diff --git a/.changeset/mighty-tigers-sing.md b/.changeset/mighty-tigers-sing.md
new file mode 100644
index 0000000..65ddc81
--- /dev/null
+++ b/.changeset/mighty-tigers-sing.md
@@ -0,0 +1,5 @@
+---
+'@crowdstrike/foundry-js': minor
+---
+
+Enforce mandatory definitionID for API Integration calls
diff --git a/src/api.ts b/src/api.ts
index 5f7bf44..1122499 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -184,7 +184,7 @@ export default class FalconApi<DATA extends LocalData = LocalData> {
     operationId,
   }: {
     operationId: string;
-    definitionId?: string;
+    definitionId: string;
   }) {
     assertConnection(this);
 
@@ -194,7 +194,7 @@ export default class FalconApi<DATA extends LocalData = LocalData> {
 
     const apiIntegration = new ApiIntegration(this, {
       operationId,
-      definitionId: definitionId ?? this.data?.app.id,
+      definitionId: definitionId,
     });
 
     this.apiIntegrations.push(apiIntegration);