[FEATURE] Phone number duplication is checked too late during OTP verification

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When creating a Claude Code account, during the phone number OTP verification step, the user is required to enter their phone number and then input the OTP. If the phone number has already been registered with a different email address, the system only shows an error after the OTP is entered, stating that the phone number is already associated with another account.

This results in a poor user experience, as users must wait for and enter an OTP unnecessarily. The check for whether a phone number already exists should be performed at the phone number input step, not at the OTP verification step.

Proposed Solution

Phone number duplication should be validated at the phone number input step, rather than during the OTP verification step.

Alternative Solutions

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Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

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Additional Context

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