diff --git a/specification/resources/gen-ai/definitions.yml b/specification/resources/gen-ai/definitions.yml
index dd248822..f6e80e93 100644
--- a/specification/resources/gen-ai/definitions.yml
+++ b/specification/resources/gen-ai/definitions.yml
@@ -8013,9 +8013,34 @@ apiUpdateCustomModelMetadataInputPublic:
     description:
       example: example string
       type: string
+    input_modalities:
+      description: Input modalities supported (e.g., text, image)
+      example:
+      - example string
+      items:
+        example: example string
+        type: string
+      type: array
+    license:
+      description: License under which the model is distributed
+      example: example string
+      type: string
     name:
       example: example name
       type: string
+    output_modalities:
+      description: Output modalities supported (e.g., text, image)
+      example:
+      - example string
+      items:
+        example: example string
+        type: string
+      type: array
+    parameters:
+      description: Number of parameters in the model
+      example: "12345"
+      format: uint64
+      type: string
     tags:
       $ref: '#/CustomModelTags'
     uuid:
diff --git a/specification/resources/gen-ai/examples/curl/genai_update_custom_model_metadata.yml b/specification/resources/gen-ai/examples/curl/genai_update_custom_model_metadata.yml
index 3ba635c6..7323350d 100644
--- a/specification/resources/gen-ai/examples/curl/genai_update_custom_model_metadata.yml
+++ b/specification/resources/gen-ai/examples/curl/genai_update_custom_model_metadata.yml
@@ -8,5 +8,9 @@ source: |-
       "description": "finetuned model with olympiad math data",
       "tags": {
         "tags": ["finetuned", "new"]
-      }
+      },
+      "input_modalities": ["text"],
+      "output_modalities": ["text"],
+      "parameters": "7000000000",
+      "license": "apache-2.0"
     }'