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CopilotKit removes browser-storage access from tool widgets

CopilotKit has changed the default isolation of interactive tool interfaces inside chats. These widgets can no longer retain the host page’s origin, cutting access to cookies and browser storage. Some network requests now carry a null origin. Link-opening checks also refuse targets outside the permitted origin. Integrations that depend on those forms of access need adapting to the changed behaviour.

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Widgets lose the host origin

CopilotKit, a framework for adding interfaces for AI agents to applications, changes the default sandbox for tool widgets in version 1.80.0. Its release notes remove allow-same-origin from that sandbox. A widget receives an opaque origin instead of retaining the origin of the host page that displays the conversation.[1]

That change cuts the widget’s access to localStorage, sessionStorage, IndexedDB and cookies. These browser mechanisms hold persistent or session-bound data. Tool interfaces built around that access therefore encounter changed behaviour when the new sandbox applies, rather than inheriting the host page’s storage permissions.[1]

Network requests carry a null origin

Cross-origin requests made by module scripts or fetch calls now carry Origin: null. Servers that decide access through the request’s origin therefore receive a different value from these widgets. The release classifies the sandbox change as breaking for affected integrations, covering both browser storage and origin-sensitive network access.[1]

Link opening has a separate boundary

The renderer also refuses link-opening requests whose targets fall outside the permitted origin. That check governs navigation initiated through the tool interface; it sits alongside the sandbox’s storage and request-origin changes. Applications using widgets that depend on host storage, origin-specific server rules or off-origin links meet distinct restrictions in the same release.[1]

References

  1. News sourceCopilotKitCopilotKit isolates tool widgets from browser storage by default↩1↩2↩3↩4
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