feat: add mail draft subcommand

internal/cmd/mail.go

@@ -11,9 +11,10 @@ import (
 )
 
 type MailCmd struct {
-	List MailListCmd `cmd:"" help:"List messages"`
-	Get  MailGetCmd  `cmd:"" help:"Get message by ID"`
-	Send MailSendCmd `cmd:"" help:"Send a new message"`
+	List  MailListCmd  `cmd:"" help:"List messages"`
+	Get   MailGetCmd   `cmd:"" help:"Get message by ID"`
+	Send  MailSendCmd  `cmd:"" help:"Send a new message"`
+	Draft MailDraftCmd `cmd:"" help:"Create a draft message"`
 }
 
 type MailListCmd struct {
@@ -148,6 +149,59 @@ func (c *MailSendCmd) Run(ctx context.Context) error {
 	return nil
 }
 
+type MailDraftCmd struct {
+	To      []string `name:"to" help:"Recipient email (repeat or comma-separate)"`
+	Subject string   `name:"subject" required:"" help:"Email subject"`
+	Body    string   `name:"body" help:"Plain text body"`
+	User    string   `name:"user" help:"App-only target user override (UPN or user ID)"`
+	DryRun  bool     `name:"dry-run" help:"Preview draft creation without saving"`
+}
+
+func (c *MailDraftCmd) Run(ctx context.Context) error {
+	rt, err := resolveRuntime(ctx, capMailDraft)
+	if err != nil {
+		return err
+	}
+	targetUser, err := resolveAppOnlyTargetUser(rt.Profile, c.User)
+	if err != nil {
+		return err
+	}
+
+	recipients := splitCSV(c.To)
+
+	if c.DryRun {
+		if outfmt.IsJSON(ctx) {
+			return outfmt.WriteJSON(os.Stdout, map[string]any{
+				"dry_run":  true,
+				"action":   "mail.draft",
+				"to":       recipients,
+				"subject":  c.Subject,
+				"body_len": len(c.Body),
+			})
+		}
+		if len(recipients) > 0 {
+			fmt.Fprintf(os.Stdout, "Dry run: would create draft to %s with subject %q\n", strings.Join(recipients, ", "), c.Subject)
+		} else {
+			fmt.Fprintf(os.Stdout, "Dry run: would create draft with subject %q (no recipients)\n", c.Subject)
+		}
+		return nil
+	}
+
+	svc := mail.New(rt.Graph, targetUser)
+	result, err := svc.Draft(ctx, recipients, c.Subject, strings.TrimSpace(c.Body))
+	if err != nil {
+		return err
+	}
+
+	if outfmt.IsJSON(ctx) {
+		return outfmt.WriteJSON(os.Stdout, result)
+	}
+
+	id := stringValue(result["id"])
+	fmt.Fprintf(os.Stdout, "Draft created (id: %s)\n", id)
+	return nil
+}
+
 func splitCSV(values []string) []string {
 	out := make([]string, 0)
 	seen := map[string]struct{}{}

internal/cmd/mail_test.go

@@ -29,6 +29,55 @@ func TestMailSendQuoteFlagParsesWithoutBody(t *testing.T) {
 	}
 }
 
+func TestMailDraftFlagParsesWithoutTo(t *testing.T) {
+	parser, cli, err := newParser("test")
+	if err != nil {
+		t.Fatalf("newParser failed: %v", err)
+	}
+
+	args := []string{
+		"mail", "draft",
+		"--subject", "Draft subject",
+		"--body", "Draft body",
+	}
+	if _, err := parser.Parse(args); err != nil {
+		t.Fatalf("parse failed: %v", err)
+	}
+
+	if cli.Mail.Draft.Subject != "Draft subject" {
+		t.Fatalf("unexpected subject: %q", cli.Mail.Draft.Subject)
+	}
+	if cli.Mail.Draft.Body != "Draft body" {
+		t.Fatalf("unexpected body: %q", cli.Mail.Draft.Body)
+	}
+	if len(cli.Mail.Draft.To) != 0 {
+		t.Fatalf("expected no recipients, got %v", cli.Mail.Draft.To)
+	}
+}
+
+func TestMailDraftFlagParsesWithTo(t *testing.T) {
+	parser, cli, err := newParser("test")
+	if err != nil {
+		t.Fatalf("newParser failed: %v", err)
+	}
+
+	args := []string{
+		"mail", "draft",
+		"--to", "a@example.com,b@example.com",
+		"--subject", "Draft subject",
+	}
+	if _, err := parser.Parse(args); err != nil {
+		t.Fatalf("parse failed: %v", err)
+	}
+
+	if len(cli.Mail.Draft.To) == 0 {
+		t.Fatalf("expected recipients, got none")
+	}
+	if cli.Mail.Draft.Subject != "Draft subject" {
+		t.Fatalf("unexpected subject: %q", cli.Mail.Draft.Subject)
+	}
+}
+
 func TestComposeQuotedReplyBodyAppendsQuoteBlock(t *testing.T) {
 	source := map[string]any{
 		"sentDateTime": "2026-02-18T13:00:00Z",

internal/cmd/runtime.go

@@ -24,6 +24,7 @@ const (
 	capMailList       runtimeCapability = "mail.list"
 	capMailGet        runtimeCapability = "mail.get"
 	capMailSend       runtimeCapability = "mail.send"
+	capMailDraft      runtimeCapability = "mail.draft"
 	capCalendarList   runtimeCapability = "calendar.list"
 	capCalendarGet    runtimeCapability = "calendar.get"
 	capCalendarCreate runtimeCapability = "calendar.create"
@@ -69,6 +70,7 @@ var capabilityRules = map[runtimeCapability]capabilityRule{
 	capMailList:       delegatedOrAppOnlyRule(),
 	capMailGet:        delegatedOrAppOnlyRule(),
 	capMailSend:       delegatedOrAppOnlyRule(),
+	capMailDraft:      delegatedOrAppOnlyRule(),
 	capCalendarList:   delegatedOnlyRule(calendarAppOnlyMessage),
 	capCalendarGet:    delegatedOnlyRule(calendarAppOnlyMessage),
 	capCalendarCreate: delegatedOnlyRule(calendarAppOnlyMessage),

internal/services/mail/service.go

@@ -13,6 +13,7 @@ import (
 var listMailScopes = []string{"Mail.Read"}
 var getMailScopes = []string{"Mail.Read"}
 var sendMailScopes = []string{"Mail.Send"}
+var draftMailScopes = []string{"Mail.ReadWrite"}
 
 type Service struct {
 	client      *graph.Client
@@ -93,6 +94,32 @@ func (s *Service) Send(ctx context.Context, to []string, subject string, body st
 	return err
 }
 
+func (s *Service) Draft(ctx context.Context, to []string, subject string, body string) (map[string]any, error) {
+	toRecipients := make([]map[string]any, 0, len(to))
+	for _, address := range to {
+		address = strings.TrimSpace(address)
+		if address == "" {
+			continue
+		}
+		toRecipients = append(toRecipients, map[string]any{
+			"emailAddress": map[string]any{"address": address},
+		})
+	}
+
+	payload := map[string]any{
+		"subject": subject,
+		"body": map[string]any{
+			"contentType": "Text",
+			"content":     body,
+		},
+		"toRecipients": toRecipients,
+	}
+
+	var result map[string]any
+	err := s.client.DoJSON(ctx, http.MethodPost, s.messagesEndpoint(), nil, payload, draftMailScopes, &result)
+	return result, err
+}
+
 func (s *Service) messagesEndpoint() string {
 	if s.appOnlyUser != "" {
 		return "/users/" + url.PathEscape(s.appOnlyUser) + "/messages"