refactor: centralize agent skills at ~/.agents/skills

modules/home-manager/coding/agents/default.nix

@@ -1,10 +1,39 @@
 # Per-tool agent sub-modules
 # Each module handles rendering canonical agent.toml definitions
 # for a specific AI coding tool.
+#
+# Also provides the shared coding.agents.skills submodule that writes
+# ~/.agents/skills — the central skills directory used by Pi, OpenCode, etc.
 {
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  shared = import ./shared-options.nix {inherit lib;};
+  cfg = config.coding.agents.skills;
+  mkIf = lib.mkIf;
+in {
   imports = [
     ./opencode.nix
     ./claude-code.nix
     ./pi.nix
   ];
+
+  options.coding.agents.skills = {
+    agentsInput = shared.mkAgentsInputOption ''
+      The `agents` flake input (your personal AGENTS repo).
+      When set, skills are symlinked to ~/.agents/skills.
+    '';
+
+    externalSkills = shared.externalSkillsOption;
+  };
+
+  config = mkIf (cfg.agentsInput != null) {
+    home.file.".agents/skills".source = cfg.agentsInput.lib.mkOpencodeSkills {
+      inherit pkgs;
+      customSkills = "${cfg.agentsInput}/skills";
+      externalSkills = shared.mapExternalSkills cfg.externalSkills;
+    };
+  };
 }

modules/home-manager/coding/agents/opencode.nix

@@ -17,8 +17,6 @@ in
       '';
 
       modelOverrides = shared.mkModelOverridesOption;
-
-      externalSkills = shared.externalSkillsOption;
     };
 
     config = mkIf config.coding.agents.opencode.enable {
@@ -34,18 +32,6 @@ in
           };
         };
 
-      # Skills (merged from personal AGENTS repo + optional external skills)
-      xdg.configFile."opencode/skills" = let
-        cfg = config.coding.agents.opencode;
-      in
-        mkIf (cfg.agentsInput != null) {
-          source = cfg.agentsInput.lib.mkOpencodeSkills {
-            inherit pkgs;
-            customSkills = "${cfg.agentsInput}/skills";
-            externalSkills = shared.mapExternalSkills cfg.externalSkills;
-          };
-        };
-
       # Static config dirs from AGENTS repo
       xdg.configFile."opencode/context" = let
         cfg = config.coding.agents.opencode;

modules/home-manager/coding/agents/pi.nix

@@ -15,7 +15,10 @@ in
 
       mcpServers = mkOption {
         type = types.attrsOf types.anything;
-        default = if mcpCfg != null then mcpCfg.servers else {};
+        default =
+          if mcpCfg != null
+          then mcpCfg.servers
+          else {};
         defaultText = literalExpression "config.programs.mcp.servers";
         description = ''
           MCP server configurations for Pi (pi-mcp-adapter).
@@ -41,8 +44,6 @@ in
         '';
       };
 
-      externalSkills = shared.externalSkillsOption;
-
       settings = mkOption {
         type = types.submodule {
           freeformType = types.attrsOf types.anything;
@@ -156,8 +157,11 @@ in
             then let
               filtered = filterNulls v;
             in
-              if filtered == {} then null else filtered
+              if filtered == {}
-            else v) attrs
+              then null
+              else filtered
+            else v)
+          attrs
         );
 
       piSettings = filterNulls cfg.settings;
@@ -177,8 +181,7 @@ in
       # Dynamic home.file entries for agent .md files
       agentFiles =
         if cfg.agentsInput != null
-        then
+        then let
-          let
           agentNames = builtins.attrNames cfg.agentsInput.lib.loadAgents;
         in
           builtins.listToAttrs (
@@ -213,15 +216,6 @@ in
 
         # ── Agents — pi-subagents .md files ────────────────────────────
         agentFiles
-
-        # ── Skills symlinked from AGENTS repo + external skills ────────
-        (mkIf (cfg.agentsInput != null) {
-          ".pi/agent/skills".source = cfg.agentsInput.lib.mkOpencodeSkills {
-            inherit pkgs;
-            customSkills = "${cfg.agentsInput}/skills";
-            externalSkills = shared.mapExternalSkills cfg.externalSkills;
-          };
-        })
       ];
     });
   }