feat(nix): expose skill for project delivery

INSTALL.md

@@ -69,31 +69,32 @@ Use the module instead ([ADR 0020](.claude/adr/0020-home-manager-module-for-decl
 ```
 
 `programs.gitea-axi.enable` installs the CLI, always.
-The Claude Code context — the Agent Skill and the SessionStart hook — follows the harness: it is declared under a single toggle, `programs.gitea-axi.enableClaudeCodeIntegration`, on by default, and lands only when `programs.claude-code.enable` is also on.
+The Claude Code SessionStart hook follows the harness: it is declared under `programs.gitea-axi.enableClaudeCodeIntegration`, on by default, and lands only when `programs.claude-code.enable` is also on.
 Enable gitea-axi on a host without Claude Code and you get the CLI and nothing else — no assertion, no toggles to turn off.
 Importing the module without setting `enable` changes nothing at all.
 
 The hook is declared through `programs.claude-code`'s own settings option, so a configuration that already sets its own `settings.hooks.SessionStart` gets gitea-axi's merged in alongside rather than colliding.
-The Skill is written straight into Claude Code's skills directory, so it composes with your own skills whether you declare them as `programs.claude-code.skills.<name> = ...` or as a single path standing for a whole directory — there is no form you have to switch to.
+The Agent Skill is exposed as `packages.<system>.gitea-axi-skill` for project-local delivery through an agent-agnostic dev-shell helper.
 
 #### Options
 
 | Option | Default | Meaning |
 | --- | --- | --- |
 | `programs.gitea-axi.enable` | `false` | Install the CLI. |
-| `programs.gitea-axi.package` | your `pkgs`' build of the package | The package to install, or `null` to declare the context without the binary. |
-| `programs.gitea-axi.enableClaudeCodeIntegration` | `true` | Declare the Agent Skill and SessionStart hook when Claude Code is enabled. |
+| `programs.gitea-axi.package` | your `pkgs`' build of the package | The package to install, or `null` to declare the hook without the binary. |
+| `programs.gitea-axi.enableClaudeCodeIntegration` | `true` | Declare the SessionStart hook when Claude Code is enabled. |
 
-`package = null` declares the context without installing the binary — for instance when you install gitea-axi system-wide through `environment.systemPackages`.
-The hook records the bare name `gitea-axi` and lets `PATH` resolve it ([ADR 0019](.claude/adr/0019-hook-records-search-path-name.md)), so a binary installed anywhere on `PATH` satisfies it, and the Skill is still taken from the default build.
+`package = null` declares the hook without installing the binary — for instance when you install gitea-axi system-wide through `environment.systemPackages`.
+The hook records the bare name `gitea-axi` and lets `PATH` resolve it ([ADR 0019](.claude/adr/0019-hook-records-search-path-name.md)), so a binary installed anywhere on `PATH` satisfies it.
 
-Turn `enableClaudeCodeIntegration` off to keep the CLI declarative while writing the Skill and hook yourself with `setup`.
+Turn `enableClaudeCodeIntegration` off to keep the CLI declarative while writing the hook yourself with `setup`.
 
 #### What the module does not cover
 
-Only the Claude Code integration is declarative.
+Only the Claude Code SessionStart hook is declarative.
 The Codex and OpenCode files that `setup hooks` also writes have no home-manager module owning them, so gitea-axi does not write them declaratively either.
 On a declarative system those targets are unmanaged and therefore writable, so `gitea-axi setup hooks` still installs them.
+The Agent Skill is packaged for project-local delivery, not installed globally by this module.
 
 ## Verifying an install
 

checks/home-manager-module.nix

@@ -8,11 +8,11 @@
 # the file mechanism, only which files a generation contains. Building the home
 # files derivation needs neither the Claude Code binary nor a running agent.
 #
-# The configurations cover the composition risks the reshape introduced: the
-# Skill coexisting with an operator's own skills in both the attribute-set and
-# whole-directory forms, the explicit sibling-enable gate that keeps the Skill
-# off a host without Claude Code, and the hook merging into an operator's own
-# SessionStart list rather than replacing it.
+# The configurations cover the remaining composition risks: the explicit
+# sibling-enable gate that keeps the hook off a host without Claude Code, the
+# hook merging into an operator's own SessionStart list rather than replacing it,
+# and the Agent Skill staying out of global harness directories because project
+# dev shells deliver it through the agent-agnostic skills helper.
 {
   pkgs,
   home-manager,
@@ -20,25 +20,6 @@
   package,
 }:
 let
-  inherit (pkgs) lib;
-
-  # A skill the operator declares as their own, as one attribute-set entry. Its
-  # SKILL.md is what the attribute-set assertion looks for beside the module's.
-  operatorAttrSkill = pkgs.runCommandLocal "operator-attr-skill" { } ''
-    mkdir -p "$out"
-    printf '%s\n' "the operator's own attribute-set skill" > "$out/SKILL.md"
-  '';
-
-  # A whole directory of skills, one folder per skill, for the path form of the
-  # operator's own `programs.claude-code.skills`. The Claude Code module installs
-  # this recursively; the module's own nested Skill entry has to drop in beside
-  # its contents rather than collide with a single link over the directory.
-  operatorSkillsDir = pkgs.runCommandLocal "operator-skills-dir" { } ''
-    mkdir -p "$out/operator-dir-skill"
-    printf '%s\n' "the operator's own whole-directory skill" \
-      > "$out/operator-dir-skill/SKILL.md"
-  '';
-
   # A distinctive command so the merged-hook assertion can tell the operator's
   # own SessionStart hook apart from gitea-axi's in the generated settings.json.
   operatorHook = {
@@ -74,29 +55,18 @@ let
       ];
     }).config.home-files;
 
-  # An operator on Claude Code who declares their own skill as an attribute-set
-  # entry: the module's Skill and theirs must both land, each at its own name.
-  attrSetSkills = homeFiles {
-    programs.claude-code.enable = true;
-    # A store path (not a bare derivation): the skills value type takes a path,
-    # and a derivation would be read as the attribute-set branch of the option.
-    programs.claude-code.skills.operator-attr-skill = "${operatorAttrSkill}";
-  };
-
-  # An operator who declares their own skills as a whole directory (path form):
-  # the module's Skill lands beside the directory's contents. A regression to a
-  # non-recursive path-form install would fail this build as a file collision.
-  wholeDirSkills = homeFiles {
-    programs.claude-code.enable = true;
-    programs.claude-code.skills = "${operatorSkillsDir}";
-  };
-
-  # Claude Code disabled: the explicit sibling-enable gate must leave no
-  # gitea-axi Skill entry in the generation.
+  # Claude Code disabled: the sibling-enable gate in the Claude Code module must
+  # leave no settings file or Skill entry in the generation.
   claudeCodeOff = homeFiles {
     programs.claude-code.enable = false;
   };
 
+  # Claude Code enabled: the module contributes only the SessionStart hook, not
+  # a global Skill entry.
+  claudeCodeOn = homeFiles {
+    programs.claude-code.enable = true;
+  };
+
   # An operator with their own SessionStart hook: the module's hook must merge
   # into that list rather than replace it.
   mergedHook = homeFiles {
@@ -107,27 +77,22 @@ in
 pkgs.runCommandLocal "gitea-axi-home-manager-module-check"
   {
     # Forcing each derivation as a build input is what actually builds the home
-    # files tree under every configuration; the whole-directory build would fail
-    # here, before any assertion runs, on a non-recursive-install regression.
+    # files tree under every configuration.
     inherit
-      attrSetSkills
-      wholeDirSkills
       claudeCodeOff
+      claudeCodeOn
       mergedHook
       ;
   }
   ''
-    echo "attribute-set skills: module's Skill and operator's both land"
-    test -f "$attrSetSkills/.claude/skills/gitea-axi/SKILL.md"
-    test -f "$attrSetSkills/.claude/skills/operator-attr-skill/SKILL.md"
-
-    echo "whole-directory skills: module's Skill lands beside the directory"
-    test -f "$wholeDirSkills/.claude/skills/gitea-axi/SKILL.md"
-    test -f "$wholeDirSkills/.claude/skills/operator-dir-skill/SKILL.md"
-
-    echo "Claude Code disabled: no gitea-axi Skill entry is written"
+    echo "Claude Code disabled: no hook settings or global Skill entry is written"
+    test ! -e "$claudeCodeOff/.claude/settings.json"
     test ! -e "$claudeCodeOff/.claude/skills/gitea-axi"
 
+    echo "Claude Code enabled: hook lands, but the Skill is not globally installed"
+    grep -q '"gitea-axi"' "$claudeCodeOn/.claude/settings.json"
+    test ! -e "$claudeCodeOn/.claude/skills/gitea-axi"
+
     echo "operator's own SessionStart hook: the module's hook merges in"
     # Match the commands as quoted JSON string values, not by their position or
     # the emitter's colon spacing: both must be present for a merge (rather than

flake.nix

@@ -47,6 +47,15 @@
       packages = forAllSystems (
         { pkgs, ... }: rec {
           gitea-axi = pkgs.callPackage ./package.nix { };
+          gitea-axi-skill = pkgs.runCommandLocal "gitea-axi-skill"
+            {
+              passthru.skillName = "gitea-axi";
+            }
+            ''
+              mkdir -p "$out"
+              cp -R ${gitea-axi.skill}/. "$out/"
+              test -f "$out/SKILL.md"
+            '';
           default = gitea-axi;
         }
       );

home-manager-module.nix

@@ -1,17 +1,9 @@
-# A home-manager module installing gitea-axi and, when a harness is present,
-# its ambient context — the bundled Agent Skill and the SessionStart hook
-# (ADR 0020, reshaped by ADR 0021).
+# A home-manager module installing gitea-axi and, when Claude Code is present,
+# its SessionStart hook.
 #
-# `programs.gitea-axi.enable` installs the CLI, always. The Claude Code context
-# follows the harness: it is declared under one per-harness toggle and lands
-# only when `programs.claude-code.enable` is also on. gitea-axi is a working CLI
-# without a harness, so enabling it on a host with no Claude Code installs the
-# binary and nothing else, with no assertion.
-#
-# The module is a wiring layer and nothing more. Both artefacts come from the
-# package's published attributes, so what a declarative configuration installs
-# and what `gitea-axi setup` writes imperatively are the same two artefacts, and
-# neither is restated here.
+# `programs.gitea-axi.enable` installs the CLI, always.
+# The Agent Skill is exposed as a package output for agent-agnostic delivery by
+# a project's dev shell or an operator's shared skill delivery module.
 #
 # Importing this module changes nothing until `programs.gitea-axi.enable` is set.
 {
@@ -24,15 +16,13 @@ let
   cfg = config.programs.gitea-axi;
 
   # The package the declarations are read out of. `package = null` opts out of
-  # putting the binary on PATH, not out of the configuration — an operator who
-  # installs gitea-axi system-wide still wants the Skill — so the declarations
+  # putting the binary on PATH, not out of the hook declaration — an operator who
+  # installs gitea-axi system-wide still wants the hook — so the declarations
   # fall back to the default build, which in that arrangement is already in the
   # closure anyway.
   sourcePackage = if cfg.package != null then cfg.package else defaultPackage;
 
   defaultPackage = pkgs.callPackage ./package.nix { };
-
-  claudeCode = config.programs.claude-code;
 in
 {
   options.programs.gitea-axi = {
@@ -44,12 +34,11 @@ in
       defaultText = lib.literalExpression "pkgs.callPackage ./package.nix { }";
       description = ''
         The gitea-axi package to install, or `null` to declare the ambient
-        context without installing the binary — for an operator who supplies it
-        another way, such as `environment.systemPackages`.
+        Claude Code hook without installing the binary — for an operator who
+        supplies it another way, such as `environment.systemPackages`.
 
         The SessionStart hook records a name resolved on `PATH`, so a binary
-        installed elsewhere satisfies it. With `null` the Agent Skill is still
-        taken from the default build.
+        installed elsewhere satisfies it.
       '';
     };
 
@@ -57,16 +46,15 @@ in
       type = lib.types.bool;
       default = true;
       description = ''
-        Whether to declare gitea-axi's Claude Code context — the bundled Agent
-        Skill and the SessionStart hook — alongside the CLI.
+        Whether to declare gitea-axi's Claude Code SessionStart hook alongside
+        the CLI.
 
-        Both artefacts land only when `programs.claude-code.enable` is also on;
-        with it off they are silently absent, matching how home-manager's own
+        The hook lands only when `programs.claude-code.enable` is also on;
+        with it off it is silently absent, matching how home-manager's own
         `enableBashIntegration`-style toggles behave against a disabled sibling.
 
         Turn this off to install gitea-axi declaratively while writing the
-        Claude Code context by hand or with `gitea-axi setup`. The toggle
-        generalises: a future harness reads as `enableCodexIntegration`.
+        Claude Code hook by hand or with `gitea-axi setup`.
       '';
     };
   };
@@ -75,44 +63,13 @@ in
     lib.mkMerge [
       (lib.mkIf (cfg.package != null) { home.packages = [ cfg.package ]; })
 
-      # The two Claude Code artefacts move together under one per-harness
-      # toggle. They are gated by different mechanisms internally — the Skill by
-      # an explicit `claude-code.enable` condition, the hook by the Claude Code
-      # module's own gate — because of how each is declared, below.
-      (lib.mkIf cfg.enableClaudeCodeIntegration (
-        lib.mkMerge [
+      (lib.mkIf cfg.enableClaudeCodeIntegration {
         # The hook is declared through the Claude Code module's own settings
         # option. That composes it with an operator's own SessionStart hooks
         # instead of colliding, and the module drops the declaration for free
-          # when it is disabled — so no explicit `claude-code.enable` gate here.
-          { programs.claude-code.settings.hooks.SessionStart = [ sourcePackage.sessionStartHook ]; }
-
-          # The Skill is written as an ordinary file into Claude Code's skills
-          # directory, rather than contributed to `programs.claude-code.skills`.
-          # That composes with both forms of the operator's own skills option —
-          # an attribute set and a single path for a whole directory — because
-          # it never touches that option's type, so the path-form collision
-          # disappears at its root instead of being escaped by a toggle.
-          #
-          # Writing through home.file does not inherit the Claude Code module's
-          # `enable`-gate the way declaring through its options does, so the
-          # Skill is gated on `claude-code.enable` explicitly. The gate is also
-          # what keeps package realisation lazy: home.file reads the Skill's
-          # source directory while evaluating, so an ungated write would realise
-          # the package on every host — even one with no Claude Code that
-          # installs nothing from it.
-          #
-          # `configDir` is read from the Claude Code module rather than
-          # hardcoded, so the Skill lands beside that module's own skills
-          # wherever the operator points it.
-          (lib.mkIf claudeCode.enable {
-            home.file."${claudeCode.configDir}/skills/gitea-axi" = {
-              source = sourcePackage.skill;
-              recursive = true;
-            };
+        # when it is disabled.
+        programs.claude-code.settings.hooks.SessionStart = [ sourcePackage.sessionStartHook ];
       })
     ]
-      ))
-    ]
   );
 }

package.nix

@@ -179,9 +179,10 @@ buildNpmPackage (finalAttrs: {
     # different majors.
     inherit nodejs;
 
-    # The bundled Agent Skill's directory, for a configuration that installs it
-    # declaratively. A directory rather than the SKILL.md inside it, so a Skill
-    # that grows helper files stays one reference.
+    # The bundled Agent Skill's directory, for a configuration that packages it
+    # into an agent-agnostic project-local delivery mechanism. A directory rather
+    # than the SKILL.md inside it, so a Skill that grows helper files stays one
+    # reference.
     skill = "${finalAttrs.finalPackage}/${skillSubdir}";
 
     # The SessionStart hook entry, verbatim as it belongs in a Claude Code