diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..20644a9
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,52 @@
+# TrackLab — Claude Code Guide
+
+## Project overview
+
+TrackLab is a browser-based physics video analysis tool. Users load a video, place a coordinate system, calibrate real-world distances, and auto-track objects across frames using OpenCV.
+
+## Where to work
+
+Most feature development happens in two directories:
+
+```
+src/screen-name/model/     ← application state
+src/screen-name/view/      ← all UI components
+```
+
+**Model** (`src/screen-name/model/SimModel.ts`) holds every piece of reactive state as Axon `Property` objects (playback position, duration, overlay visibility, model-view transform). If you need a new piece of shared state, add it here.
+
+**View** (`src/screen-name/view/`) contains all SceneryStack nodes. Key files:
+
+| File | Responsibility |
+|------|----------------|
+| `VideoPlayerNode.ts` | Video element, playback controls, scrubber, time/frame display |
+| `SimScreenView.ts` | Root layout, model-view transform computation |
+| `CoordinateSystemNode.ts` | Draggable/rotatable axes overlay |
+| `CalibrationToolNode.ts` | Reference distance calibration tool |
+| `AutoTrackerNode.ts` | Tracking selection box and trail rendering |
+| `ControlPanel.ts` | Left-side toggle panel |
+| `WebcamPanel.ts` | Webcam recording dialog |
+
+The other source directories are less frequently modified:
+
+- `src/tracking/` — OpenCV template-matching pipeline (touch only for tracking algorithm changes)
+- `src/i18n/` — Localization strings (English and French)
+- `src/` root files (`main.ts`, `init.ts`, `TrackLabColors.ts`, etc.) — bootstrapping and global config
+
+## Development commands
+
+```bash
+npm start          # start Vite dev server at http://localhost:5173
+npm run build      # type-check (tsc) then bundle (vite build)
+npm run check      # TypeScript type check only
+npm run lint       # Biome lint
+npm run format     # Biome format
+npm run fix        # fix lint + format issues together
+```
+
+## Architecture notes
+
+- **Reactive state**: all model values are Axon `Property` / `BooleanProperty` / `DerivedProperty`. Views observe properties and update automatically — avoid manual imperative sync.
+- **Model-view transform**: `SimScreenView` computes a `modelViewTransformProperty` from the coordinate system pose and calibration data. Use it to convert between real-world units and video-pixel coordinates.
+- **Frame rate**: the codebase assumes 30 fps (`FRAME_DURATION = 1/30` in `VideoPlayerNode.ts`). Frame stepping and the frame counter both rely on this constant.
+- **SceneryStack layout**: use `HBox` / `VBox` for rows and columns. Prefer `align: 'center'` and explicit `spacing` values. Do not set absolute pixel positions unless absolutely necessary.
diff --git a/src/screen-name/view/VideoPlayerNode.ts b/src/screen-name/view/VideoPlayerNode.ts
index c96a02e..781c762 100644
--- a/src/screen-name/view/VideoPlayerNode.ts
+++ b/src/screen-name/view/VideoPlayerNode.ts
@@ -155,6 +155,38 @@ export class VideoPlayerNode extends Node {
       }
     } );
 
+    // ── Time and frame info display ────────────────────────────────────────
+    const formatDuration = ( seconds: number ): string => {
+      if ( !Number.isFinite( seconds ) || seconds <= 0 ) return '0:00';
+      const mins = Math.floor( seconds / 60 );
+      const secs = Math.floor( seconds % 60 );
+      return `${ mins }:${ String( secs ).padStart( 2, '0' ) }`;
+    };
+
+    const totalTimeTextProperty = new DerivedProperty(
+      [ model.durationProperty ],
+      ( duration: number ) => formatDuration( duration )
+    );
+
+    const frameCountTextProperty = new DerivedProperty(
+      [ model.currentTimeProperty, model.durationProperty ],
+      ( time: number, duration: number ) => {
+        if ( duration <= 0 ) return '0/0';
+        const current = Math.round( time / FRAME_DURATION );
+        const total = Math.round( duration / FRAME_DURATION );
+        return `${ current }/${ total }`;
+      }
+    );
+
+    const totalTimeLabel = new Text( totalTimeTextProperty, { font: LABEL_FONT } );
+    const frameCountLabel = new Text( frameCountTextProperty, { font: LABEL_FONT } );
+
+    const infoDisplay = new VBox( {
+      children: [ totalTimeLabel, frameCountLabel ],
+      spacing: 2,
+      align: 'left',
+    } );
+
     // ── Video source ComboBox ─────────────────────────────────────────────
     const selectedVideoProperty = new Property<string | null>( null );
 
@@ -219,7 +251,7 @@ export class VideoPlayerNode extends Node {
     } );
 
     const controlsRow = new HBox( {
-      children: [ timeControlNode, scrubber ],
+      children: [ infoDisplay, timeControlNode, scrubber ],
       spacing: 16,
       align: 'center',
     } );