The strict decode that refuses unknown keys by path moves from the huginn
binary to eureka_state::door; the CLI re-exports it and the MCP admit takes
documents as a Value (schema still Vec<PipelineDocument>) and decodes through
it, answering InvalidInput before any call. A research note with extra keys is
refused by path and nothing is stored.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>