Identify the SubscriptionTopic canonical URL for the event of interest from the FHIR server's capability documentation or SubscriptionTopic resources; do not guess canonical URLs — retrieve them from the server or IG.
Build the Subscription resource with channel.type set to 'rest-hook' and channel.endpoint set to the HTTPS URL of your notification receiver; set channel.payload to the desired MIME type for the notification (verify supported payload types with the server).
Include the appropriate filters on the Subscription to scope notifications to the relevant patient or resource criteria, reducing notification volume.
POST the Subscription and handle the server's $get-ws-binding-token or handshake mechanism (for rest-hook, the server will typically POST a handshake bundle to your endpoint — respond with 200).
At your rest-hook endpoint, parse incoming notification bundles to extract resource references or full resource content depending on the configured payload type.
Implement a heartbeat check: if your endpoint does not receive expected notifications or heartbeats within the configured period, re-query the Subscription to confirm its status and reactivate if needed.
Known gotchas
rest-hook endpoints must use HTTPS; most FHIR servers will not deliver notifications to plain HTTP endpoints due to security requirements.
Channel filters are applied server-side — if the server does not support the filter parameter you specify, it may either ignore the filter (sending all notifications) or reject the Subscription entirely.
Subscription resources have an end element — if omitted or set to a past date, the subscription will expire; set end appropriately for long-running notification needs.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp