{
  description = "AI agent skills for Claude Code and OpenCode";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs = { self, nixpkgs, flake-utils }:
    let
      # Home Manager module for deploying skills
      skillsModule = import ./modules/ai-skills.nix;
      
      # List of available skills
      availableSkills = [
        "bd-issue-tracking"
        "code-review"
        "doc-review"
        "niri-window-capture"
        "ops-review"
        "orch"
        "screenshot-latest"
        "spec-review"
        "tufte-press"
        "worklog"
        "update-spec-kit"
        "update-opencode"
        "web-search"
        "web-research"
      ];
    in
    flake-utils.lib.eachDefaultSystem
      (system:
        let
          pkgs = import nixpkgs { inherit system; };
        in
        {
          # Development shell for working on skills
          devShells.default = pkgs.mkShell {
            name = "ai-skills";
            packages = with pkgs; [
              bash
              shellcheck
              jq
            ];
            
            shellHook = ''
              echo "🤖 AI Skills development environment"
              echo "Available skills: ${builtins.concatStringsSep ", " availableSkills}"
              echo ""
              echo "Commands:"
              echo "  ./bin/deploy-skill.sh <name>  - Copy skill to dotfiles"
              echo "  bash -n skills/*/scripts/*.sh - Validate all scripts"
            '';
          };

          # Package individual skills for deployment
          packages = 
            let
              # Filter to only skills that exist
              existingSkills = builtins.filter 
                (name: builtins.pathExists (./skills + "/${name}"))
                availableSkills;
              
              individualSkills = builtins.listToAttrs (
                map (skillName: {
                  name = skillName;
                  value = pkgs.stdenv.mkDerivation {
                    name = "ai-skill-${skillName}";
                    src = ./skills + "/${skillName}";
                    
                    installPhase = ''
                      mkdir -p $out
                      cp -r . $out/
                      
                      # Make scripts executable
                      if [ -d $out/scripts ]; then
                        chmod +x $out/scripts/*.sh 2>/dev/null || true
                      fi
                    '';
                  };
                }) existingSkills
              );
            in
            individualSkills // {
              # All skills as a combined package
              all-skills = pkgs.symlinkJoin {
                name = "all-ai-skills";
                paths = builtins.attrValues individualSkills;
              };
            };
        })
    // {
      # Export the Home Manager module
      homeManagerModules.ai-skills = skillsModule;
      
      # Also export as nixosModules for compatibility
      nixosModules.ai-skills = skillsModule;
      
      # Export skills paths for direct use
      lib = {
        inherit availableSkills;

        # Helper to get skill path
        getSkillPath = skillName: ./skills/${skillName};

        # Helper to get all skill paths
        getAllSkillPaths = map (name: ./skills/${name}) availableSkills;

        # API Keys - Single Source of Truth
        # Used by both direnv stdlib and sops-nix configuration
        apiKeys = [ "openai" "google" "anthropic" "openrouter" ];

        # Generate direnv stdlib use_api_keys function
        mkDirenvStdlib = keys:
          let
            toEnvVar = key: {
              "openai" = "OPENAI_API_KEY";
              "google" = "GEMINI_API_KEY";
              "anthropic" = "ANTHROPIC_API_KEY";
              "openrouter" = "OPENROUTER_API_KEY";
            }.${key} or (builtins.throw "Unknown API key: ${key}");

            # Google key exports both GEMINI_API_KEY and GOOGLE_API_KEY
            mkExport = key:
              if key == "google" then ''
              [ -f /run/secrets/api_keys/${key} ] && export ${toEnvVar key}="$(cat /run/secrets/api_keys/${key})" && export GOOGLE_API_KEY="$GEMINI_API_KEY"''
              else ''
              [ -f /run/secrets/api_keys/${key} ] && export ${toEnvVar key}="$(cat /run/secrets/api_keys/${key})"'';
          in ''
            use_api_keys() {
              ${builtins.concatStringsSep "\n  " (map mkExport keys)}
            }
          '';

        # Generate sops-nix secrets attribute set
        mkSopsSecrets = { keys, owner, group ? "users" }:
          builtins.listToAttrs (map (key: {
            name = "api_keys/${key}";
            value = {
              mode = "0600";
              inherit owner group;
            };
          }) keys);
      };
    };
}