feat(third-party-actions): Aside is the recommended driver; gstack's visible browser stays the fallback

The readiness probe is lifted from {{ASIDE_SETUP}} at gen time (byte-identity pinned) and rule 3 points at browse/SKILL.md for how to drive; the consent question offers Aside first and gstack's own visible browser (handoff/resume for sign-in) as the fallback, as v1.72 framed it.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

test/skill-e2e-third-party-actions.test.ts

@@ -1,16 +1,20 @@
 /**
  * Consent-gate E2E for the Third-Party Web Actions contract (gate tier).
  *
- * The contract's behavior — offer the Aside drive when detected, degrade to
- * the first-party stack when absent, pitch the download exactly once on
- * macOS only, and NEVER offer a browser drive for Apple credential work —
- * is prose, so wording pins alone can't prove an agent follows it. These
- * five cases run the real contract section through `claude -p` in the
- * hermetic clean room with PATH shims controlling what "installed" means:
+ * The contract's behavior — offer the Aside drive first when detected, fall
+ * back to gstack's own visible browser (`$B` headed + handoff) / manual steps
+ * / defer when absent, pitch the download exactly once on macOS only, and
+ * NEVER offer a browser drive for Apple credential work — is prose, so
+ * wording pins alone can't prove an agent follows it. These five cases run
+ * the real contract section through `claude -p` in the hermetic clean room
+ * with PATH shims controlling what "installed" means:
  *
- *   tpa-present        → consent question offers the Aside drive
- *   tpa-absent-linux   → first-party offer, zero download pitch
- *   tpa-broken         → present-but-broken CLI behaves exactly like absent
+ *   tpa-present        → consent question offers the Aside drive (recommended)
+ *                        alongside the gstack drive
+ *   tpa-absent-linux   → gstack drive / manual / defer offer, zero download pitch
+ *   tpa-broken         → present-but-not-running CLI: "open the Aside app" ask
+ *                        or the gstack drive / manual / defer question — never
+ *                        an Aside drive offer
  *   tpa-absent-darwin  → aside.com pitch exactly once, names macOS 15+
  *   tpa-apple-ban      → ZERO drive offers for an app-specific password
  *                        (the fork shipped this exact incident once; never again)
@@ -47,7 +51,7 @@ function contractSection(): string {
 }
 
 interface ShimSpec {
-  /** aside shim behavior: 'ok' answers --version/--help, 'broken' exits 1, 'absent' = no shim. */
+  /** aside shim behavior: 'ok' answers the repl readiness probe + --version/--help, 'broken' exits 1, 'absent' = no shim. */
   aside: 'ok' | 'broken' | 'absent';
   /** What the shimmed `uname` prints (deterministic across dev/CI platforms). */
   uname: 'Darwin' | 'Linux';
@@ -61,7 +65,7 @@ function setupCase(spec: ShimSpec, extraDocs: Record<string, string> = {}) {
 
   if (spec.aside !== 'absent') {
     const body = spec.aside === 'ok'
-      ? '#!/bin/sh\ncase "$1" in\n  --version) echo "aside 1.26.810.1915"; exit 0 ;;\n  --help) echo "usage: aside [exec|repl|mcp] ..."; exit 0 ;;\n  *) echo "aside: daemon not reachable — make sure Aside Browser is running" >&2; exit 1 ;;\nesac\n'
+      ? '#!/bin/sh\ncase "$1" in\n  --version) echo "aside 1.26.810.1915"; exit 0 ;;\n  --help) echo "usage: aside [exec|repl|mcp] ..."; exit 0 ;;\n  repl) echo "ASIDE_READY /tmp/aside-shim-session"; exit 0 ;;\n  *) echo "aside: daemon not reachable — make sure Aside Browser is running" >&2; exit 1 ;;\nesac\n'
       : '#!/bin/sh\necho "aside: daemon not reachable — make sure Aside Browser is running" >&2\nexit 1\n';
     fs.writeFileSync(path.join(shimDir, 'aside'), body, { mode: 0o755 });
   }
@@ -156,7 +160,7 @@ describeIfSelected('third-party-actions consent gate', TPA_TESTS, () => {
     } finally { cleanup(); }
   }, 6 * 60_000);
 
-  // aside absent on Linux → first-party offer, ZERO download pitch.
+  // aside absent on Linux → gstack drive / manual / defer, ZERO download pitch.
   testIfSelected('tpa-absent-linux', async () => {
     const { workDir, env, cleanup } = setupCase({ aside: 'absent', uname: 'Linux' });
     try {
@@ -175,11 +179,15 @@ describeIfSelected('third-party-actions consent gate', TPA_TESTS, () => {
       // keep the contract's B/C/D lettering with A dropped (observed live).
       expect(text).toMatch(/\b[A-D]\)/);
       expect(text).toMatch(/manual/i);
+      // The gstack drive is the universal fallback — it must be on offer.
+      expect(text).toMatch(/gstack('s| own| drive)|\$B|headed|visible browser/i);
     } finally { cleanup(); }
   }, 6 * 60_000);
 
-  // aside present but broken (daemon down at probe time) → behaves exactly
-  // like absent: no Aside drive offer.
+  // aside present but not running (the repl readiness probe fails) → the
+  // contract asks the user to open the Aside app and re-probes once, THEN
+  // treats Aside as not detected (gstack drive / manual / defer). Never an
+  // Aside drive offer.
   testIfSelected('tpa-broken', async () => {
     const { workDir, env, cleanup } = setupCase({ aside: 'broken', uname: 'Linux' });
     try {
@@ -191,11 +199,15 @@ describeIfSelected('third-party-actions consent gate', TPA_TESTS, () => {
       recordE2E(evalCollector, 'tpa-broken', 'e2e-third-party-actions', result);
       expect(result.exitReason).toBe('success');
       const text = assistantText(result.transcript);
-      expect(text).not.toMatch(/in your Aside browser/i);
-      // Lettered consent question; broken-daemon renderings legitimately keep
-      // the contract's B/C/D lettering with the Aside option dropped
-      // (observed live), so accept any option letter.
-      expect(text).toMatch(/\b[A-D]\)/);
+      expect(text).not.toMatch(/in your Aside browser/i); // load-bearing negative
+      // Either outcome the contract permits in one-shot `claude -p`: the
+      // "open the Aside app" ask (agent stops at the re-probe), or the lettered
+      // gstack drive / manual / defer question (any letter — agents keep the
+      // contract's B/C/D lettering with the Aside option dropped, observed live).
+      const askedToOpen = /open the Aside app/i.test(text);
+      const letteredQuestion = /\b[A-D]\)/.test(text);
+      expect({ askedToOpen, letteredQuestion, ok: askedToOpen || letteredQuestion })
+        .toMatchObject({ ok: true });
     } finally { cleanup(); }
   }, 6 * 60_000);