diff --git a/apps/aelis-backend/src/enhancement/llm-client.ts b/apps/aelis-backend/src/enhancement/llm-client.ts
index 06f4636..c3b68a1 100644
--- a/apps/aelis-backend/src/enhancement/llm-client.ts
+++ b/apps/aelis-backend/src/enhancement/llm-client.ts
@@ -46,7 +46,7 @@ export function createLlmClient(config: LlmClientConfig): LlmClient {
 						type: "json_schema" as const,
 						jsonSchema: {
 							name: "enhancement_result",
-							strict: true,
+							strict: false,
 							schema: enhancementResultJsonSchema,
 						},
 					},
diff --git a/apps/aelis-backend/src/enhancement/schema.test.ts b/apps/aelis-backend/src/enhancement/schema.test.ts
index 56f1cf8..4ac0c85 100644
--- a/apps/aelis-backend/src/enhancement/schema.test.ts
+++ b/apps/aelis-backend/src/enhancement/schema.test.ts
@@ -166,11 +166,12 @@ describe("schema sync", () => {
 		expect(parseEnhancementResult(JSON.stringify(bad))).toBeNull()
 
 		// JSON Schema only allows string or null for slot values
-		const slotValueTypes =
+		const slotValueSchema =
 			enhancementResultJsonSchema.properties.slotFills.additionalProperties
-				.additionalProperties.type
-		expect(slotValueTypes).toContain("string")
-		expect(slotValueTypes).toContain("null")
-		expect(slotValueTypes).not.toContain("number")
+				.additionalProperties
+		expect(slotValueSchema.anyOf).toEqual([
+			{ type: "string" },
+			{ type: "null" },
+		])
 	})
 })
diff --git a/apps/aelis-backend/src/enhancement/schema.ts b/apps/aelis-backend/src/enhancement/schema.ts
index e2c8d7f..10d5f61 100644
--- a/apps/aelis-backend/src/enhancement/schema.ts
+++ b/apps/aelis-backend/src/enhancement/schema.ts
@@ -31,7 +31,7 @@ export const enhancementResultJsonSchema = {
 			additionalProperties: {
 				type: "object",
 				additionalProperties: {
-					type: ["string", "null"],
+					anyOf: [{ type: "string" }, { type: "null" }],
 				},
 			},
 		},