diff --git a/src/vs/workbench/contrib/chat/browser/agentSessions/agentSessionsModel.ts b/src/vs/workbench/contrib/chat/browser/agentSessions/agentSessionsModel.ts
index edffef5eed8fe..d91604b22324a 100644
--- a/src/vs/workbench/contrib/chat/browser/agentSessions/agentSessionsModel.ts
+++ b/src/vs/workbench/contrib/chat/browser/agentSessions/agentSessionsModel.ts
@@ -12,6 +12,7 @@ import { IMarkdownString } from '../../../../../base/common/htmlContent.js';
 import { Disposable } from '../../../../../base/common/lifecycle.js';
 import { ResourceMap } from '../../../../../base/common/map.js';
 import { MarshalledId } from '../../../../../base/common/marshallingIds.js';
+import { safeStringify } from '../../../../../base/common/objects.js';
 import { ThemeIcon } from '../../../../../base/common/themables.js';
 import { URI, UriComponents } from '../../../../../base/common/uri.js';
 import { localize } from '../../../../../nls.js';
@@ -725,7 +726,7 @@ class AgentSessionsCache {
 			metadata: session.metadata
 		} satisfies ISerializedAgentSession));
 
-		this.storageService.store(AgentSessionsCache.SESSIONS_STORAGE_KEY, JSON.stringify(serialized), StorageScope.WORKSPACE, StorageTarget.MACHINE);
+		this.storageService.store(AgentSessionsCache.SESSIONS_STORAGE_KEY, safeStringify(serialized), StorageScope.WORKSPACE, StorageTarget.MACHINE);
 	}
 
 	loadCachedSessions(): IInternalAgentSessionData[] {