generate_figma_design returns ChatGPT fallback message instead of capture flow in Codex

What version of the Codex App are you using (From “About Codex” dialog)?

26.602.40724

What subscription do you have?

Business

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

Summary

The generate_figma_design tool is not starting the normal capture flow in Codex.
Instead of returning a captureId and capture endpoint for the browser-based HTML-to-Figma workflow, it returns the message:

This tool works best on Codex, try use_figma instead in ChatGPT.
This blocks the established workflow of:

hosting a local HTML mock,
opening it in Chrome,
capturing it into Figma via the MCP capture script,
and then moving the generated frame into the target Figma page.
Expected Behavior

When calling generate_figma_design from Codex with a valid Figma fileKey, the tool should return the normal capture bootstrap payload, including a captureId and the corresponding capture endpoint, so the local browser capture flow can proceed.

Actual Behavior

The tool returns this fallback response instead:

This tool works best on Codex, try use_figma instead in ChatGPT.

What steps can reproduce the bug?

Steps to Reproduce

Authenticate Figma MCP successfully.
Confirm general Figma access works, for example with whoami.
Call generate_figma_design with a valid existing design file key.
Observe that the tool returns the ChatGPT fallback message instead of capture metadata.
Example Call

{
"fileKey": "YvHcp2gWamYXdxYbZykqKR123"
}
Also reproduced with:

{
"outputMode": "existingFile",
"fileKey": "YvHcp2gWamYXdxYbZykqKR123"
}
Observed Result

This tool works best on Codex, try use_figma instead in ChatGPT.
Environment

Client: Codex desktop app
Date observed: June 8, 2026
Figma MCP authentication: successful
whoami: working correctly
Target workflow: browser-based HTML mock capture into an existing Figma design file
Impact

This blocks a pixel-perfect capture-first workflow that depends on real browser rendering and Figma import.
Fallbacks such as screenshots or manual reconstruction are not acceptable replacements in this case because they reduce fidelity and break the established design workflow.

Notes

Regular Figma MCP access appears healthy.
The problem seems isolated to generate_figma_design.
This looks like the tool is incorrectly returning a ChatGPT fallback branch while being called from Codex.

What is the expected behavior?

_No response_

Additional information

_No response_