diff --git a/crates/chattyness-user-ui/src/components/avatar_canvas.rs b/crates/chattyness-user-ui/src/components/avatar_canvas.rs
index ab5a0a9..71772f9 100644
--- a/crates/chattyness-user-ui/src/components/avatar_canvas.rs
+++ b/crates/chattyness-user-ui/src/components/avatar_canvas.rs
@@ -14,6 +14,28 @@ use super::chat_types::{emotion_bubble_colors, ActiveBubble};
 /// Base text size multiplier. Text at 100% slider = base_sizes * 1.4
 const BASE_TEXT_SCALE: f64 = 1.4;
 
+/// Estimate bubble height based on actual text content.
+/// Returns the total height including padding, tail, and gap.
+fn estimate_bubble_height(text: &str, text_scale: f64) -> f64 {
+    let max_bubble_width = 200.0 * text_scale;
+    let padding = 8.0 * text_scale;
+    let line_height = 16.0 * text_scale;
+    let tail_size = 8.0 * text_scale;
+    let gap = 5.0 * text_scale;
+
+    // Estimate chars per line: roughly 6 pixels per char at default scale
+    let chars_per_line = ((max_bubble_width - padding * 2.0) / (6.0 * text_scale)).floor() as usize;
+    let chars_per_line = chars_per_line.max(10); // minimum 10 chars per line
+    let char_count = text.len();
+
+    // Simple heuristic: estimate lines based on character count
+    let estimated_lines = ((char_count as f64) / (chars_per_line as f64)).ceil() as usize;
+    let estimated_lines = estimated_lines.clamp(1, 4); // 1-4 lines max
+
+    let bubble_height = (estimated_lines as f64) * line_height + padding * 2.0;
+    bubble_height + tail_size + gap
+}
+
 /// Content bounds for a 3x3 avatar grid.
 /// Tracks which rows/columns contain actual content for centering calculations.
 struct ContentBounds {
@@ -86,6 +108,89 @@ impl ContentBounds {
     fn empty_top_rows(&self) -> usize {
         self.min_row
     }
+
+    /// Width of actual content in pixels.
+    fn content_width(&self, cell_size: f64) -> f64 {
+        (self.max_col - self.min_col + 1) as f64 * cell_size
+    }
+
+    /// Height of actual content in pixels.
+    fn content_height(&self, cell_size: f64) -> f64 {
+        (self.max_row - self.min_row + 1) as f64 * cell_size
+    }
+}
+
+/// Computed boundaries for visual clamping in screen space.
+#[derive(Clone, Copy)]
+struct ScreenBoundaries {
+    /// Left edge of drawable area (= offset_x)
+    min_x: f64,
+    /// Right edge (= offset_x + scene_width * scale_x)
+    max_x: f64,
+    /// Top edge (= offset_y)
+    min_y: f64,
+    /// Bottom edge (= offset_y + scene_height * scale_y)
+    max_y: f64,
+}
+
+impl ScreenBoundaries {
+    fn from_transform(
+        scene_width: f64,
+        scene_height: f64,
+        scale_x: f64,
+        scale_y: f64,
+        offset_x: f64,
+        offset_y: f64,
+    ) -> Self {
+        Self {
+            min_x: offset_x,
+            max_x: offset_x + (scene_width * scale_x),
+            min_y: offset_y,
+            max_y: offset_y + (scene_height * scale_y),
+        }
+    }
+
+    /// Clamp avatar center so visual bounds stay within screen boundaries.
+    fn clamp_avatar_center(
+        &self,
+        center_x: f64,
+        center_y: f64,
+        half_width: f64,
+        half_height: f64,
+    ) -> (f64, f64) {
+        let clamped_x = center_x.max(self.min_x + half_width).min(self.max_x - half_width);
+        let clamped_y = center_y.max(self.min_y + half_height).min(self.max_y - half_height);
+        (clamped_x, clamped_y)
+    }
+}
+
+/// Position of speech bubble relative to avatar.
+#[derive(Clone, Copy, PartialEq)]
+enum BubblePosition {
+    /// Default: bubble above avatar
+    Above,
+    /// When near top edge: bubble below avatar
+    Below,
+}
+
+/// Determine bubble position based on available space above avatar.
+fn determine_bubble_position(
+    avatar_screen_y: f64,
+    avatar_half_height: f64,
+    bubble_height: f64,
+    tail_size: f64,
+    gap: f64,
+    min_y: f64,
+) -> BubblePosition {
+    let space_needed = bubble_height + tail_size + gap;
+    let avatar_top = avatar_screen_y - avatar_half_height;
+    let space_available = avatar_top - min_y;
+
+    if space_available < space_needed {
+        BubblePosition::Below
+    } else {
+        BubblePosition::Above
+    }
 }
 
 /// Get a unique key for a member (for Leptos For keying).
@@ -123,6 +228,12 @@ pub fn AvatarCanvas(
     /// Opacity for fade-out animation (0.0 to 1.0, default 1.0).
     #[prop(default = 1.0)]
     opacity: f64,
+    /// Scene width in scene coordinates (for boundary calculations).
+    #[prop(optional)]
+    scene_width: Option<Signal<f64>>,
+    /// Scene height in scene coordinates (for boundary calculations).
+    #[prop(optional)]
+    scene_height: Option<Signal<f64>>,
 ) -> impl IntoView {
     let canvas_ref = NodeRef::<leptos::html::Canvas>::new();
 
@@ -156,9 +267,31 @@ pub fn AvatarCanvas(
         // Avatar is a 3x3 grid of props, each prop is prop_size
         let avatar_size = ps * 3.0;
 
-        // Calculate canvas position from scene coordinates, adjusted for content bounds
-        let canvas_x = m.member.position_x * sx + ox - avatar_size / 2.0 - x_content_offset;
-        let canvas_y = m.member.position_y * sy + oy - avatar_size / 2.0 - y_content_offset;
+        // Get scene dimensions (use large defaults if not provided)
+        let sw = scene_width.map(|s| s.get()).unwrap_or(10000.0);
+        let sh = scene_height.map(|s| s.get()).unwrap_or(10000.0);
+
+        // Compute screen boundaries for avatar clamping
+        let boundaries = ScreenBoundaries::from_transform(sw, sh, sx, sy, ox, oy);
+
+        // Calculate raw avatar screen position
+        let avatar_screen_x = m.member.position_x * sx + ox;
+        let avatar_screen_y = m.member.position_y * sy + oy;
+
+        // Clamp avatar center so visual bounds stay within screen boundaries
+        // Use actual content extent rather than full 3x3 grid
+        let content_half_width = content_bounds.content_width(ps) / 2.0;
+        let content_half_height = content_bounds.content_height(ps) / 2.0;
+        let (clamped_x, clamped_y) = boundaries.clamp_avatar_center(
+            avatar_screen_x,
+            avatar_screen_y,
+            content_half_width,
+            content_half_height,
+        );
+
+        // Calculate canvas position from clamped screen coordinates, adjusted for content bounds
+        let canvas_x = clamped_x - avatar_size / 2.0 - x_content_offset;
+        let canvas_y = clamped_y - avatar_size / 2.0 - y_content_offset;
 
         // Fixed text dimensions (independent of prop_size/zoom)
         let text_scale = te * BASE_TEXT_SCALE;
@@ -170,12 +303,40 @@ pub fn AvatarCanvas(
         let fixed_name_height = 20.0 * text_scale;
         let fixed_text_width = 200.0 * text_scale;
 
-        // Canvas must fit both avatar AND fixed-size text
+        // Determine bubble position based on available space above avatar
+        // This must match the logic in the Effect that draws the bubble
+        let bubble_position = if bubble.is_some() {
+            // Use clamped avatar screen position for bubble calculation
+            let avatar_half_height = avatar_size / 2.0 + y_content_offset;
+
+            // Calculate bubble height using actual content (includes tail + gap)
+            let estimated_bubble_height = bubble.as_ref()
+                .map(|b| estimate_bubble_height(&b.message.content, text_scale))
+                .unwrap_or(0.0);
+
+            determine_bubble_position(
+                clamped_y,
+                avatar_half_height,
+                estimated_bubble_height,
+                0.0, // Already included in estimate_bubble_height
+                0.0, // Already included in estimate_bubble_height
+                boundaries.min_y,
+            )
+        } else {
+            BubblePosition::Above // Default when no bubble
+        };
+
+        // Canvas must fit avatar, text, AND bubble (positioned based on bubble location)
         let canvas_width = avatar_size.max(fixed_text_width);
         let canvas_height = avatar_size + fixed_bubble_height + fixed_name_height;
 
-        // Adjust position to account for extra space above avatar
-        let adjusted_y = canvas_y - fixed_bubble_height;
+        // Adjust position based on bubble position
+        // When bubble is above: offset canvas upward to make room at top
+        // When bubble is below: no upward offset, bubble goes below avatar
+        let adjusted_y = match bubble_position {
+            BubblePosition::Above => canvas_y - fixed_bubble_height,
+            BubblePosition::Below => canvas_y,
+        };
 
         format!(
             "position: absolute; \
@@ -245,6 +406,42 @@ pub fn AvatarCanvas(
             let fixed_name_height = 20.0 * text_scale;
             let fixed_text_width = 200.0 * text_scale;
 
+            // Determine bubble position early so we can position the avatar correctly
+            let y_content_offset = content_bounds.y_offset(ps);
+            let bubble_position = if bubble.is_some() {
+                let sx = scale_x.get();
+                let sy = scale_y.get();
+                let ox = offset_x.get();
+                let oy = offset_y.get();
+
+                // Get scene dimensions (use large defaults if not provided)
+                let sw = scene_width.map(|s| s.get()).unwrap_or(10000.0);
+                let sh = scene_height.map(|s| s.get()).unwrap_or(10000.0);
+
+                // Compute screen boundaries
+                let boundaries = ScreenBoundaries::from_transform(sw, sh, sx, sy, ox, oy);
+
+                // Calculate avatar's screen position
+                let avatar_screen_y = m.member.position_y * sy + oy;
+                let avatar_half_height = avatar_size / 2.0 + y_content_offset;
+
+                // Calculate bubble height using actual content (includes tail + gap)
+                let estimated_bubble_height = bubble.as_ref()
+                    .map(|b| estimate_bubble_height(&b.message.content, text_scale))
+                    .unwrap_or(0.0);
+
+                determine_bubble_position(
+                    avatar_screen_y,
+                    avatar_half_height,
+                    estimated_bubble_height,
+                    0.0, // Already included in estimate_bubble_height
+                    0.0, // Already included in estimate_bubble_height
+                    boundaries.min_y,
+                )
+            } else {
+                BubblePosition::Above
+            };
+
             let canvas_width = avatar_size.max(fixed_text_width);
             let canvas_height = avatar_size + fixed_bubble_height + fixed_name_height;
 
@@ -263,8 +460,13 @@ pub fn AvatarCanvas(
             ctx.clear_rect(0.0, 0.0, canvas_width, canvas_height);
 
             // Avatar center position within the canvas
+            // When bubble is above: avatar is below the bubble space
+            // When bubble is below: avatar is at the top, bubble space is below
             let avatar_cx = canvas_width / 2.0;
-            let avatar_cy = fixed_bubble_height + avatar_size / 2.0;
+            let avatar_cy = match bubble_position {
+                BubblePosition::Above => fixed_bubble_height + avatar_size / 2.0,
+                BubblePosition::Below => avatar_size / 2.0,
+            };
 
             // Helper to load and draw an image
             // Images are cached; when loaded, triggers a redraw via signal
@@ -393,14 +595,32 @@ pub fn AvatarCanvas(
                 if b.expires_at >= current_time {
                     let content_x_offset = content_bounds.x_offset(cell_size);
                     let content_top_adjustment = content_bounds.empty_top_rows() as f64 * cell_size;
+
+                    // Get screen boundaries for horizontal clamping
+                    let sx = scale_x.get();
+                    let sy = scale_y.get();
+                    let ox = offset_x.get();
+                    let oy = offset_y.get();
+                    let sw = scene_width.map(|s| s.get()).unwrap_or(10000.0);
+                    let sh = scene_height.map(|s| s.get()).unwrap_or(10000.0);
+                    let boundaries = ScreenBoundaries::from_transform(sw, sh, sx, sy, ox, oy);
+
+                    // Avatar top and bottom Y within the canvas
+                    let avatar_top_y = avatar_cy - avatar_size / 2.0;
+                    let avatar_bottom_y = avatar_cy + avatar_size / 2.0;
+
+                    // Use the pre-calculated bubble_position from earlier
                     draw_bubble(
                         &ctx,
                         b,
                         avatar_cx,
-                        avatar_cy - avatar_size / 2.0,
+                        avatar_top_y,
+                        avatar_bottom_y,
                         content_x_offset,
                         content_top_adjustment,
                         te,
+                        bubble_position,
+                        Some(&boundaries),
                     );
                 }
             }
@@ -434,16 +654,31 @@ fn normalize_asset_path(path: &str) -> String {
     }
 }
 
-/// Draw a speech bubble above the avatar.
+/// Draw a speech bubble relative to the avatar with boundary awareness.
+///
+/// # Arguments
+/// * `ctx` - Canvas rendering context
+/// * `bubble` - The active bubble data
+/// * `center_x` - Avatar center X in canvas coordinates
+/// * `top_y` - Avatar top edge Y in canvas coordinates
+/// * `bottom_y` - Avatar bottom edge Y in canvas coordinates
+/// * `content_x_offset` - X offset to center on content
+/// * `content_top_adjustment` - Y adjustment for empty top rows
+/// * `text_em_size` - Text size multiplier
+/// * `position` - Whether to render above or below the avatar
+/// * `boundaries` - Screen boundaries for horizontal clamping (optional)
 #[cfg(feature = "hydrate")]
 fn draw_bubble(
     ctx: &web_sys::CanvasRenderingContext2d,
     bubble: &ActiveBubble,
     center_x: f64,
     top_y: f64,
+    bottom_y: f64,
     content_x_offset: f64,
     content_top_adjustment: f64,
     text_em_size: f64,
+    position: BubblePosition,
+    boundaries: Option<&ScreenBoundaries>,
 ) {
     // Text scale independent of zoom - only affected by user's text_em_size setting
     let text_scale = text_em_size * BASE_TEXT_SCALE;
@@ -453,6 +688,7 @@ fn draw_bubble(
     let line_height = 16.0 * text_scale;
     let tail_size = 8.0 * text_scale;
     let border_radius = 8.0 * text_scale;
+    let gap = 5.0 * text_scale;
 
     let (bg_color, border_color, text_color) = emotion_bubble_colors(&bubble.message.emotion);
 
@@ -474,11 +710,41 @@ fn draw_bubble(
 
     // Center bubble horizontally on content (not grid center)
     let content_center_x = center_x + content_x_offset;
-    let bubble_x = content_center_x - bubble_width / 2.0;
 
-    // Position vertically closer to content when top rows are empty
-    let adjusted_top_y = top_y + content_top_adjustment;
-    let bubble_y = adjusted_top_y - bubble_height - tail_size - 5.0 * text_scale;
+    // Calculate initial bubble X position (centered on content)
+    let mut bubble_x = content_center_x - bubble_width / 2.0;
+
+    // Clamp bubble horizontally to stay within drawable area
+    if let Some(bounds) = boundaries {
+        let bubble_left = bubble_x;
+        let bubble_right = bubble_x + bubble_width;
+
+        if bubble_left < bounds.min_x {
+            // Shift right to stay within left edge
+            bubble_x = bounds.min_x;
+        } else if bubble_right > bounds.max_x {
+            // Shift left to stay within right edge
+            bubble_x = bounds.max_x - bubble_width;
+        }
+    }
+
+    // Calculate tail center - point toward content center but stay within bubble bounds
+    let tail_center_x = content_center_x
+        .max(bubble_x + tail_size + border_radius)
+        .min(bubble_x + bubble_width - tail_size - border_radius);
+
+    // Calculate vertical position based on bubble position
+    let bubble_y = match position {
+        BubblePosition::Above => {
+            // Position vertically closer to content when top rows are empty
+            let adjusted_top_y = top_y + content_top_adjustment;
+            adjusted_top_y - bubble_height - tail_size - gap
+        }
+        BubblePosition::Below => {
+            // Position below avatar with gap for tail
+            bottom_y + tail_size + gap
+        }
+    };
 
     // Draw bubble background
     draw_rounded_rect(ctx, bubble_x, bubble_y, bubble_width, bubble_height, border_radius);
@@ -490,9 +756,20 @@ fn draw_bubble(
 
     // Draw tail pointing to content center
     ctx.begin_path();
-    ctx.move_to(content_center_x - tail_size, bubble_y + bubble_height);
-    ctx.line_to(content_center_x, bubble_y + bubble_height + tail_size);
-    ctx.line_to(content_center_x + tail_size, bubble_y + bubble_height);
+    match position {
+        BubblePosition::Above => {
+            // Tail points DOWN toward avatar
+            ctx.move_to(tail_center_x - tail_size, bubble_y + bubble_height);
+            ctx.line_to(tail_center_x, bubble_y + bubble_height + tail_size);
+            ctx.line_to(tail_center_x + tail_size, bubble_y + bubble_height);
+        }
+        BubblePosition::Below => {
+            // Tail points UP toward avatar
+            ctx.move_to(tail_center_x - tail_size, bubble_y);
+            ctx.line_to(tail_center_x, bubble_y - tail_size);
+            ctx.line_to(tail_center_x + tail_size, bubble_y);
+        }
+    }
     ctx.close_path();
     ctx.set_fill_style_str(bg_color);
     ctx.fill();
diff --git a/crates/chattyness-user-ui/src/components/scene_viewer.rs b/crates/chattyness-user-ui/src/components/scene_viewer.rs
index 7f0d338..4be0cae 100644
--- a/crates/chattyness-user-ui/src/components/scene_viewer.rs
+++ b/crates/chattyness-user-ui/src/components/scene_viewer.rs
@@ -854,6 +854,10 @@ pub fn RealmSceneViewer(
     let offset_x_signal = Signal::derive(move || offset_x.get());
     let offset_y_signal = Signal::derive(move || offset_y.get());
 
+    // Create signals for scene dimensions to pass to AvatarCanvas for boundary awareness
+    let scene_width_signal = Signal::derive(move || scene_width_f);
+    let scene_height_signal = Signal::derive(move || scene_height_f);
+
     // Create a map of members by key for efficient lookup
     let members_by_key = Signal::derive(move || {
         use std::collections::HashMap;
@@ -942,6 +946,8 @@ pub fn RealmSceneViewer(
                                         z_index=z
                                         active_bubble=bubble_signal
                                         text_em_size=text_em_size
+                                        scene_width=scene_width_signal
+                                        scene_height=scene_height_signal
                                     />
                                 }
                             }).collect_view()
@@ -982,6 +988,8 @@ pub fn RealmSceneViewer(
                                                 active_bubble=bubble_signal
                                                 text_em_size=text_em_size
                                                 opacity=opacity
+                                                scene_width=scene_width_signal
+                                                scene_height=scene_height_signal
                                             />
                                         })
                                     } else {