The Brain is the agent's long-term memory, kept as readable pages you can browse and edit at Library > Brain. When the agent learns something while working with you (what a campaign is for, a correction you made, a competitor insight) it writes it down here, and reads it back in later conversations. That is why you never have to explain the same thing twice.
The tiers
Client: knowledge about this specific brand: its campaigns, competitors, strategy notes and logs.
Agency: knowledge shared across all your clients: your playbooks, standards and ways of working. Write it once, and every client's agent applies it.
The agent also reads a read-only reference library maintained by Adside, with advertising concepts and best practices, so it does not relearn what CBO is from scratch.
Working with it
Browse the page tree and open any page; it is plain, readable text.
Edit or correct pages directly, or tell the agent in chat and it updates the Brain itself.
Upload documents with the Upload to brain button: strategy docs, personas, brand guidelines. They are ingested so the agent can use them.
Tip: the fastest way to make Adside feel like a team member who has been around for a year is to upload the three documents you would give a new hire.