@@ -120,6 +120,35 @@ test("preserves whole-event deprecation through a referenced event envelope", ()
     assert.match(renderEventVariantClass(variants[0], "com.github.copilot.generated"), /@Deprecated/);
 });
 
+test("preserves whole-event experimental stability through a referenced event envelope", () => {
+    const schema: JSONSchema7 = {
+        definitions: {
+            SessionEvent: { anyOf: [{ $ref: "#/definitions/ExperimentalEvent" }] },
+            ExperimentalEvent: {
+                type: "object",
+                stability: "experimental",
+                properties: {
+                    type: { const: "session.experimental" },
+                    data: { $ref: "#/definitions/ExperimentalData" },
+                },
+            } as JSONSchema7,
+            ExperimentalData: { type: "object", properties: { phase: { type: "string" } } },
+        },
+    };
+    const variants = extractEventVariants(schema);
+    assert.equal(variants.length, 1);
+    assert.equal(variants[0].stability, "experimental");
+    const source = renderEventVariantClass(variants[0], "com.github.copilot.generated");
+    assert.match(
+        source,
+        /@CopilotExperimental\n(?:@[^\n]*\n)*public final class SessionExperimentalEvent\b/,
+    );
+    assert.match(
+        source,
+        /    @CopilotExperimental\n(?:    @[^\n]*\n)*    public record SessionExperimentalEventData\b/,
+    );
+});
+
 for (const referencedData of [false, true]) {
     for (const eventDeprecated of [false, true]) {
         for (const dataDeprecated of [false, true]) {
 
@@ -1545,7 +1545,8 @@ export function extractEventVariants(schema: JSONSchema7): EventVariant[] {
                 className: `${baseName}Event`,
                 dataSchema: dataSchema ?? null,
                 description: resolved.description,
-                stability: (variant as unknown as Record<string, unknown>).stability as string | undefined,
+                stability: ((resolved as unknown as Record<string, unknown>).stability
+                    ?? (variant as unknown as Record<string, unknown>).stability) as string | undefined,
                 deprecated: (resolved as unknown as Record<string, unknown>).deprecated === true,
                 dataDeprecated: dataSchema !== undefined && "deprecated" in dataSchema && dataSchema.deprecated === true,
             };
@@ -1917,7 +1918,7 @@ export function renderEventVariantClass(variant: EventVariant, packageName: stri
     }
     if (variant.stability === "experimental") {
         lines.push(` *`);
-        lines.push(` * @apiNote This method is experimental and may change in a future version.`);
+        lines.push(` * @apiNote This event type is experimental and may change in a future version.`);
     }
     lines.push(` * @since 1.0.0`);
     lines.push(` */`);
@@ -1951,6 +1952,10 @@ export function renderEventVariantClass(variant: EventVariant, packageName: stri
         if (variant.dataDeprecated) {
             lines.push(`    @Deprecated`);
         }
+        if (variant.stability === "experimental" || isSchemaExperimental(variant.dataSchema)) {
+            allImports.add("com.github.copilot.CopilotExperimental");
+            lines.push(`    @CopilotExperimental`);
+        }
         lines.push(`    @JsonIgnoreProperties(ignoreUnknown = true)`);
         lines.push(`    @JsonInclude(JsonInclude.Include.NON_NULL)`);
         if (hasUnionData) {