From 4617d71ba7f6bc506f347d4fa3dad50b0ef20187 Mon Sep 17 00:00:00 2001
From: can1357 <me@can.ac>
Date: Sat, 18 Jul 2026 20:22:02 +0200
Subject: [PATCH] fix(browser): keep raw AbortSignal identity through run
 facade

Native combinators (AbortSignal.any, fetch) brand-check internal slots
that a Proxy cannot forward; return signals unwrapped from
bindBrowserRunFacade so tab.signal composes with native cancellation.
---
 packages/coding-agent/src/tools/browser/run-cancellation.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/coding-agent/src/tools/browser/run-cancellation.ts b/packages/coding-agent/src/tools/browser/run-cancellation.ts
index d2313af14..2fc638fce 100644
--- a/packages/coding-agent/src/tools/browser/run-cancellation.ts
+++ b/packages/coding-agent/src/tools/browser/run-cancellation.ts
@@ -117,6 +117,10 @@ export function bindBrowserRunFacade<T extends object>(target: T, signal: AbortS
 				return wrapped;
 			}
 			if (value && typeof value === "object") {
+				// Never proxy AbortSignals: native combinators (AbortSignal.any, fetch)
+				// brand-check internal slots that a Proxy cannot forward, and reading a
+				// signal needs no abort gating anyway.
+				if (value instanceof AbortSignal) return value;
 				const wrapped = bindBrowserRunFacade(value, signal);
 				cache.set(prop, wrapped);
 				return wrapped;