What is a second brain?
The second-brain idea, popularized by Tiago Forte, is simple: keep an external system for everything you read, learn, and decide, so your biological brain doesn't have to hold it all. Articles, highlights, notes, decisions—all go into one place you can search later. The promise is less cognitive load and better recall.
Traditionally, only you could search that system. You'd open the app, type a query, read the result. The information stayed locked behind a human interface. Your AI tools had no way in. That is changing. A second brain can now be machine-readable, meaning agents can query it the same way you do.
How do AI agents read your second brain?
KnowMan exposes an MCP server with six tools that make your library machine-readable: kb_search (search everything saved), kb_get_item (read full text of a saved item), kb_ask (ask a question, get an answer with citations), kb_memories (read decisions, playbooks, facts, notes), kb_recent (see recent saves), and kb_save (save a new link). Each tool maps to something you'd do manually—search, open, ask, review notes, check recent, bookmark.
Setup: create an agent key in Settings with only the permissions you choose, paste one config snippet into your client. Works with Claude Desktop, Claude Code, Codex, Cursor, and any MCP client. Every new account starts with 14 days of Pro, no credit card. After that, keep Free or upgrade.
Why does a machine-readable second brain matter?
The practical difference: without machine-readable access, every AI session starts blank. You paste context manually, hope you remembered the right article, and lose track of decisions. With MCP access, an agent can search your entire library in seconds, pull the exact source, and cite it. Your second brain becomes active infrastructure, not a passive archive.
KnowMan reads the full text of what you save, not just the title. Answers cite the saved sources so you can verify them. kb_memories surfaces decisions with their reasons, so an agent can remind you why you chose a particular approach six months ago.
What can agents do—and what can they not do?
Agents can read your library, search it, ask it questions with citations, check your Memories for decisions and playbooks, see what you saved recently, and save new links via kb_save. That covers most research and recall tasks. An agent helping you draft a proposal can pull the exact article you saved three weeks ago.
What agents cannot do: write Memories. Memories—decisions with their reasons, playbooks, facts—are created by you. Agents read them; they do not overwrite or add to them. This keeps your knowledge base authoritative. You decide what gets remembered. The boundary is deliberate: agents assist recall, you control the record.
Free plan gives you 5 questions a day with citations, keyword search, unlimited saving, import from Pocket, Instapaper, Omnivore, Readwise, Wallabag, or browser bookmarks, Memories, and MCP connection. Pro removes the daily question limit, adds semantic search, AI summaries, rules that sort articles, newsletter subscriptions, and export to Obsidian, Logseq, or EPUB.
Questions people ask
Who popularized the second-brain concept?
Tiago Forte popularized the term. The core idea: build an external system to capture, organize, and retrieve what you learn, so your mind is free for thinking rather than storing. KnowMan applies this idea and extends it so AI agents can query the same system.
Can AI agents write to my Memories?
No. Agents can read Memories—decisions, playbooks, facts, notes—but cannot write or modify them. You create Memories. Agents consume them for context. This keeps your knowledge base authoritative.
Which AI clients work with KnowMan's MCP server?
Claude Desktop, Claude Code, Codex, Cursor, and any MCP-compatible client. Create an agent key in Settings, paste one config snippet, and the connection is live. You control permissions.
Do I need a paid plan to connect agents?
No. Free plan includes MCP connection. You get 5 questions a day with citations, keyword search, unlimited saving, and Memories. Pro removes the daily limit and adds semantic search, AI summaries, and export.
What happens after the 14-day Pro trial?
You keep the Free plan—5 questions a day, keyword search, unlimited saving, Memories, MCP connection. Or upgrade to Pro for $12.99 per month or $99 per year. Founding rate is $59 per year for the first 500 subscribers.