Extensions

Copy Markdown View Source

An extension adds negotiated behavior without changing the core protocol profile. It implements Snodo.Extension, declares exact-versioned Snodo.Extension.Method values, and is installed on the server:

use Snodo.Server,
  name: "my-server",
  version: "1.0.0",
  extensions: [MyApp.Extension]

Runtime construction rejects duplicate extension IDs, methods that collide with any core method (including unsupported and MRTR-only ones), and collisions between extensions. An installed route runs only when both peers advertise the extension and its callback accepts the negotiation. An advertised, compatible extension may also wrap core dispatch and contribute HTTP policy through generic hooks. An installed but unadvertised extension does nothing.

See examples/06_custom_extension.exs.

Tasks

snodo_tasks implements the io.modelcontextprotocol/tasks extension on those hooks. It augments tools/call, keeps tasks/get, tasks/update, and tasks/cancel outside the core catalog, and adds taskIds filters and notifications/tasks to subscriptions.

The application owns the store and runner. The package includes memory and DETS stores; snodo_tasks_postgres and snodo_tasks_sqlite add transactional stores behind an application-owned Ecto Repo. Recovery is at-least-once, so work must use its stable idempotency key for external effects.

Examples 07, 08, 09, and 17 run from extensions/tasks; example 10 from extensions/tasks_postgres with a live database; example 11 from extensions/tasks_sqlite.