A zap answered over NWC waits on far fewer round trips, and a phone with Coinos behind another app answers from its worker. "I'm on V3 … I find nwc zaps a lot more slower than usual" (398ja, 2026-11-10). Measured from the notifier's wakes and the ASP's log over four days: a closed app took about six seconds from the push to its cosign (the Lightning part after that is one and a half), an Android phone fifteen at the median, up to thirty. Where it went: every call to the ASP and the notifier was two round trips (no Access-Control-Max-Age, so Chrome re-asked the CORS preflight after five seconds; a Cloudflare response-header rule now sets 7200 on OPTIONS for ark.coinos.io, ark-staging and nwcpush), and the worker made them one after another: answered?, GetArkInfo, Handshake, claim, a save, the chain tip, then the payment, then status ("pending"), the tip again, the held status call, and status once more for the preimage it had just been handed. Now: what the mirror alone decides (invoice, network, budgets, coins, keys) comes first with no network; the claim (which now also says "already answered", coinosv3-server 3c5e9c3) goes out beside the manager's start, whose info call, handshake and tip run together (init, warmTip/_tipFresh); a send just initiated returns to its caller instead of asking at once, and awaitLnPay settles from the held call's own answer. A worker-style send on regtest: eight calls, six in sequence, where there were thirteen. The app's own answer no longer waits a second on a phone that is on screen (only one behind another app holds back for a computer).

Android freezes an app behind another one, and the worker's nudge to it sat unread until it was opened: on a phone the worker now hands a request only to a window on screen (as it already did on iOS), nudges a hidden one in case it is awake, and answers itself; the request's lock decides between them. For that the mirror is no longer written over the worker's hand: the worker stamps its writes (workerAt), the app writes under the worker's own lock (nwc-bg-work) and folds the worker's state in first (never mid-payment), carries the stamp, absorbs it when it comes back on screen (arkBgAbsorb), and refreshes the mirror as it goes behind another app.
Tests: ln-pay-double-wake (the one held call settles; a failed or mismatched answer doesn't), sw-push-quota (an Android phone's hidden window), nwc-sw-test's notifier stand-in answers /claim as the real one; tools/ark/ln-e2e-test's pay half against regtest captaind 0.8 + CLN

Co-Authored-By: Claude Fable 5.2 <[email protected]>

1 files changed, 38 insertions, 1 deletions

diff --git a/tools/ln-pay-double-wake.test.js b/tools/ln-pay-double-wake.test.js
index 18a1943..c29d625 100644
--- a/tools/ln-pay-double-wake.test.js
+++ b/tools/ln-pay-double-wake.test.js
@@ -18,7 +18,7 @@ const asp = { initiate: null, check: null, revoked: 0, checks: 0 };
 mock.module('../src/ark/lightning.js', () => ({
   ...realLn,
   initiateLightningPayment: async () => { if (asp.initiate) throw asp.initiate; },
-  checkLightningPayment: async () => { asp.checks++; if (asp.check instanceof Error) throw asp.check; return asp.check; },
+  checkLightningPayment: async (_u, _h, wait) => { asp.checks++; (asp.waits = asp.waits || []).push(!!wait); if (asp.check instanceof Error) throw asp.check; return asp.check; },
   requestLightningPayHtlcRevocation: async () => { asp.revoked++; throw new Error('revocation should not be asked for'); },
 }));
 mock.module('../src/ark/proto.js', () => ({ ...realProto, decodeVtxo: () => ({ id: 'htlc1', point: { raw: new Uint8Array(36) } }) }));
@@ -72,3 +72,40 @@ test("a send the ASP never saw (not found) is still revoked", async () => {
   await m._driveLnPay(action).catch(() => {});
   expect(asp.revoked).toBe(1);
 });
+
+// A zap's wait is made of round trips (398ja, 2026-11-10: NWC zaps "a lot more
+// slower"). A send just handed to the ASP used to ask its status at once
+// ("pending"), fetch the chain tip to go with that, hold a call until it
+// settled, then ask once more for the preimage it had just been given: four
+// round trips where the one held call does.
+test('a fresh send: initiate, then the one held call settles it', async () => {
+  Object.assign(asp, { initiate: null, check: { status: 'success', preimage: PRE }, revoked: 0, checks: 0, waits: [] });
+  const { m, action } = mgrWith('cosigned');
+  let tips = 0;
+  m.chain = { tipHeight: async () => { tips++; return 900; } };
+  await m._driveLnPay(action);
+  expect(action.step).toBe('initiated'); // handed over, nothing asked yet
+  expect(asp.checks).toBe(0);
+  expect(tips).toBe(0);
+  const a = await m.awaitLnPay(action.id, 5000);
+  expect(a.step).toBe('done');
+  expect(a.preimage).toBe(PRE);
+  expect(asp.waits).toEqual([true]); // the held call alone
+  expect(m.state.movements.filter((x) => x.type === 'ln-send' && x.status === 'complete').length).toBe(1);
+});
+
+test('a held call that comes back failed is checked the ordinary way (and revoked)', async () => {
+  Object.assign(asp, { initiate: null, check: { status: 'failed' }, revoked: 0, checks: 0, waits: [] });
+  const { m, action } = mgrWith('initiated');
+  m._revokeLnPay = async (x) => { x.step = 'failed'; };
+  const a = await m.awaitLnPay(action.id, 5000);
+  expect(asp.waits[0]).toBe(true);
+  expect(a.step).toBe('failed');
+});
+
+test('a held call with a preimage that does not match the hash settles nothing', async () => {
+  Object.assign(asp, { initiate: null, check: { status: 'success', preimage: 'cd'.repeat(32) }, revoked: 0, checks: 0, waits: [] });
+  const { m, action } = mgrWith('initiated');
+  const a = await m.awaitLnPay(action.id, 5000);
+  expect(a.step).not.toBe('done');
+});