8.21Field-Level Security

Even if Mule can access:

Account

it may not be allowed to access:

Account.Sensitive_Field__c

Salesforce security can apply at:

object level
field level
record level

So this query:

SELECT Id, Secret_Field__c
FROM Account

may fail or behave differently depending on access.

Again:

schema exists

doesn't mean:

integration identity can access it