address review comments

semantic_conventions/trace/instrumentation/graphql.yml

@@ -11,8 +11,19 @@ groups:
         examples: 'findBookById'
       - id: operation.type
         brief: "The type of the operation being executed."
-        type: string
-        examples: ['QUERY', 'MUTATION', 'SUBSCRIPTION']
+        type:
+          allow_custom_values: false
+          members:
+            - id: query
+              value: "query"
+              brief: "GraphQL query"
+            - id: mutation
+              value: "mutation"
+              brief: "GraphQL mutation"
+            - id: subscription
+              value: "subscription"
+              brief: "GraphQL subscription"
+        examples: ['query', 'mutation', 'subscription']
       - id: operation.body
         brief: "The GraphQL query being executed."
         type: string

specification/trace/semantic_conventions/instrumentation/graphql.md

@@ -14,8 +14,16 @@ MAY be used as span name.
 | Attribute  | Type | Description  | Examples  | Required |
 |---|---|---|---|---|
 | `graphql.operation.name` | string | The name of the operation being executed. | `findBookById` | No |
-| `graphql.operation.type` | string | The type of the operation being executed. | `QUERY`; `MUTATION`; `SUBSCRIPTION` | No |
+| `graphql.operation.type` | string | The type of the operation being executed. | `query`; `mutation`; `subscription` | No |
 | `graphql.operation.body` | string | The GraphQL query being executed. [1] | `query findBookById { bookById(id: ?) { name } }` | No |
 
 **[1]:** The value may be sanitized to exclude sensitive information.
+
+`graphql.operation.type` MUST be one of the following:
+
+| Value  | Description |
+|---|---|
+| `query` | GraphQL query |
+| `mutation` | GraphQL mutation |
+| `subscription` | GraphQL subscription |
 <!-- endsemconv -->