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Codex
Codex can fail before its editor panel opens, when a prompt is submitted, or halfway through a task. These guides start with the client and moment where the error appeared.
Selected model is at capacityCodex says the selected model cannot take the request.Codex · CapacityStream disconnected before completionThe connection to an in-progress Codex task ends early.Codex · TaskCould not start its user interfaceThe Codex editor panel fails to load.Codex · ExtensionCan’t find variable: DisposableStackA reported message-submission error in Safari-based Codex contexts.Codex · InterfaceFrequently Asked Questions
Why is Codex at capacity with usage left?
One public report describes the notice in Codex Desktop, Web, and CLI while the reporter’s account still showed remaining usage. Changing models and starting new sessions did not reliably help that person. Your usage display is still worth checking, but it cannot by itself explain this capacity notice. See the capacity guide before repeatedly resending a task.
What if a task disconnects mid-run?
Look at the last visible action and the files Codex may have touched. A disconnected response can leave some work on disk even when the chat never receives a completion message. Save what is useful, then ask for a small continuation or retry only the unfinished part. The stream disconnect guide explains what to record if it happens again.
Does it matter which Codex client shows the error?
Yes. “Could not start its user interface” has been reported in the VS Code extension, while DisposableStack reports concern Safari-based web contexts. A stream disconnect happens later, during a running task. Record whether you are in Codex Web, the desktop app, CLI, or the editor extension before following a workaround. Start with the DisposableStack guide if that is the wording you saw.