diff --git a/openapi.yaml b/openapi.yaml
index 77d0e2318..3b602e0f6 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -2347,7 +2347,12 @@ components:
           description: Device type (cuda, mps, cpu, etc.)
         index:
           type: number
-          description: Device index
+          nullable: true
+          description: |
+            Device index within its type (e.g. CUDA ordinal for `cuda:0`,
+            `cuda:1`). `null` for devices with no index, including the CPU
+            device returned in `--cpu` mode (PyTorch's `torch.device('cpu').index`
+            is `None`).
         vram_total:
           type: number
           description: Total VRAM in bytes
@@ -2503,7 +2508,18 @@ components:
           description: Alternative search terms for finding this node
         essentials_category:
           type: string
-          description: Category override used by the essentials pack
+          nullable: true
+          description: |
+            Category override used by the essentials pack. The
+            `essentials_category` key may be present with a string value,
+            present and `null`, or absent entirely:
+
+            - V1 nodes: `essentials_category` is **omitted** when the node
+              class doesn't define an `ESSENTIALS_CATEGORY` attribute, and
+              **`null`** if the attribute is explicitly set to `None`.
+            - V3 nodes (`comfy_api.latest.io`): `essentials_category` is
+              **always present**, and **`null`** for nodes whose `Schema`
+              doesn't populate it.
 
     # -------------------------------------------------------------------
     # Models