CommonHealth uses International Patient Summary Guidelines to compile clinical information from USCDI data the patient has retrieved directly from their healthcare providers.
The IPS document FHIR bundle is compiled per the HL7 FHIR International Patient Summary Implementation Guide.

In CommonHealth, records are curated by the patient from various providers and may not be exhaustive or fully up to date. CommonHealth specifies the following elements of Composition to reflect that:
In a future release, we intend to include complete Provenance details wherever possible.
CommonHealth uses the SMART Health Link (SHLink) protocol protocol to support structured sharing of the IPS.
Once the FHIR bundle is created, the user provides a passcode, chooses a lifespan for the SHLink (up to 72 hours, presently), and the data is submitted to a stateless cloud service that generates the SHLink.
The file type for the payload is defined as `application/fhir+json`. Because the clinical data originates at other organizations and is not entirely verifiable by CommonHealth at the time of composition, we are not signing the bundle and generating a SMART Health Card.
When constructing the SHLink payload:
CommonHealth SHLinks are always always prefixed with the viewer URL for the SMART Health Card and Links Reader application, “https://viewer.commonhealth.org/#” so that anyone receiving the SHLink is able to display the IPS in human readable format. The reader application is open source.