try inline openapi spec

apps/api/cloudformation.yml

@@ -12,7 +12,31 @@ Resources:
       ProtocolType: HTTP
       Target: !GetAtt Lambda.Arn
       CredentialsArn: !GetAtt ApiRole.Arn
-      BodyS3Location: openapi.yml
+      Body:
+        openapi: 3.1.0
+        info:
+          title: Sample API
+          description: Optional multiline or single-line description in [CommonMark](http://commonmark.org/help/) or HTML.
+          version: 0.1.9
+        servers:
+          - url: http://api.example.com/v1
+            description: Optional server description, e.g. Main (production) server
+          - url: http://staging-api.example.com
+            description: Optional server description, e.g. Internal staging server for testing
+        paths:
+          /users:
+            get:
+              summary: Returns a list of users.
+              description: Optional extended description in CommonMark or HTML.
+              responses:
+                '200': # status code
+                  description: A JSON array of user names
+                  content:
+                    application/json:
+                      schema:
+                        type: array
+                        items:
+                          type: string
 
   ApiOverrides:
     Type: AWS::ApiGatewayV2::ApiGatewayManagedOverrides