diff --git a/src/lib/openapi/spec/sdk-context-schema.test.ts b/src/lib/openapi/spec/sdk-context-schema.test.ts
index 38ce31511e..79b0cf63d2 100644
--- a/src/lib/openapi/spec/sdk-context-schema.test.ts
+++ b/src/lib/openapi/spec/sdk-context-schema.test.ts
@@ -25,3 +25,33 @@ test('sdkContextSchema', () =>
                 validateSchema(sdkContextSchema.$id, data) === undefined,
         ),
     ));
+
+test('using objects as values (outside of the `properties` property) is invalid', () => {
+    const inputs = [
+        {
+            appName: 'test',
+            array: [],
+        },
+        {
+            appName: 'test',
+            object: {},
+        },
+        {
+            appName: 'test',
+            properties: {
+                array: [],
+            },
+        },
+        {
+            appName: 'test',
+            properties: {
+                object: {},
+            },
+        },
+    ];
+
+    const validationResults = inputs.map((input) =>
+        validateSchema(sdkContextSchema.$id, input),
+    );
+    expect(validationResults.every((error) => error !== undefined)).toBe(true);
+});
diff --git a/src/lib/openapi/spec/sdk-context-schema.ts b/src/lib/openapi/spec/sdk-context-schema.ts
index 61080b9023..8412333a04 100644
--- a/src/lib/openapi/spec/sdk-context-schema.ts
+++ b/src/lib/openapi/spec/sdk-context-schema.ts
@@ -5,7 +5,9 @@ export const sdkContextSchema = {
     description: 'The Unleash context as modeled in client SDKs',
     type: 'object',
     required: ['appName'],
-    additionalProperties: true,
+    additionalProperties: {
+        type: 'string',
+    },
     properties: {
         appName: {
             type: 'string',