I’m running into a widget-loading issue with our MCP server (Sometrend)
in Codex Desktop. The tool calls succeed, but every widget fails to load.
The same server, on the same endpoint, works correctly on chatgpt.com.

Note: I’m not the developer on this server, so some low-level details are
marked as unknown below. Happy to get them if you tell me what to ask for.

Summary

  • Tool calls succeed and return valid data (code: 200)
  • The follow-up resources/read for the widget resource fails with
    -32603: Internal error
  • This happens for every tool in our server, not just one
  • Requesting the resource URI directly through the existing codex_apps
    connection fails the same way, with no tool call involved
  • The same server and endpoint work fine on chatgpt.com
  • Switching OpenAI accounts does not change anything

Environment

  • Host: Codex Desktop for macOS
  • Codex version: 26.727.51351 (released Aug 1, 2026)
  • MCP server: Sometrend (remote, same endpoint for both clients)
  • Working client for comparison: chatgpt.com
  • First observed: August 3, 2026
  • Still reproducible: August 5, 2026
  • Timezone: Asia/Seoul (UTC+9)

I first saw this two days after this build was released. We didn’t change
anything on our server around that time, though I haven’t verified whether
the previous build worked, so I can’t confirm a connection.

Exact error

MCP 앱을 불러오지 못했습니다:
resources/read failed for codex_apps
(ui://widget/social-app-GetKeywordAssociation.html):
Mcp error: -32603: Internal error

(Failed to load the MCP app: resources/read failed for codex_apps
(ui://widget/social-app-GetKeywordAssociation.html):
Mcp error: -32603: Internal error)

The prompt used was 비타민 연관어 뽑아줘 (“Extract related keywords for
vitamin”), but the keyword is not relevant. Other tools in the same server
produce the identical error with their own widget URIs.

Reproduction steps

  1. Open Codex Desktop on macOS
  2. Enable the Sometrend MCP server
  3. Start a new conversation
  4. Run any request that triggers a tool with a widget
  5. The tool returns data successfully
  6. The widget fails with resources/read -32603
  7. Run the same request on chatgpt.com
  8. The widget renders correctly

Already tried

  • Fully quit Codex Desktop (Cmd+Q) and restarted
  • Disconnected and reconnected the server
  • New conversation
  • Multiple OpenAI accounts, all fail on Desktop
  • Confirmed the server health endpoint returns ok
  • Confirmed the data tools themselves keep working

Questions

  1. Is this a known issue with widget resource loading in Codex Desktop?
  2. Does Codex Desktop resolve widget resources differently from
    chatgpt.com, for example through a separate cache or a separate
    registration of the resource list?
  3. Is there any way to see Codex Desktop’s own logs for the
    resources/read request, so I can tell whether the request reaches
    our server at all?

I can share timestamps, screenshots, and diagnostic logs privately through
a support ticket. I won’t post account identifiers, tokens, cookies, or
HAR files publicly.

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