Company Brain overview

A brain gathers documents around one topic: a handbook, contracts, a project. You decide who may use it and switch it on in a chat. The model then looks for the relevant passages in the documents and names the sources of its answer.

How a brain works

At Kieselmatt Treuhand AG, Lea Keller has created the brain "Firm handbook". It holds the "Fee Schedule 2026", the "Expense Policy 2026", the "Client Communication Guide" and the "New Client Checklist". When someone asks in a chat "Which allowance applies to lunch with a client?", this happens:

Processing. When a file is added, it is converted to text, given a title and a short summary, and prepared for search. This runs in the background.
Finding. For every message, Custodos looks for the relevant passages, not whole files. If that is not enough, the model runs a targeted search of its own.
Answering with sources. The answer refers to the passages it used with [1], [2]. Below the answer you open the list of sources and jump straight to the document.

Access is checked again with every message. Anyone who may not read a brain gets no answers from it, not even through an agent or a project.

Brain, attached file or agent file?

	Attach a file in a chat	An agent's files	Company Brain
Meant for	one question about one document, now	templates an agent needs in every chat	knowledge many people need again and again
Who uses it	you, in this chat	everyone who uses the agent	everyone with access to the brain
What the model reads	the whole text, with every message	the whole text, in every chat with the agent	only the relevant passages
Volume	individual files	up to 10 files	hundreds of documents
Sources in the answer	no source list	no source list	numbered and clickable
Keeping it current	attach again	replace it in the agent	upload a new version or refresh from the source

As a rule of thumb: attach a file for a one-off question (Attaching files and images). Give an agent what it needs as a template (Configuring an agent). What your team looks up again and again belongs in a brain.

Good to know

Every member can create a brain. During a trial, Company Brain is locked and becomes available with your first plan.
Processing counts towards usage: the brain page puts it at about 0.5 credits per 20 pages. It is booked to the person who adds the document.
Every brain has its own data protection level. It applies independently of the workspace's protection mode.