Watch what your app decides

You will watch the decisions your app makes (which hosts it may call, who may do what), check them in a test, and print them while you debug. It takes about 10 minutes.

You need

• A MainSDK app with a main.yaml, run from the repository (nothing here is published to npm).
• A network.allow list with at least one host.

Steps

1. Subscribe to the network decisions. The callback runs off the request path and can't change a call.

   import { observe } from "mainsdk";
   
   export const stop = observe("mainsdk:network.decision", (e) => {
     console.log(e.data.host, e.data.decision);
   });

2. Assert on events in a test. createTestApp() records them as they happen, so no flush is needed.

   const app = createTestApp();
   await app.access.check({
     subject: { id: "u1", roles: [] },
     action: "orders.write",
     resource: { type: "orders" },
   });
   assert.equal(app.events("mainsdk:access.decision")[0]?.data.decision, "deny");

3. Print while you debug. In development, set MAINSDK_DEBUG=mainsdk:access.* and run the app. Each matching event prints one line with its channel, decision and reasons.

What you get

Every event is redacted before an observer sees it and holds no request body, prompt or secret. Read the channels reference for each payload, and observe for the calls.