fix(ui): wrap reasoning blocks to terminal width to prevent clipping

- wrap thinking text in StreamComponent and render.ReasoningBlock
- plumb width through renderer and streaming item paths
- keeps style consistent with user/assistant blocks and avoids cut-off lines

internal/ui/message_items.go

@@ -156,7 +156,7 @@ func (s *StreamingMessageItem) Render(width int) string {
 			durationMs = time.Since(s.startTime).Milliseconds()
 		}
 		ty := createTypography(style.GetTheme())
-		rendered = render.ReasoningBlock(s.content, durationMs, ty, style.GetTheme())
+		rendered = render.ReasoningBlock(s.content, durationMs, width, ty, style.GetTheme())
 	} else {
 		// Render as assistant message
 		rendered = render.AssistantBlock(s.content, width, style.GetTheme())

internal/ui/messages.go

@@ -178,7 +178,7 @@ func (r *MessageRenderer) RenderAssistantMessage(content string, timestamp time.
 // as live streaming: muted italic text with margin. This is used when resuming
 // sessions to display saved reasoning content.
 func (r *MessageRenderer) RenderReasoningBlock(content string, timestamp time.Time) UIMessage {
-	rendered := render.ReasoningBlock(content, 0, r.ty, style.GetTheme())
+	rendered := render.ReasoningBlock(content, 0, r.width, r.ty, style.GetTheme())
 
 	return UIMessage{
 		Type:      AssistantMessage,

internal/ui/render/blocks.go

@@ -63,14 +63,19 @@ func AssistantBlock(content string, width int, theme style.Theme) string {
 
 // ReasoningBlock renders a reasoning/thinking block with muted italic text.
 // If duration > 0, shows "Thought for Xs" label. Otherwise shows just "Thought".
-func ReasoningBlock(content string, duration int64, ty *herald.Typography, theme style.Theme) string {
+// The width parameter controls soft-wrapping so long reasoning lines don't get cut off.
+func ReasoningBlock(content string, duration int64, width int, ty *herald.Typography, theme style.Theme) string {
 	if strings.TrimSpace(content) == "" {
 		return ""
 	}
 
-	// Match live streaming styling: muted italic text
+	// Match live streaming styling: muted italic text. Wrap before styling so
+	// ANSI sequences from italics don't interfere with width calculations.
 	lines := strings.Split(strings.TrimRight(content, "\n"), "\n")
 	contentStr := strings.TrimLeft(strings.Join(lines, "\n"), " \t\n")
+	if width > 4 { // mirror other blocks (User/Assistant) which subtract 4
+		contentStr = lipgloss.Wrap(contentStr, width-4, "")
+	}
 	mutedStyle := lipgloss.NewStyle().Foreground(theme.Muted)
 	contentRendered := mutedStyle.Render(ty.Italic(contentStr))
 

internal/ui/stream.go

@@ -472,6 +472,10 @@ func (s *StreamComponent) renderReasoningBlock(reasoning string) string {
 
 	// Main content using Italic with Muted color for visual distinction.
 	content := strings.TrimLeft(strings.Join(lines, "\n"), " \t\n")
+	// Soft-wrap to the available width so long lines don't get cut off.
+	if s.width > 4 {
+		content = lipgloss.Wrap(content, s.width-4, "")
+	}
 	theme := GetTheme()
 	mutedStyle := lipgloss.NewStyle().Foreground(theme.Muted)
 	parts = append(parts, mutedStyle.Render(s.ty.Italic(content)))