Add "aperture skills install" to generate agent skills

cmd/aperture/main.go

@@ -109,6 +109,12 @@ func gitCommitHeightInDir(dir string) string {
 }
 
 func main() {
+	// Subcommands are dispatched before flag.Parse so their own flag sets
+	// own everything after the subcommand name.
+	if len(os.Args) > 1 && os.Args[1] == "skills" {
+		os.Exit(runSkills(os.Args[2:]))
+	}
+
 	flag.Parse()
 
 	if *flagVersion {

cmd/aperture/skills.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/tailscale/aperture-cli/internal/clients"
+	"github.com/tailscale/aperture-cli/internal/config"
+	"github.com/tailscale/aperture-cli/internal/skills"
+)
+
+// runSkills handles "aperture skills <subcommand>" and returns the process exit
+// code.
+func runSkills(args []string) int {
+	if len(args) == 0 {
+		skillsUsage()
+		return 2
+	}
+
+	switch args[0] {
+	case "install":
+		return runSkillsInstall(args[1:])
+	case "-h", "--help", "help":
+		skillsUsage()
+		return 0
+	default:
+		fmt.Fprintf(os.Stderr, "aperture skills: unknown subcommand %q\n\n", args[0])
+		skillsUsage()
+		return 2
+	}
+}
+
+func skillsUsage() {
+	fmt.Fprint(os.Stderr, `Usage: aperture skills <subcommand>
+
+Subcommands:
+  install   Generate the aperture skill and install it for the agents on this machine
+
+Run "aperture skills install -h" for the install flags.
+`)
+}
+
+// runSkillsInstall generates the skill and installs it, reporting what was
+// written.
+func runSkillsInstall(args []string) int {
+	fs := flag.NewFlagSet("aperture skills install", flag.ContinueOnError)
+	project := fs.Bool("project", false, "install into the current directory instead of the home directory")
+	force := fs.Bool("force", false, "overwrite skill directories owned by another tool")
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+
+	g, err := config.Load()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "loading launcher config: %v\n", err)
+		return 1
+	}
+
+	var agents []skills.AgentInfo
+	for _, c := range clients.All(g) {
+		agents = append(agents, skills.AgentInfo{
+			Name:        c.Name(),
+			Binary:      c.BinaryName(),
+			InstallHint: c.Install(g).Hint,
+		})
+	}
+
+	// Best effort: the skill falls back to describing the per-OS locations
+	// when the config directory cannot be resolved.
+	var configDir string
+	if dir, err := os.UserConfigDir(); err == nil {
+		configDir = filepath.Join(dir, "aperture")
+	}
+
+	res, err := skills.Install(skills.Options{
+		Version: buildVersion,
+		Skills: skills.Content(skills.ContentParams{
+			Version:   buildVersion,
+			Endpoint:  g.ApertureHost,
+			Agents:    agents,
+			ConfigDir: configDir,
+		}),
+		Project: *project,
+		Force:   *force,
+	})
+	if err != nil {
+		// A conflict is the expected refusal, not a crash: print it plainly
+		// so the user can see which directories are in the way.
+		var conflict *skills.ConflictError
+		if errors.As(err, &conflict) {
+			fmt.Fprintln(os.Stderr, conflict.Error())
+			return 1
+		}
+		fmt.Fprintf(os.Stderr, "installing skill: %v\n", err)
+		return 1
+	}
+
+	fmt.Printf("Installed %d skills:\n", len(res.Skills))
+	for _, s := range res.Skills {
+		fmt.Printf("  %s\n    %s\n", s.Name, s.Canonical)
+		for _, l := range s.Linked {
+			fmt.Printf("    linked into %s: %s\n", l.Agent, l.Path)
+		}
+	}
+	for _, path := range res.Pruned {
+		fmt.Printf("  pruned %s\n", path)
+	}
+	for _, c := range res.Overwrote {
+		fmt.Printf("  overwrote %s (was owned by %s)\n", c.Path, c.Owner)
+	}
+	return 0
+}