x-api-v2-402-credits-depleted-is-not-auth-failure
X API v2 returns HTTP 402 CreditsDepleted when account credits are exhausted even with a fully valid Bearer Token. This is NOT an authentication failure (which would return 401 or 403). If all calls return 402, the credentials are working and credits must be purchased from the X Developer Portal dashboard — purchase is separate from API key creation.