feat(canonical): validate profile name, apply env-var substitution before render

internal/cli/init.go

@@ -23,6 +23,7 @@ func NewInit(reg *adapter.Registry) *cobra.Command {
 		home     string
 		from     []string
 		noPrompt bool
+		force    bool
 	)
 	cmd := &cobra.Command{
 		Use:   "init",
@@ -42,6 +43,10 @@ func NewInit(reg *adapter.Registry) *cobra.Command {
 			if err = os.MkdirAll(r, 0o750); err != nil {
 				return err
 			}
+			// Issue 1: refuse overwrite without --force
+			if _, statErr := os.Stat(filepath.Join(r, "config.yaml")); statErr == nil && !force {
+				return fmt.Errorf("canonical root %s already initialised (use --force to re-import; existing skills/agents/mcp will be merged)", r)
+			}
 			candidates := reg.DetectedNames()
 			if len(candidates) == 0 {
 				return fmt.Errorf("no harnesses detected under %s", home)
@@ -77,6 +82,7 @@ func NewInit(reg *adapter.Registry) *cobra.Command {
 	cmd.Flags().StringVar(&home, "home", "", "home dir (default $HOME)")
 	cmd.Flags().StringSliceVar(&from, "from", nil, "import from specific adapter(s), skip prompt")
 	cmd.Flags().BoolVar(&noPrompt, "no-prompt", false, "import from all detected adapters without prompting")
+	cmd.Flags().BoolVar(&force, "force", false, "re-import even if canonical root already initialised")
 	return cmd
 }
 
@@ -153,6 +159,18 @@ func runImport(cmd *cobra.Command, reg *adapter.Registry, root, home string, pic
 	return nil
 }
 
+// importedProfileBody is the placeholder written to profiles/imported.yaml on first init.
+// Written using escape sequences to avoid literal newlines in string literals.
+const importedProfileBody = "# harness-sync profile \xe2\x80\x94 generated by init\n" +
+	"# Edit the gateway block below to point at your LLM gateway before running\n" +
+	"# `harness-sync apply`. The dummy token is fine for most local gateways.\n" +
+	"name: imported\n" +
+	"gateway:\n" +
+	"  url: \"\"                              # \xe2\x86\x90 set this\n" +
+	"  token: \"dummy\"\n" +
+	"  default_model: \"\"                    # \xe2\x86\x90 set this\n" +
+	"models: []\n"
+
 func writeCanonical(root string, b *canonical.Bundle, picked []string) error {
 	for _, sub := range []string{"profiles", "skills", "agents", "instructions"} {
 		if err := os.MkdirAll(filepath.Join(root, sub), 0o750); err != nil {
@@ -171,20 +189,12 @@ func writeCanonical(root string, b *canonical.Bundle, picked []string) error {
 		return err
 	}
 
-	profBody, err := render.YAML(canonical.Profile{
-		Name: "imported",
-		Gateway: canonical.Gateway{
-			URL:          "https://gateway.local",
-			Token:        "dummy",
-			DefaultModel: "claude-sonnet-4-6",
-		},
-		Models: []canonical.Model{{ID: "claude-sonnet-4-6", Alias: "sonnet"}},
-	})
-	if err != nil {
-		return err
-	}
-	if err = os.WriteFile(filepath.Join(root, "profiles", "imported.yaml"), profBody, 0o600); err != nil {
-		return err
+	// Issue 2: write placeholder profile only if it doesn't exist yet (preserve user edits on re-init).
+	profPath := filepath.Join(root, "profiles", "imported.yaml")
+	if _, statErr := os.Stat(profPath); os.IsNotExist(statErr) {
+		if err = os.WriteFile(profPath, []byte(importedProfileBody), 0o600); err != nil {
+			return err
+		}
 	}
 
 	if len(b.MCP.Servers) > 0 {