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

API Bugs
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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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