Open Second Brain MCP
Local agent memory stores findings and rules in Obsidian-compatible Markdown files with search and controls for recorded changes.
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- Last commit
- MIT
Extended access
Why this level
- MCP and hooks read notes and store memory, rules and changes in a local vault.
Install
- Works in
Manual install
git clone https://github.com/itechmeat/open-second-brain ~/open-second-brain
~/open-second-brain/scripts/o2b install-cli
export PATH="$HOME/.local/bin:$PATH"
o2b versionThe first Get the o2b CLI block in README-linked install/prerequisites.md. Prepare Bun first; init then creates the vault.
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- MCP and hooks read notes and store memory, rules and changes in a local vault.
This is third-party code. Review the repository files before installing.
What it does
Open Second Brain adds shared agent memory to an Obsidian vault. MCP servers, hooks and a CLI read and write through one core. Agent material lives as Markdown under Brain, with a search index rebuildable from those files. A separate dream pass turns repeated signals into rules and retires unused ones. It follows a deterministic algorithm without its own model. Attributed writes and snapshots let users inspect changes and restore earlier state.
Who it is for. For users of several AI clients retaining knowledge and preferences in a human-readable note vault.
Good fit when
- Restore important rules in a new agent session.
- Keep notes as ordinary Markdown files.
- Inspect which agent changed material.
- Roll back an incorrect write to a snapshot.
Not a fit when
- Bun cannot be installed on the host.
- Agents cannot change notes or memory.
- You expect all retained rules to be automatically true.
Example request
Create a separate Open Second Brain test vault, store one rule and show the author and change snapshot.MCP
- Transport
- stdio
- Authentication
- not required
Limitations
Bun 1.1 or later must be available to the MCP client; there is no Python fallback. The server writes its own material and can edit a note at a named path, so use a separate vault and restrict directory permissions. Local memory does not prevent the host model from receiving retrieved text; follow rules for private notes. Dream uses retained signals, so inspect new preferences and remove incorrect conclusions before they are applied again.
How to disable. Run `o2b uninstall --target <name> --apply` for the client. Remove manually added MCP settings from the client separately. The vault remains; back it up before cleanup.
FAQ
How do I check a vault?
Use `o2b doctor --vault /path/to/vault`.
How do I check client configuration?
Run `o2b install --check`.
Can I stop writes?
`o2b brain freeze` stops memory writers.
Does dream itself require a model?
No. That algorithm is deterministic.
How do I connect another MCP client?
Generic mode prints server configuration for manual client setup.
Discussion
No questions or reviews yet.
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README in short
The core separates Markdown sources from rebuildable SQLite. Client adapters use the same memory, and configuration changes can be previewed.