Original diagnosis stands: `mkFlake` has no overlay
-seam and `homeConfigurations` uses mkFlake's own `pkgs`, so nothing short of
-the distro carrying the channel keeps the user out of `fetchTarball` pinning.
-
-Costs accepted with the ruling, to be stated in docs, not hidden: lock bumps
-now move two channels (VERIFICATION §5 full-checklist applies to both); a
-user who reaches for `unstable.` pays a second stdenv/glibc in their closure
-(measured: lmstudio shares only ~690 of ~3.7–4k paths); and nothing upstream
-tests pinned-Nomarchy + unstable-app together — the README needs an explicit
-"you own this combination" paragraph. Ship with a commented example in
-`templates/downstream/home.nix` (opt-in convention) and a README table note.
-Pass = flake check green + a V1 build of the template HM closure with one
-`unstable.` package enabled. Related: #133.
-
 ## LATER
 
 - **Wallpapers artifact split** (ROADMAP § Faster switches — decided,
@@ -312,7 +289,7 @@ decide. **Resolved** entries stay for history; agents treat them as closed.
   is promoted, a public binary cache (cachix) is the likely first step.
 - **#134 unstable packages** — build it: Nomarchy carries the
   `nixpkgs-unstable` input, `unstable.*` via the overlay, home-scope only.
-  Moved to NEXT with the full decided shape.
+  Shipped the same day (ROADMAP § `unstable.<pkg>` in the downstream).
 - **#114 greeter layouts** — document only: a VT has one keymap by design,
   so tuigreet cannot honour per-device layouts. Shipped as the README
   "Greeter keyboard layout" note + a RECOVERY.md pointer; entry deleted.

agent/CONVENTIONS.md

@@ -68,5 +68,7 @@ those, it probably shouldn't exist.
 - Commit style: `feat|fix|test|docs|chore(scope): summary`, body with
   what/why + verification tier + what remains. Bookkeeping (`agent/`
   updates) rides in the same commit as the change.
-- `flake.lock` moves only when the task *is* a lock bump, and only within
+- `flake.lock` moves only when the task *is* a lock bump. The release
-  the pinned release branches.
+  inputs stay within their pinned release branches; the `nixpkgs-unstable`
+  input (#134, feeds `unstable.*`) tracks `nixos-unstable` and bumps
+  together with the rest — never alone, never `nix flake update`.

agent/JOURNAL.md

@@ -19,6 +19,25 @@ Template:
 
 ---
 
+## 2026-07-17 — #134: `unstable.<pkg>` seam shipped
+- **Task:** BACKLOG #134 (NEXT, decided shape from this morning's triage).
+- **Did:** `nixpkgs-unstable` input + `unstable` attrset in
+  `overlays.default` (plain lazy import, allowUnfree mirrored);
+  `lib.nix` untouched by design — mkFlake's pkgs already applies the
+  overlay. Template opt-in comment (`unstable.lmstudio`), README costs
+  paragraph, `checks.unstable-seam` (eval-only), VERIFICATION §5 +
+  CONVENTIONS two-channel lock rules. Lock gained exactly one node
+  (nixos-unstable @ 753cc8a, 2026-07-15). Sonnet implemented; design +
+  review here.
+- **Verified:** V1 — flake check green; unstable-seam check green
+  (26.05pre vs 26.11pre lib.version); template HM activation built with
+  `unstable.hello` and its closure carries the unstable store path
+  (pg2zfr… vs pinned nm7p8w…).
+- **Pending:** nothing; Bernardo's real-world case is him adding
+  `unstable.lmstudio` to ~/.nomarchy/home.nix whenever he likes.
+- **Next suggestion:** queue is NEXT-empty save watches (#143/#146/#149);
+  NOW holds only the install-findings stub awaiting Bernardo's call.
+
 ## 2026-07-17 — #127 CLOSED: the brick was hypridle eating its own resume path
 - **Task:** BACKLOG #127 (NOW). Two Sonnet forensics passes over the machine's
   journal; interpretation, verdict and close-out here. Bernardo ruled: close +

agent/VERIFICATION.md

@@ -137,7 +137,10 @@ Maintenance follows the same ladder:
 - **Flake lock bumps**: treat as maximum-blast-radius changes. Build,
   boot the VM, run the full regression checklist, and do a visual
   spot-check of the session (themes can shift with upstream package
-  changes). Never merge a lock bump on "it evaluates".
+  changes). Never merge a lock bump on "it evaluates". Since #134 the
+  lock carries **two channels** (the release pin and the
+  `nixos-unstable` pin feeding `unstable.*`) — a bump moves both, and
+  this checklist applies to both.
 - **Theme imports / new themes**: import via `tools/import-palettes.py`,
   then the full §3 visual protocol; additionally verify the theme-switch
   round trip (into the new theme and back out).

docs/ROADMAP.md

@@ -493,6 +493,23 @@ Design/decision records and a running log of shipped work (items marked
   V2 by render, both heads + the password dialog, via the new
   `tools/plymouth-preview.sh`. V3 (a real docked boot/shutdown) is queued: the
   fake heads exist from the start, so the rig cannot resize a canvas.
+- ✓ **`unstable.<pkg>` in the downstream (#134, 2026-07-17):** Nomarchy now
+  carries a `nixpkgs-unstable` input and exposes it through
+  `overlays.default` as an `unstable` attrset — in the template's
+  `home.packages = with pkgs; [ … ]` a user writes `unstable.lmstudio` and
+  is done: one downstream input, still locked, still moved by
+  `nomarchy-pull`. `lib.nix` needed zero changes (mkFlake's pkgs already
+  applies the overlay). A plain non-recursive `import` keeps it lazy —
+  configs that never write `unstable.` pay nothing beyond the input fetch;
+  `allowUnfree` mirrors the base set so the motivating lmstudio resolves.
+  Home packages are the supported surface (documented convention — the
+  overlay is technically visible system-side, deliberately undocumented).
+  Costs stated in the README, not hidden: you own the combination, second
+  toolchain in the closure (~690 of ~4k paths shared), moves with the lock.
+  Lock bumps now move two channels — VERIFICATION §5 + CONVENTIONS updated.
+  V1: template HM activation built with `unstable.hello`, closure carries
+  the unstable store path; `checks.unstable-seam` (eval-only) guards the
+  seam permanently; lock diff added exactly the one node.
 - ✓ **The idle brick's CAUSE found (#127 closed, 2026-07-17):** the incident
   was misdated — it did not happen "before 12:51:34 Jul 15" (that boot was
   healthy all day and ended in a routine clean reboot); it ended the

flake.lock

@@ -196,6 +196,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1784120854,
+        "narHash": "sha256-KesHgItiZPgGX740axSiQLcIQ8D24MDqNpkKYWIek8k=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "753cc8a3a87467296ddd1fa93f0cc3e81120ee46",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nur": {
       "inputs": {
         "flake-parts": [
@@ -226,6 +242,7 @@
         "home-manager": "home-manager",
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs",
+        "nixpkgs-unstable": "nixpkgs-unstable",
         "stylix": "stylix"
       }
     },

flake.nix

@@ -4,6 +4,11 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
 
+    # Second, newer channel — exists solely to feed the `unstable.*` overlay
+    # seam (#134), so downstream can pick individual newer apps without a
+    # second flake input of their own.
+    nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixos-unstable";
+
     home-manager = {
       url = "github:nix-community/home-manager/release-26.05";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -27,7 +32,7 @@
     };
   };
 
-  outputs = { self, nixpkgs, home-manager, stylix, nixos-hardware, ... }:
+  outputs = { self, nixpkgs, nixpkgs-unstable, home-manager, stylix, nixos-hardware, ... }:
     let
       system = "x86_64-linux";
       username = "nomarchy"; # reference host only; downstream picks its own
@@ -79,6 +84,17 @@
       # the `nomarchy.stateFile` option — reading it stays pure.
 
       overlays.default = final: prev: {
+        # A second, newer channel for individual apps (#134) — e.g. lmstudio,
+        # whose fast-moving upstream a pinned nixpkgs lags. Plain `import`,
+        # deliberately NOT final-recursive: it evaluates only when a config
+        # actually references `unstable.something`, so checkouts that never
+        # write `unstable.` pay nothing for it. allowUnfree mirrors the base
+        # set (lib.nix) so unfree apps — lmstudio is the motivating case —
+        # resolve here too.
+        unstable = import nixpkgs-unstable {
+          inherit (prev.stdenv.hostPlatform) system;
+          config.allowUnfree = true;
+        };
         nomarchy-state-sync = final.callPackage ./pkgs/nomarchy-state-sync {
           # Presets baked into the package, so `nomarchy-state-sync list`
           # works on machines that don't check out this repo.
@@ -2268,6 +2284,22 @@
               )
             '';
           };
+
+          # #134: proves the `unstable.*` overlay seam exists and is really a
+          # second channel, without building anything from it — evaluation-only,
+          # so this stays cheap even though nixpkgs-unstable is a whole extra
+          # input. `pkgs` here already carries overlays.default (line ~35).
+          unstable-seam =
+            let
+              expect = cond: msg: nixpkgs.lib.assertMsg cond "unstable-seam: ${msg}";
+              ok =
+                expect (pkgs.unstable ? hello)
+                  "pkgs.unstable has no `hello` — the overlay attr is missing or broken"
+                && expect (pkgs.unstable.lib.version != pkgs.lib.version)
+                  ("pkgs.unstable.lib.version == pkgs.lib.version — this is the same "
+                    + "channel as the pinned nixpkgs, not a second one");
+            in
+            assert ok; pkgs.runCommand "nomarchy-unstable-seam" { } "touch $out";
         };
 
       # ─── Reference host ────────────────────────────────────────────

templates/downstream/home.nix

@@ -201,6 +201,8 @@
 
     # Local AI (Ollama is a service toggle in system.nix)
     # lmstudio                    # (unfree; large closure)
+    # unstable.lmstudio           # newer lmstudio from the unstable channel —
+    #                             # you own this combination (see README)
     # alpaca                      # GTK Ollama UI
   ];
 }