The documentation assistant

Railbase ships a built-in assistant that answers questions about your instance and the modules installed on it. It is deliberately narrow: it answers from an indexed documentation corpus — the product documentation embedded in the core (this very guide, indexed automatically on first start), the docs your installed plugins shipped, plus whatever an operator indexes — it cites the passages it used, and when nothing in that corpus matches it says so instead of guessing.

Two audiences, two places

The assistant appears twice, because the two audiences read different documentation.

Who	Where	Sees
Administrators	The floating assistant button (bottom-right on every admin page)	Docs written for the admin audience
Everyone else	The site at /assistant (sidebar entry Assistant)	Docs written for the site audience

In the admin panel the assistant is a companion, not a destination: the round button in the bottom-right corner opens it in a side panel wherever you are, so you can ask about the screen you are on without leaving it. On the site, /assistant is a reserved route — no installed plugin can take that URL — and it requires a signed-in app user; an anonymous request is rejected.

A doc entry declares its audience as admin, site, or both. Entries marked both are answerable from either place; the others stay on their own side. That is why an operator and a member of staff can ask the same question and get answers drawn from different material.

What it answers from

The corpus is built from the documentation inside the plugin bundles you have installed. A bundle's manifest declares its docs in a docs array, and on a successful install the core indexes every entry that carries its text inline in the manifest — chunking it, embedding it, and storing it in your Vault. There is no separate ingest step, no rebuild, and nothing to switch on. Ask a question right after installing such a module and its docs are already answerable. An entry that only names a file shipped alongside the manifest is skipped by auto-ingest; index that text yourself from Settings → AI → Docs (see below).

Indexed plugin docs are stored tenant-less, so they answer for every company on a multi-tenant instance. Anything indexed against a specific tenant is only retrieved for that tenant.

When you uninstall a plugin, its indexed documentation is removed with it, so the assistant stops answering from — and citing — a module that is no longer there.

Answers carry citations

Every grounded answer comes back with its sources listed beneath it, under a Sources heading. Each entry shows the document it came from — plugin docs are identified as <slug>:<path>, for example compliance:docs/admin.md — and the plugin that shipped it; the site also shows the document's title.

By default the assistant retrieves the six best-matching passages for your question and answers from those. The citations tell you exactly which ones, so you can go and read the original before acting on the answer.

It refuses rather than guesses

If retrieval finds nothing relevant, the assistant does not call the language model at all. It returns a fixed refusal:

I don't know based on the available documentation.

The admin console marks that reply No matching documentation; the site marks it No matching source — answering from general knowledge is disabled. The refusal is structural, not a matter of prompt wording: with no retrieved passage there is no generation step, so there is nothing to hallucinate from.

Conversations

The assistant is a thread, not a one-shot form. Each answer is recorded with the question that produced it, and the next turn is asked with recent history in view — so follow-ups that lean on pronouns work:

1. "When do backups run?"
2. "Can I change that?" — "that" resolves against the previous turn.

The model sees a short rolling window of the last six messages, so a long thread never bloats the request. The stored thread keeps far more of the history for you to read back, and is capped at 200 messages, with the oldest trimmed away beyond that. Retrieval still runs fresh on every turn: each new question is grounded and cited on its own.

Controls on both surfaces:

• New conversation starts a fresh thread.
• Recent conversations lists your threads, newest first; click one to reload it with its full history.

Deleting a thread is an API operation — DELETE /api/ai/assistant/conversations/{id} on the site, DELETE /api/_admin/ai/conversations/{id} in the admin console. Neither screen shows a delete button.

Threads are owner-scoped. A conversation belongs to one tenant, one surface (admin or site), and one person. An administrator cannot open an app user's thread, an app user cannot open an administrator's, and one user cannot open another's — a thread that is not yours reads as not found, not as forbidden.

Retrieval works without an embedding model

Retrieval normally depends on an embeddings-capable model, and many providers — including the Mac's built-in Apple model — offer chat but no embeddings. Railbase therefore ships a built-in lexical embedder (railbase-lexical) and falls back to it whenever no embedding-capable backend is connected. It matches on whole words plus character trigrams, so it holds up on keyword-heavy technical documentation and on inflected languages, where different forms of the same word still match.

The practical effect: plugin docs are indexed and searchable out of the box, with no model provider connected at all.

Producing the written answer is a separate step, and that one does need a connected model provider — set one up under Settings → AI → LLM (bring your own key, or point at a local OpenAI-compatible endpoint). Without one, the assistant returns an error rather than an answer.

Managing the corpus

Settings → AI → Docs shows the indexed corpus: every indexed source with its chunk count. From the same screen an operator can:

• Index a document by supplying a source id, an optional title, an audience (admin, site, or both) and the text — useful for your own house rules or internal runbooks that no plugin ships.
• Remove a source from the corpus.

Anything you index there becomes answerable and citable exactly like plugin documentation.