Second Brain Update: Bigger Imports, Faster Pages, and the Cowork Question I Keep Getting

New build is live. Changelog is at the bottom. First, the question I keep getting about Claude Cowork: if Claude can already work through my files, why do I need this?

Second Brain stores records, not documents

Everything imports into one local SQL database on your machine. Contacts become rows with columns. Stripe and PayPal history becomes transactions tied to those contacts. Calendar events link to participants by email. Word docs and PDFs go in the same database, not as files sitting in a folder. Nothing is a note about a customer. It is the customer, with keys the software understands.

Claude reaches it through MCP with three tools: read the schema, run a query, write rows back. It sees what tables exist, writes SQL, gets the matching rows. When you want the output kept, it writes into the same tables, so the next session starts where the last one finished.

That means you can ask things nobody built a report for. Which customers paid in 2025 and went quiet in 2026. Who I met with last quarter that never bought anything. What one contact has spent across every payment method I have used.

Documents work the same way

Import splits each file into ordered sections with headings, stores them as rows, tags them, and indexes every word for search. So a 200-page manuscript is not one blob you have to load. It is a few hundred sections Claude can address one by one. It searches for the term, pulls the six sections that contain it, and reads those. Fifty documents behave the same as one, because you are pulling paragraphs instead of files.

What Cowork does

Cowork points Claude at a folder. You describe an outcome and it plans the steps, opens files, runs code, writes results.

Two costs come with that design. Everything it reads passes through the context window, so a question touching thirty files costs thirty files worth of tokens even when the answer lived in one of them. And when it writes, it writes files. It can edit a document or produce a new one, but there is no record underneath to update, so the next session opens everything again instead of picking up where the last one stopped. Second Brain writes rows. Ask it to tag fifty contacts and those tags are in the table, ready for the next query, and no file was rewritten to get there.

Where they split

Selection. A query has a WHERE clause. It returns every matching row and nothing else. An agent reading a folder has to decide which files to open and what to skip once the material outgrows the context window. You never see that decision, and it sets your answer.

Consistency. Same query, same rows, next month too. A pass through a folder depends on phrasing, on what turned up first, on where the window filled. Ask twice, get two answers, both confident.

Tokens. SQL counts, filters, and joins before Claude sees anything. Ask which clients went quiet and it reads 12 rows, not 40,000. The database can be gigabytes while the answer stays a few hundred tokens.

Speed. An index walks straight to matching rows instead of scanning the table. A lookup across 100,000 words lands in milliseconds.

Location. Cowork sessions run on Anthropic’s servers, and local files opened through the desktop app are processed there too. Second Brain keeps the database on your machine. Only the rows a query returned leave it.

I am not going to tell you which one you need. Look at the questions you actually ask in a normal week and judge for yourself which shape they fit. I know my answer for my data. Yours may land somewhere else.

What shipped

Importing files. Better tagging, clearer messages, and faster.

More you can bring in. You can now import emails from a CSV. CSV files from your computer can be up to 32 GB.

Database Cleanup. It now repairs broken links between records and tells you what it fixed.

Faster. Dashboard and Import load noticeably quicker, and Contacts has more ways to filter.

Plus a long list of smaller interface and performance work across settings, contacts, and the import page.

Update at brain.hexact.io.

If you have not imported anything yet, start with one thing. Export your contacts to CSV, or pull the zip from Google Calendar settings, and drop it on the Import page. Then ask Claude something you could not ask before. One query explains this better than I can in writing.

If you want me to walk you through it, book a call. I will show you what to import first for your use case and where the useful queries come from. I run these myself, so bring the hard questions.