From 040eab93199bb9136233f014f5d0d1f376b404d4 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Thu, 12 Feb 2026 13:31:34 +0000
Subject: [PATCH] fix(message-transport): only ignore messages that lack
 jsonrpc: "2.0"
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Tighten the parse-failure handler: silently ignore postMessage frames
where event.data?.jsonrpc !== "2.0" (i.e. not JSON-RPC at all — null,
undefined, a primitive, or an object from the host environment that
doesn't carry the jsonrpc field). Messages that do carry jsonrpc: "2.0"
but are otherwise malformed still surface via onerror so genuine protocol
errors aren't swallowed.

https://claude.ai/code/session_01DaJpUtSJf4hA7tnu3nJz8s
---
 src/message-transport.ts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/message-transport.ts b/src/message-transport.ts
index c49aa77c6..dded70469 100644
--- a/src/message-transport.ts
+++ b/src/message-transport.ts
@@ -82,7 +82,17 @@ export class PostMessageTransport implements Transport {
       if (parsed.success) {
         console.debug("Parsed message", parsed.data);
         this.onmessage?.(parsed.data);
+      } else if (event.data?.jsonrpc !== "2.0") {
+        // Not a JSON-RPC message at all (e.g. internal frames injected by
+        // the host environment). Ignore silently so the transport stays alive.
+        console.debug(
+          "Ignoring non-JSON-RPC message",
+          parsed.error.message,
+          event,
+        );
       } else {
+        // Has jsonrpc: "2.0" but is otherwise malformed — surface as a real
+        // protocol error.
         console.error("Failed to parse message", parsed.error.message, event);
         this.onerror?.(
           new Error(