Fix plain-text email formatting

.surface

@@ -33,6 +33,7 @@ hey compose
 hey compose --bcc
 hey compose --cc
 hey compose --message
+hey compose --raw-html
 hey compose --subject
 hey compose --thread-id
 hey compose --to
@@ -62,6 +63,7 @@ hey recordings --limit
 hey recordings --starts-on
 hey reply
 hey reply --message
+hey reply --raw-html
 hey seen
 hey setup
 hey skill

internal/cmd/compose.go

@@ -19,6 +19,7 @@ type composeCommand struct {
 	subject  string
 	message  string
 	threadID string
+	rawHTML  bool
 }
 
 func newComposeCommand() *composeCommand {
@@ -27,12 +28,13 @@ func newComposeCommand() *composeCommand {
 		Use:   "compose",
 		Short: "Compose a new message",
 		Annotations: map[string]string{
-			"agent_notes": "Creates a new email. Requires --subject. Use --to (optionally with --cc/--bcc) for new threads or --thread-id for existing ones.",
+			"agent_notes": "Creates a new email. Requires --subject. Use --to (optionally with --cc/--bcc) for new threads or --thread-id for existing ones. Plain-text paragraphs and line breaks are preserved automatically; use --raw-html only when supplying HEY-compatible HTML.",
 		},
 		Example: `  hey compose --to alice@example.com --subject "Hello" -m "Hi there"
   hey compose --to alice@example.com --cc bob@example.com --bcc carol@example.org --subject "Hello" -m "Hi"
   hey compose --subject "Update" --thread-id 12345 -m "Thread reply"
-  echo "Long message" | hey compose --to bob@example.com --subject "Report"`,
+  echo "Long message" | hey compose --to bob@example.com --subject "Report"
+  hey compose --to bob@example.com --subject "Formatted" --raw-html -m "<p>Hello</p>"`,
 		RunE: composeCommand.run,
 	}
 
@@ -42,6 +44,7 @@ func newComposeCommand() *composeCommand {
 	composeCommand.cmd.Flags().StringVar(&composeCommand.subject, "subject", "", "Message subject (required)")
 	composeCommand.cmd.Flags().StringVarP(&composeCommand.message, "message", "m", "", "Message body (or opens $EDITOR)")
 	composeCommand.cmd.Flags().StringVar(&composeCommand.threadID, "thread-id", "", "Thread ID to post message to")
+	composeCommand.cmd.Flags().BoolVar(&composeCommand.rawHTML, "raw-html", false, "Send message body as HEY-compatible HTML without plain-text formatting")
 
 	return composeCommand
 }
@@ -79,6 +82,10 @@ func (c *composeCommand) run(cmd *cobra.Command, args []string) error {
 	}
 
 	ctx := cmd.Context()
+	message = formatMessageContent(message, c.rawHTML)
+	if message == "" {
+		return output.ErrUsage("empty message, aborting")
+	}
 
 	if c.threadID != "" {
 		topicID, err := strconv.ParseInt(c.threadID, 10, 64)

internal/cmd/message_format.go

@@ -0,0 +1,60 @@
+package cmd
+
+import (
+	"html"
+	"strings"
+)
+
+// formatMessageContent converts plain text into the HTML/Action Text content
+// expected by HEY. Without block markup, browsers collapse newlines and render
+// an entire plain-text message as a single paragraph.
+func formatMessageContent(message string, rawHTML bool) string {
+	if rawHTML {
+		if strings.TrimSpace(message) == "" {
+			return ""
+		}
+		return message
+	}
+
+	message = strings.ReplaceAll(message, "\r\n", "\n")
+	message = strings.ReplaceAll(message, "\r", "\n")
+	message = strings.TrimSpace(message)
+	if message == "" {
+		return ""
+	}
+
+	paragraphs := splitParagraphs(message)
+	formatted := make([]string, 0, len(paragraphs))
+	for _, paragraph := range paragraphs {
+		escaped := html.EscapeString(paragraph)
+		escaped = strings.ReplaceAll(escaped, "\n", "<br>")
+		formatted = append(formatted, "<p>"+escaped+"</p>")
+	}
+
+	return strings.Join(formatted, "\n")
+}
+
+func splitParagraphs(message string) []string {
+	lines := strings.Split(message, "\n")
+	paragraphs := make([]string, 0, len(lines))
+	current := make([]string, 0, 1)
+
+	flush := func() {
+		if len(current) == 0 {
+			return
+		}
+		paragraphs = append(paragraphs, strings.Join(current, "\n"))
+		current = current[:0]
+	}
+
+	for _, line := range lines {
+		if strings.TrimSpace(line) == "" {
+			flush()
+			continue
+		}
+		current = append(current, line)
+	}
+	flush()
+
+	return paragraphs
+}

internal/cmd/message_format_test.go

@@ -0,0 +1,58 @@
+package cmd
+
+import "testing"
+
+func TestFormatMessageContent(t *testing.T) {
+	tests := []struct {
+		name    string
+		message string
+		rawHTML bool
+		want    string
+	}{
+		{
+			name:    "separate paragraphs",
+			message: "Hello,\n\nSecond paragraph.\n\nRegards,\nIvan",
+			want:    "<p>Hello,</p>\n<p>Second paragraph.</p>\n<p>Regards,<br>Ivan</p>",
+		},
+		{
+			name:    "normalizes Windows newlines",
+			message: "First\r\n\r\nSecond\rThird",
+			want:    "<p>First</p>\n<p>Second<br>Third</p>",
+		},
+		{
+			name:    "escapes HTML in plain text",
+			message: `Use <p> & "quotes"`,
+			want:    "<p>Use &lt;p&gt; &amp; &#34;quotes&#34;</p>",
+		},
+		{
+			name:    "preserves explicit HTML",
+			message: "<p>Hello</p><ul><li>One</li></ul>",
+			rawHTML: true,
+			want:    "<p>Hello</p><ul><li>One</li></ul>",
+		},
+		{
+			name:    "rejects whitespace-only HTML",
+			message: " \n\t ",
+			rawHTML: true,
+			want:    "",
+		},
+		{
+			name:    "trims surrounding whitespace",
+			message: "\n\n Hello \n\n",
+			want:    "<p>Hello</p>",
+		},
+		{
+			name:    "rejects whitespace-only text",
+			message: " \n\t ",
+			want:    "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := formatMessageContent(tt.message, tt.rawHTML); got != tt.want {
+				t.Fatalf("formatMessageContent() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}

internal/cmd/reply.go

@@ -14,6 +14,7 @@ import (
 type replyCommand struct {
 	cmd     *cobra.Command
 	message string
+	rawHTML bool
 }
 
 func newReplyCommand() *replyCommand {
@@ -22,15 +23,17 @@ func newReplyCommand() *replyCommand {
 		Use:   "reply <thread-id>",
 		Short: "Reply to a thread",
 		Annotations: map[string]string{
-			"agent_notes": "Replies to the latest entry in a thread. Accepts message via -m, stdin, or $EDITOR.",
+			"agent_notes": "Replies to the latest entry in a thread. Accepts message via -m, stdin, or $EDITOR. Plain-text paragraphs and line breaks are preserved automatically; use --raw-html only when supplying HEY-compatible HTML.",
 		},
 		Example: `  hey reply 12345 -m "Thanks!"
-  echo "Detailed reply" | hey reply 12345`,
+  echo "Detailed reply" | hey reply 12345
+  hey reply 12345 --raw-html -m "<p>Thanks!</p>"`,
 		RunE: replyCommand.run,
 		Args: usageExactOneArg(),
 	}
 
 	replyCommand.cmd.Flags().StringVarP(&replyCommand.message, "message", "m", "", "Reply message (or opens $EDITOR)")
+	replyCommand.cmd.Flags().BoolVar(&replyCommand.rawHTML, "raw-html", false, "Send message body as HEY-compatible HTML without plain-text formatting")
 
 	return replyCommand
 }
@@ -90,6 +93,10 @@ func (c *replyCommand) run(cmd *cobra.Command, args []string) error {
 		}
 	}
 
+	message = formatMessageContent(message, c.rawHTML)
+	if message == "" {
+		return output.ErrUsage("empty message, aborting")
+	}
 	if err = sdk.Entries().CreateReply(ctx, latestEntryID, message, addressed.To, addressed.CC, addressed.BCC); err != nil {
 		return convertSDKError(err)
 	}