From 6d9c5d95438e81c75d2fe6f2e4284b6a16e30bea Mon Sep 17 00:00:00 2001
From: Yufeng He <40085740+he-yufeng@users.noreply.github.com>
Date: Sat, 30 May 2026 04:11:01 +0800
Subject: [PATCH] fix(core): harden context error text collection

---
 .../core/src/utils/contextLengthError.test.ts | 41 ++++++++++++++++++
 packages/core/src/utils/contextLengthError.ts | 42 +++++++++++++++++--
 2 files changed, 80 insertions(+), 3 deletions(-)

diff --git a/packages/core/src/utils/contextLengthError.test.ts b/packages/core/src/utils/contextLengthError.test.ts
index 0bd7a104148..186f8d40598 100644
--- a/packages/core/src/utils/contextLengthError.test.ts
+++ b/packages/core/src/utils/contextLengthError.test.ts
@@ -116,4 +116,45 @@ describe('contextLengthError', () => {
 
     expect(info.isExceeded).toBe(false);
   });
+
+  it('skips accessor properties that throw while collecting error text', () => {
+    const error = new Error('Connection error.');
+
+    Object.defineProperty(error, 'name', {
+      enumerable: true,
+      get() {
+        throw new TypeError('Value of "this" must be of DOMException');
+      },
+    });
+    Object.defineProperty(error, 'details', {
+      enumerable: true,
+      get() {
+        throw new TypeError('Value of "this" must be of DOMException');
+      },
+    });
+
+    const info = getContextLengthExceededInfo(error);
+
+    expect(info.isExceeded).toBe(false);
+    expect(info.message).toContain('Connection error.');
+  });
+
+  it('skips throwing accessors on plain objects', () => {
+    const errorLike: Record<string, unknown> = {};
+    Object.defineProperty(errorLike, 'detail', {
+      enumerable: true,
+      get() {
+        throw new TypeError('accessor refused');
+      },
+    });
+    Object.defineProperty(errorLike, 'message', {
+      enumerable: true,
+      value: 'context_length_exceeded: too many tokens',
+    });
+
+    const info = getContextLengthExceededInfo(errorLike);
+
+    expect(info.isExceeded).toBe(true);
+    expect(info.message).toContain('context_length_exceeded');
+  });
 });
diff --git a/packages/core/src/utils/contextLengthError.ts b/packages/core/src/utils/contextLengthError.ts
index ce0d8ff68b6..5cfe2fbc4a4 100644
--- a/packages/core/src/utils/contextLengthError.ts
+++ b/packages/core/src/utils/contextLengthError.ts
@@ -103,6 +103,32 @@ function tryParseEmbeddedJson(text: string): unknown | undefined {
   }
 }
 
+function safeReadProperty(value: object, key: string): unknown {
+  try {
+    return (value as Record<string, unknown>)[key];
+  } catch {
+    return undefined;
+  }
+}
+
+function enumerableValues(value: object): unknown[] {
+  try {
+    return Object.values(value);
+  } catch {
+    try {
+      const descriptors = Object.getOwnPropertyDescriptors(value);
+      return Object.values(descriptors)
+        .filter(
+          (descriptor): descriptor is PropertyDescriptor & { value: unknown } =>
+            'value' in descriptor && descriptor.enumerable === true,
+        )
+        .map((descriptor) => descriptor.value);
+    } catch {
+      return [];
+    }
+  }
+}
+
 function collectStrings(
   value: unknown,
   seen: Set<object>,
@@ -135,11 +161,21 @@ function collectStrings(
 
   const strings: string[] = [];
   if (value instanceof Error) {
-    strings.push(value.name, value.message);
-    strings.push(...collectStrings(value.cause, seen, depth + 1));
+    const name = safeReadProperty(value, 'name');
+    const message = safeReadProperty(value, 'message');
+
+    if (typeof name === 'string') {
+      strings.push(name);
+    }
+    if (typeof message === 'string') {
+      strings.push(message);
+    }
+    strings.push(
+      ...collectStrings(safeReadProperty(value, 'cause'), seen, depth + 1),
+    );
   }
 
-  for (const [, nested] of Object.entries(value)) {
+  for (const nested of enumerableValues(value)) {
     strings.push(...collectStrings(nested, seen, depth + 1));
   }