For AI agents: the complete documentation index is available at https://mfeflow.github.io/mfeflow/llms.txt, the full documentation bundle is available at https://mfeflow.github.io/mfeflow/llms-full.txt, and this page is available as Markdown at https://mfeflow.github.io/mfeflow/errors/E406.md.
mfeflow

    MFEFLOW_E406

    The registry changed a feature since you added it.

    Fix

    Nothing was written. Look at what changed; if you accept the new content, run the command again with --accept-changed-content.