Hello!

In the CDex Task Attachment Request Profile:

• Task.identifier:tracking-id.value is Must Support
• Task.identifier:tracking-id.system is not Must Support, but should be

Since a provider system could expect multiple Tasks submitted from multiple payer systems, there exists the potential for collisions in tracking IDs.

Please specify Task.identifier:tracking-id.system as Must Support.

For this change to be meaningful, we need a complementary change.

In the Submit Attachment Operation:

• TrackingId input parameter type is string, but should be Identifier

Additional benefits:

• Intuitively, this will be easier for implementers to understand since TrackingId ultimately corresponds to Task.identifier.
• The tracking ID's identifier.system can be used to distinguish between solicited and unsolicited invocations of $submit-attachment, which likely require somewhat different implementation details around validation and processing.
• Allows support of multiple discrete systems for tracking IDs in payer systems, which will be respected by provider systems.
  • e.g. discrete systems per LOB behind a gateway

I tried to identify all of the relevant artifacts and pages. Unfortunately, I likely missed some because there are a lot of examples that illustrate Tasks and $submit-attachment requests. Should the above changes take effect, please apply them throughout the IG as appropriate.

Thanks!