diff --git a/src/types/ARCHITECTURE.md b/src/types/ARCHITECTURE.md
index 1522d8aefb9..06d6064a0ee 100644
--- a/src/types/ARCHITECTURE.md
+++ b/src/types/ARCHITECTURE.md
@@ -51,7 +51,9 @@ The split:
       FontArray, ColorBar, HoverLabel, Domain, Pattern, TickFormatStops,
       LegendGroupTitle).
     - **Per-trace data interfaces** for all trace types (BarData, ScatterData,
-      IndicatorData, etc.).
+      IndicatorData, etc.), plus the **`Data` discriminated union** over all
+      of them (`Partial<BarData> | Partial<ScatterData> | …`) — narrowed via
+      the `type` field.
     - **Layout component interfaces** (LayoutAxis, Legend, Scene,
       Annotation, Shape, Slider, UpdateMenu, etc.) and the Layout
       interface itself.
@@ -85,7 +87,7 @@ This split is reflected in the types:
 | User-facing | Internal | Where defined |
 |---|---|---|
 | `Layout` | `FullLayout` | `Layout` in `generated/schema.d.ts`; `FullLayout` in `core/layout.internal.d.ts` |
-| `Data` (union over `type`) | `FullData` | `Data` in `core/data.d.ts` (union of schema `*Data` interfaces); `FullData = Data & FullDataInternals` in `core/data.internal.d.ts` |
+| `Data` (union over `type`) | `FullData` | `Data` in `generated/schema.d.ts` (union of schema `*Data` interfaces); `FullData = Data & FullDataInternals` in `core/data.internal.d.ts` |
 | (n/a) | `GraphDiv` (the `gd` param) | `core/graph-div.internal.d.ts` — DOM element with `_fullLayout`, `_fullData`, `calcdata`, etc. |
 
 `FullData` is the discriminated union of schema trace types intersected with
@@ -106,7 +108,6 @@ src/types/
 ├── core/                         # hand-written types for the core API
 │   ├── api.d.ts                  # public API function signatures (newPlot, etc.)
 │   ├── config.d.ts               # Config, ToImgopts (Edits re-exported from generated)
-│   ├── data.d.ts                 # Data union (over all schema `*Data` interfaces)
 │   ├── data.internal.d.ts        # CalcData, FullData
 │   ├── events.d.ts               # PlotMouseEvent, PlotlyHTMLElement, etc.
 │   ├── graph-div.internal.d.ts   # GraphDiv, GraphContext
@@ -173,6 +174,8 @@ src/types/generated/schema.d.ts
     │ // Trace interfaces
     │ export interface ScatterData { marker?: _internal.Marker; ... }
     │ export interface BarData { ... }
+    │ // Discriminated union over all traces
+    │ export type Data = Partial<BarData> | Partial<ScatterData> | ...;
     │ // Layout
     │ export interface LayoutAxis { autorangeoptions?: _internal.AutoRangeOptions; ... }
     │ export interface Layout { ... }
diff --git a/src/types/GENERATOR.md b/src/types/GENERATOR.md
index 018d11020b5..d5b2f188242 100644
--- a/src/types/GENERATOR.md
+++ b/src/types/GENERATOR.md
@@ -8,6 +8,7 @@ types into `src/types/generated/schema.d.ts`:
   TransitionEasing, TraceType — plus a deprecated `PlotType` alias)
 - Shared sub-interfaces (Font, ColorBar, HoverLabel, etc.)
 - Data interfaces for each trace type (BarData, ScatterData, IndicatorData, etc.)
+  and the `Data` discriminated union over all of them
 - Layout component interfaces (LayoutAxis, Legend, Scene, Annotation, etc.)
   and the Layout interface itself
 - Animation / frame / edits interfaces (AnimationOpts, Frame, Edits)
@@ -90,7 +91,11 @@ so the automatic extractor skips them, but they need to be named for
 ### Phase 3: Trace interfaces
 
 Each trace gets an interface (`ScatterData`, `BarData`, etc.) whose
-properties reference shared types where fingerprints match.
+properties reference shared types where fingerprints match. After all
+trace interfaces are emitted, the generator also emits the discriminated
+union `Data = Partial<BarData> | Partial<BarpolarData> | …` covering every
+trace — narrowed via the `type` field. Adding or removing a trace in the
+schema flows through automatically.
 
 ### Phase 4: Layout types
 
@@ -191,6 +196,7 @@ src/types/generated/schema.d.ts
 │                                                        AutoRangeOptions,
 │                                                        Lighting, ErrorY)
 ├── Trace interfaces (ScatterData, BarData, ... — 49 traces)
+├── Data union (`Partial<*Data>` over every trace, discriminated by `type`)
 ├── Layout component interfaces (LayoutAxis, Legend, Scene, Annotation, etc.)
 ├── Layout interface
 └── Animation / frames / config (AnimationOpts, Frame, Edits, ConfigBase)
diff --git a/src/types/README.md b/src/types/README.md
index 0c6a3293ba9..b11bd508fcb 100644
--- a/src/types/README.md
+++ b/src/types/README.md
@@ -48,6 +48,7 @@ The following are **auto-generated from `plot-schema.json`** by
 - Common enum aliases (Calendar, Dash, AxisType, PatternShape, XRef, YRef,
   TransitionEasing, TraceType — and a deprecated `PlotType` alias)
 - Data interfaces for each trace type (BarData, ScatterData, IndicatorData, etc.)
+  and the `Data` discriminated union over all of them
 - Layout component interfaces (LayoutAxis, Legend, Scene, Annotation,
   Shape, Slider, UpdateMenu, etc.) and the Layout interface itself
 - Shared sub-interfaces (Font, ColorBar, HoverLabel, LegendGroupTitle, etc.)
diff --git a/src/types/core/api.d.ts b/src/types/core/api.d.ts
index 32f041fe658..aa2f4bf38b0 100644
--- a/src/types/core/api.d.ts
+++ b/src/types/core/api.d.ts
@@ -2,9 +2,8 @@
  * Public API function types for Plotly.js
  */
 
-import type { AnimationOpts, Frame, Layout } from '../generated/schema';
+import type { AnimationOpts, Data, Frame, Layout } from '../generated/schema';
 import type { Config, DownloadImgopts, ToImgopts } from './config';
-import type { Data } from './data';
 import type { PlotlyHTMLElement } from './events';
 import type { Icon, Template } from './layout';
 
diff --git a/src/types/core/data.d.ts b/src/types/core/data.d.ts
deleted file mode 100644
index 8d393a2e74c..00000000000
--- a/src/types/core/data.d.ts
+++ /dev/null
@@ -1,124 +0,0 @@
-/**
- * Data/Trace types
- *
- * The `Data` union covers every trace type from the schema. Use the trace's
- * `type` field as the discriminator to narrow to a specific trace shape:
- *
- *     if (trace.type === 'bar') { trace.marker?.cornerradius }
- *     if (trace.type === 'pie') { trace.marker?.colors }
- *
- * Per-trace interfaces (BarData, PieData, IndicatorData, etc.) are generated
- * directly from the schema and re-exported from `generated/schema`.
- */
-
-import type {
-    BarData,
-    BarpolarData,
-    BoxData,
-    CandlestickData,
-    CarpetData,
-    ChoroplethData,
-    ChoroplethmapboxData,
-    ChoroplethmapData,
-    ConeData,
-    ContourcarpetData,
-    ContourData,
-    DensitymapboxData,
-    DensitymapData,
-    FunnelareaData,
-    FunnelData,
-    HeatmapData,
-    Histogram2dcontourData,
-    Histogram2dData,
-    HistogramData,
-    IcicleData,
-    ImageData,
-    IndicatorData,
-    IsosurfaceData,
-    Mesh3dData,
-    OhlcData,
-    ParcatsData,
-    ParcoordsData,
-    PieData,
-    PlotType,
-    SankeyData,
-    Scatter3dData,
-    ScattercarpetData,
-    ScatterData,
-    ScattergeoData,
-    ScatterglData,
-    ScattermapboxData,
-    ScattermapData,
-    ScatterpolarData,
-    ScatterpolarglData,
-    ScattersmithData,
-    ScatterternaryData,
-    SplomData,
-    StreamtubeData,
-    SunburstData,
-    SurfaceData,
-    TableData,
-    TraceType,
-    TreemapData,
-    ViolinData,
-    VolumeData,
-    WaterfallData
-} from '../generated/schema';
-
-export type { PlotType, TraceType };
-
-/**
- * Union of every trace shape. All fields are optional via `Partial<…>` —
- * narrow with the `type` discriminator before accessing trace-specific
- * attributes.
- */
-export type Data =
-    | Partial<BarData>
-    | Partial<BarpolarData>
-    | Partial<BoxData>
-    | Partial<CandlestickData>
-    | Partial<CarpetData>
-    | Partial<ChoroplethData>
-    | Partial<ChoroplethmapboxData>
-    | Partial<ChoroplethmapData>
-    | Partial<ConeData>
-    | Partial<ContourcarpetData>
-    | Partial<ContourData>
-    | Partial<DensitymapboxData>
-    | Partial<DensitymapData>
-    | Partial<FunnelareaData>
-    | Partial<FunnelData>
-    | Partial<HeatmapData>
-    | Partial<Histogram2dcontourData>
-    | Partial<Histogram2dData>
-    | Partial<HistogramData>
-    | Partial<IcicleData>
-    | Partial<ImageData>
-    | Partial<IndicatorData>
-    | Partial<IsosurfaceData>
-    | Partial<Mesh3dData>
-    | Partial<OhlcData>
-    | Partial<ParcatsData>
-    | Partial<ParcoordsData>
-    | Partial<PieData>
-    | Partial<SankeyData>
-    | Partial<Scatter3dData>
-    | Partial<ScattercarpetData>
-    | Partial<ScatterData>
-    | Partial<ScattergeoData>
-    | Partial<ScatterglData>
-    | Partial<ScattermapboxData>
-    | Partial<ScattermapData>
-    | Partial<ScatterpolarData>
-    | Partial<ScatterpolarglData>
-    | Partial<ScattersmithData>
-    | Partial<ScatterternaryData>
-    | Partial<SplomData>
-    | Partial<StreamtubeData>
-    | Partial<SunburstData>
-    | Partial<SurfaceData>
-    | Partial<TableData>
-    | Partial<TreemapData>
-    | Partial<ViolinData>
-    | Partial<VolumeData>
-    | Partial<WaterfallData>;
diff --git a/src/types/core/events.d.ts b/src/types/core/events.d.ts
index c4b14d9eebf..9355d47f2e5 100644
--- a/src/types/core/events.d.ts
+++ b/src/types/core/events.d.ts
@@ -8,6 +8,7 @@
 import type {
     AnimationFrameOpts,
     Annotation,
+    Data,
     Frame,
     Layout,
     LayoutAxis,
@@ -16,7 +17,6 @@ import type {
 } from '../generated/schema';
 import type { Datum } from '../lib/common';
 import type { Config } from './config';
-import type { Data } from './data';
 
 // ---------------------------------------------------------------------------
 // Point / datum types in events
diff --git a/src/types/core/graph-div.internal.d.ts b/src/types/core/graph-div.internal.d.ts
index a87362a38cb..4c621c8bad7 100644
--- a/src/types/core/graph-div.internal.d.ts
+++ b/src/types/core/graph-div.internal.d.ts
@@ -6,9 +6,8 @@
  * Commonly referred to as `gd` in the codebase.
  */
 
-import type { Layout } from '../generated/schema';
+import type { Data, Layout } from '../generated/schema';
 import type { Config } from './config';
-import type { Data } from './data';
 import type { CalcData, FullData } from './data.internal';
 import type { FullLayout } from './layout.internal';
 
diff --git a/src/types/core/layout.d.ts b/src/types/core/layout.d.ts
index f7f01c76096..bc25d3354ae 100644
--- a/src/types/core/layout.d.ts
+++ b/src/types/core/layout.d.ts
@@ -8,8 +8,7 @@
  * literal utilities, and deprecated aliases.
  */
 
-import type { Layout } from '../generated/schema';
-import type { Data, TraceType } from './data';
+import type { Data, Layout, TraceType } from '../generated/schema';
 import type { PlotlyHTMLElement } from './events';
 
 // ---------------------------------------------------------------------------
diff --git a/src/types/generated/schema.d.ts b/src/types/generated/schema.d.ts
index f4ac6ebdae6..4e44269f5e6 100644
--- a/src/types/generated/schema.d.ts
+++ b/src/types/generated/schema.d.ts
@@ -12091,6 +12091,65 @@ export interface WaterfallData {
     zorder?: number;
 }
 
+/**
+ * Union of every trace shape. All fields are optional via `Partial<…>` —
+ * narrow with the `type` discriminator before accessing trace-specific
+ * attributes:
+ *
+ *     if (trace.type === 'bar') { trace.marker?.cornerradius }
+ *     if (trace.type === 'pie') { trace.marker?.colors }
+ */
+export type Data =
+    | Partial<BarData>
+    | Partial<BarpolarData>
+    | Partial<BoxData>
+    | Partial<CandlestickData>
+    | Partial<CarpetData>
+    | Partial<ChoroplethData>
+    | Partial<ChoroplethmapData>
+    | Partial<ChoroplethmapboxData>
+    | Partial<ConeData>
+    | Partial<ContourData>
+    | Partial<ContourcarpetData>
+    | Partial<DensitymapData>
+    | Partial<DensitymapboxData>
+    | Partial<FunnelData>
+    | Partial<FunnelareaData>
+    | Partial<HeatmapData>
+    | Partial<HistogramData>
+    | Partial<Histogram2dData>
+    | Partial<Histogram2dcontourData>
+    | Partial<IcicleData>
+    | Partial<ImageData>
+    | Partial<IndicatorData>
+    | Partial<IsosurfaceData>
+    | Partial<Mesh3dData>
+    | Partial<OhlcData>
+    | Partial<ParcatsData>
+    | Partial<ParcoordsData>
+    | Partial<PieData>
+    | Partial<SankeyData>
+    | Partial<ScatterData>
+    | Partial<Scatter3dData>
+    | Partial<ScattercarpetData>
+    | Partial<ScattergeoData>
+    | Partial<ScatterglData>
+    | Partial<ScattermapData>
+    | Partial<ScattermapboxData>
+    | Partial<ScatterpolarData>
+    | Partial<ScatterpolarglData>
+    | Partial<ScattersmithData>
+    | Partial<ScatterternaryData>
+    | Partial<SplomData>
+    | Partial<StreamtubeData>
+    | Partial<SunburstData>
+    | Partial<SurfaceData>
+    | Partial<TableData>
+    | Partial<TreemapData>
+    | Partial<ViolinData>
+    | Partial<VolumeData>
+    | Partial<WaterfallData>;
+
 // ---------------------------------------------------------------------------
 // Layout component interfaces
 // ---------------------------------------------------------------------------
diff --git a/src/types/index.d.ts b/src/types/index.d.ts
index 8233cd051b7..258c0897fa3 100644
--- a/src/types/index.d.ts
+++ b/src/types/index.d.ts
@@ -11,7 +11,6 @@ export * from './lib/common';
 // Core types (public)
 export * from './core/api';
 export * from './core/config';
-export * from './core/data';
 export * from './core/events';
 export * from './core/layout';
 
diff --git a/tasks/generate_schema_types.mjs b/tasks/generate_schema_types.mjs
index 87fa258d3a2..e43a05b8e62 100644
--- a/tasks/generate_schema_types.mjs
+++ b/tasks/generate_schema_types.mjs
@@ -1156,6 +1156,25 @@ export function generateSchemaTypes(schema, outputPath) {
         chunks.push('');
     }
 
+    // Discriminated union of every trace shape. All fields are optional via
+    // `Partial<…>` — narrow with the `type` discriminator before accessing
+    // trace-specific attributes.
+    chunks.push('/**');
+    chunks.push(' * Union of every trace shape. All fields are optional via `Partial<…>` —');
+    chunks.push(' * narrow with the `type` discriminator before accessing trace-specific');
+    chunks.push(' * attributes:');
+    chunks.push(' *');
+    chunks.push(' *     if (trace.type === \'bar\') { trace.marker?.cornerradius }');
+    chunks.push(' *     if (trace.type === \'pie\') { trace.marker?.colors }');
+    chunks.push(' */');
+    chunks.push('export type Data =');
+    traceNames.forEach((traceName, i) => {
+        const interfaceName = traceNameToInterfaceName(traceName);
+        const sep = i === traceNames.length - 1 ? ';' : '';
+        chunks.push(`    | Partial<${interfaceName}>${sep}`);
+    });
+    chunks.push('');
+
     // Emit layout-specific interfaces (subplots + array items)
     chunks.push('// ---------------------------------------------------------------------------');
     chunks.push('// Layout component interfaces');
@@ -1263,6 +1282,7 @@ export function generateSchemaTypes(schema, outputPath) {
         if (!INTERNAL_INTERFACES.has(name)) exportedNames.add(name);
     }
     for (const traceName of traceNames) exportedNames.add(traceNameToInterfaceName(traceName));
+    exportedNames.add('Data');
     for (const name of subplotGroups.keys()) exportedNames.add(name);
     for (const name of arrayItems.keys()) exportedNames.add(name);
     exportedNames.add('Layout');