feat: package skills as per-skill Nix derivations (task 0001)

Add the content tier: a standalone flake that auto-discovers each skill (a directory containing a SKILL.md, at any depth) and exposes it as an individually addressable derivation built by lib.mkSkill. Directories without a SKILL.md are descended through as cosmetic containers; once a SKILL.md is found, that directory's subfolders are its assets, not further skills. Skill names must be globally unique across the tree — a collision is a hard eval-time error, not a warning. A fixture-driven skill-build check under `nix flake check` exercises the recursive walk, the builder, the SKILL.md-at-$out-root contract, the eval-time name passthru, and the collision error. The repo ships no real skill content yet, so packages.<system> is empty today.
2026-07-21 22:50:37 -04:00
parent 9068aa44f9
commit 8622b35f48
15 changed files with 416 additions and 0 deletions
--- a/flake.nix
+++ b/flake.nix
@@ -0,0 +1,55 @@
+{
+  description = "Personal agent skills, packaged through Nix.";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs =
+    { self, nixpkgs, flake-utils }:
+    let
+      mkSkill = import ./lib/mk-skill.nix;
+      discoverSkills = import ./lib/discover.nix nixpkgs.lib;
+
+      discoveredSkills = discoverSkills ./skills;
+
+      skillPackages =
+        pkgs:
+        nixpkgs.lib.listToAttrs (
+          map (skill: {
+            inherit (skill) name;
+            value = mkSkill { inherit pkgs; inherit (skill) name src; };
+          }) discoveredSkills
+        );
+    in
+    {
+      lib = { inherit mkSkill; };
+    }
+    //
+    # An explicit system list rather than `eachDefaultSystem`.
+    # That default set includes x86_64-darwin, which current nixpkgs no longer
+    # evaluates (its `legacyPackages` throws).
+    flake-utils.lib.eachSystem
+      [
+        "x86_64-linux"
+        "aarch64-linux"
+        "aarch64-darwin"
+      ]
+      (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          # No `default`: a catalog has no single default skill.
+          packages = skillPackages pkgs;
+
+          # Each discovered skill is folded in as its own check, so
+          # `nix flake check` builds every skill and fails on a malformed one.
+          checks = (skillPackages pkgs) // {
+            skill-build = import ./checks/skill-build.nix {
+              inherit pkgs mkSkill discoverSkills;
+            };
+          };
+        }
+      );
+}