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/E210.md.
mfeflow

    MFEFLOW_E210

    Registry namespace is not configured.

    Fix

    Add it with mfeflow registry add @someone https://example.com/{name}.json (or under "registries" in mfeflow.json).