Which layers you can read and edit yourself
Written memory is the one built to be edited. The Memory tab shows MEMORY.md three ways - an outline of sections and facts, a rendered view, and the raw markdown - and offers two ways to write: a quick-add form that appends a single fact to a section you choose (leave the section blank and it goes into today's daily log instead), and a full editor that replaces the whole file in one save. If the agent changes the file while you have the editor open, a banner says so before you overwrite it. An edit takes effect on the agent's next reply, with no restart. The same files sit in the Files tab and on disk, so a text editor works too.
Because these are files, they have history. Every meaningful change to configuration and markdown files is committed to a revision history and attributed to the agent or person who made it, so you can see what an agent changed in MEMORY.md last Tuesday and what a config looked like before an edit. Two consequences follow. A wrong fact is a one-line fix. And a fact you remove is gone from the agent's next prompt but still visible in the revision history: for conversations, delete removes the state and the transcript; for memory files, it means edited, with a trail. If you have data-deletion obligations, one setting keeps memory files out of that history, because they carry distilled personal data.
The transcript you read rather than edit. It is what the chat view shows when you reopen a conversation, badged with the channel it came from and carrying its running cost. Conversation state you never touch directly; you act on it with /new, /compact, Rename and Delete. The knowledge base is managed from the Knowledge section: add files and URLs, create named stores so different bodies of material stay separate, sync a directory, list what is indexed, remove sources you no longer want.
One variant worth knowing about: where an agent serves many end customers, each customer can be given their own isolated memory rather than one shared file. That is a multi-user setting, covered in multi-user agents.