EcobeeAuthUnknownError: "Unexpected response after login" on Auth0 `/u/custom-prompt/` during web auth flow

[parrot-tailor]

When using the username/password web authentication flow (with MFA enabled), calling refresh_tokens() can fail with:

EcobeeAuthUnknownError: Unexpected response after login (landed at https://auth.ecobee.com/u/custom-prompt/...)

Reproduction:

from pyecobee import Ecobee

config = {
    ECOBEE_USERNAME: "your@email.com",
    ECOBEE_PASSWORD: "yourpassword",
}

ecobee = Ecobee(config=config)
ecobee.refresh_tokens()   # raises EcobeeAuthUnknownError

Additional Details:

• The library successfully posts credentials via request_tokens_web().
• It then lands on an Auth0 /u/custom-prompt/ page.
• _handle_post_password_response() has no matching case for this path and raises EcobeeAuthUnknownError.
• There is currently no handling for custom-prompt paths in const.py.

This results in failures in downstream projects (e.g. Home Assistant’s ecobee integration shows a generic “unexpected error”)

Environment:

• python-ecobee-api version: 0.4.1 (master branch)
• Triggered via standalone usage and via Home Assistant 2026.7.0 ecobee integration

Related: home-assistant/core#170439

[parrot-tailor]

A bit more context: the MFA flow does work, the custom-prompt response is if you need to accept an updated Terms of Service, so users would need to login at https://auth.ecobee.com/u/login and accept the updated TOS. Once I did that I was able to successfully complete the flow in HA.