diff --git a/cmd/adopt.go b/cmd/adopt.go
index d8601e3..4b38c6a 100644
--- a/cmd/adopt.go
+++ b/cmd/adopt.go
@@ -12,17 +12,19 @@ import (
 )
 
 var adoptCmd = &cobra.Command{
-	Use:   "adopt [branch]",
+	Use:   "adopt <parent>",
 	Short: "Start tracking an existing branch",
-	Long:  `Start tracking an existing branch by setting its parent.`,
-	Args:  cobra.MaximumNArgs(1),
-	RunE:  runAdopt,
+	Long: `Start tracking an existing branch by setting its parent.
+
+By default, adopts the current branch. Use --branch to specify a different branch.`,
+	Args: cobra.ExactArgs(1),
+	RunE: runAdopt,
 }
 
-var adoptParentFlag string
+var adoptBranchFlag string
 
 func init() {
-	adoptCmd.Flags().StringVar(&adoptParentFlag, "parent", "", "parent branch")
+	adoptCmd.Flags().StringVar(&adoptBranchFlag, "branch", "", "branch to adopt (default: current branch)")
 	rootCmd.AddCommand(adoptCmd)
 }
 
@@ -39,10 +41,13 @@ func runAdopt(cmd *cobra.Command, args []string) error {
 
 	g := git.New(cwd)
 
-	// Determine branch to adopt
+	// Parent is the required positional argument
+	parent := args[0]
+
+	// Determine branch to adopt (from flag or current branch)
 	var branchName string
-	if len(args) > 0 {
-		branchName = args[0]
+	if adoptBranchFlag != "" {
+		branchName = adoptBranchFlag
 	} else {
 		branchName, err = g.CurrentBranch()
 		if err != nil {
@@ -60,12 +65,6 @@ func runAdopt(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("branch %q is already tracked", branchName)
 	}
 
-	// Determine parent
-	parent := adoptParentFlag
-	if parent == "" {
-		return fmt.Errorf("--parent is required")
-	}
-
 	// Validate parent is trunk or tracked
 	trunk, err := cfg.GetTrunk()
 	if err != nil {
diff --git a/e2e/adopt_orphan_test.go b/e2e/adopt_orphan_test.go
index 3d069fe..83e8ff9 100644
--- a/e2e/adopt_orphan_test.go
+++ b/e2e/adopt_orphan_test.go
@@ -11,8 +11,8 @@ func TestAdoptExistingBranch(t *testing.T) {
 	env.Git("checkout", "-b", "external-branch")
 	env.CreateCommit("external work")
 
-	// Adopt it with explicit parent
-	env.MustRun("adopt", "external-branch", "--parent", "main")
+	// Adopt it (current branch with main as parent)
+	env.MustRun("adopt", "main")
 
 	env.AssertStackParent("external-branch", "main")
 }
diff --git a/e2e/chaos_manual_git_test.go b/e2e/chaos_manual_git_test.go
index f7708b6..f432aca 100644
--- a/e2e/chaos_manual_git_test.go
+++ b/e2e/chaos_manual_git_test.go
@@ -38,8 +38,8 @@ func TestManualBranchCreate(t *testing.T) {
 		t.Errorf("manual branch should not be tracked, got parent %q", parent)
 	}
 
-	// Can adopt it into the stack
-	env.MustRun("adopt", "manual-branch", "--parent", "main")
+	// Can adopt it into the stack (current branch with main as parent)
+	env.MustRun("adopt", "main")
 	env.AssertStackParent("manual-branch", "main")
 
 	// Now it shows in log