What's new in Second Brain: expanded email archives, custom datasets, and fixes
We shipped a new version this week. Here is what changed.
Email archive import: more formats, much bigger files
Email archive import was already in Second Brain. This update expands it significantly. We added support for more file types and removed the size limits that were blocking larger archives. If you tried importing before and hit a wall, try again.
Supported formats now include .eml, .mbox, .zip containing .eml files, and .pst for Outlook. The dry run option lets you preview the import before it runs, which is useful when you are dealing with a large archive and want to know what you are working with first.
Custom datasets
You can now create named datasets and import any CSV file into Second Brain. Price lists, product catalogs, inventory, whatever structured data you work with regularly. You can have multiple datasets and manage them independently.
Deduplication is handled by ID. Re-import an updated file and existing records get updated, not duplicated. Update your catalog, re-import, done.
Claude can query any dataset directly in conversation. Ask about your prices, look up a product, cross-reference a price list. No manual copying, no context window gymnastics.
Second Brain as a source of truth
The core idea behind Second Brain is that Claude should always have accurate, current context about your business without you having to paste it in every time. You build the knowledge base once, keep it current, and Claude works from it.
It works both ways. Claude reads from your knowledge base to answer questions and help you make decisions. You can also ask Claude to update records, retag entries, reorganize datasets. The app and Claude are two ways to manage the same data. As your business evolves, your knowledge base evolves with it.
Bug fixes and performance improvements
This release also includes:
Bug fixes across import pipelines and dashboard rendering
Better handling of large file imports without timeouts
Stability improvements for MCP connectivity
General performance improvements across the app
If you are on an older version, the update is worth it.
Download the latest version — available on macOS and Windows.
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