# The lesson, stated plainly

> Source: <https://dev.to/neonmem_dev/the-lesson-stated-plainly-50ae>
> Published: 2026-06-16 07:23:03+00:00

If you persist embeddings, you must persist the embedder.A vector index is

only meaningful next to the exact model that produced it.

It's an easy mistake because everything *looks* fine — the vectors are right

there on disk, the search runs, no error is thrown. It's only wrong by a

dimension you can't see.

The embedder now travels *inside* the single cartridge file — same one-file,

binary-only format, no sidecar. On load it's restored, and every read (and every

newly-learned fact) is embedded with the **same** model the stored vectors were

built with. We also added a dimension guard: if an old cartridge ever mismatches,

recall degrades to keyword search instead of returning garbage.

Result: "import any docs → your agent answers from them" now survives close,

reopen, and a week later.

Free for personal use, local and private: [neonmem.com](https://neonmem.com)

(Windows + Linux AppImage).