From 3c5d2734e62badbcb499a1d4bdf3ed1db581118a Mon Sep 17 00:00:00 2001
From: Yi LIU <yi@quantstamp.com>
Date: Mon, 16 Feb 2026 15:26:57 +0800
Subject: [PATCH] fix: guard error handler against non-object thrown values

The `in` operator throws a TypeError when its right-hand operand is not
an object. In the tool execution error handler, both `'message' in err`
and `'cause' in err` will crash if the caught value is a primitive
(null, string, number, undefined).

Add `typeof err === 'object'` checks before using the `in` operator to
ensure primitive thrown values are safely converted to strings.
---
 src/main.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/main.ts b/src/main.ts
index ca951c61c..348896e11 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -225,8 +225,11 @@ function registerTool(tool: ToolDefinition): void {
         return result;
       } catch (err) {
         logger(`${tool.name} error:`, err, err?.stack);
-        let errorText = err && 'message' in err ? err.message : String(err);
-        if ('cause' in err && err.cause) {
+        let errorText =
+          err && typeof err === 'object' && 'message' in err
+            ? err.message
+            : String(err);
+        if (err && typeof err === 'object' && 'cause' in err && err.cause) {
           errorText += `\nCause: ${err.cause.message}`;
         }
         return {