ReactRenderingError when calling window.openai.sendFollowUpMessage() / window.openai.callTool() from inside an MCP ui:// resource widget iframe

API Bugs
,
1

Summary

When an MCP tool returns a ui:// resource (rendered as an HTML widget inside an iframe), calling window.openai.sendFollowUpMessage() or window.openai.callTool() from inside that iframe can crash the UI with a ReactRenderingError. The widget then displays “Failed to load content” with ui_boundary_error.

This appears to happen because the conversation tree is restructured after the follow-up/tool call, and a previously valid parent node reference becomes stale. Later, code that walks the tree (via isReasoningResponseMessage) fails to resolve the parent and throws.

Error / Stack Trace

Error: getNodeByIdOrMessageId - no node found by id: xxxxxxxxxx
at Cc.getNodeByIdOrMessageId
at Cc.getParent
at Object.getParentNode
at Object.isReasoningResponseMessage

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2

Same here. Even the example repositories are not working.

5

I also get the same error after the initial prompt to trigger tools for the custom MCP widget

image
image1536×829 209 KB

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6

Hey @Berkay_Ozay, appreciate you for bringing this to our attention. We’re going to dig into this and see what’s driving it. If you’ve noticed any patterns, feel free to drop them here since that can help us narrow it down faster. We’ll share an update once we learn more.

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