Writing & notes

second-brain

Drop sources in a folder, get a cross-linked wiki

Visit official page 日本語で詳しく見る

Popularity

★ 679

Last update

April 2026

License / pricing

Not stated

What it does

An implementation of the LLM Wiki pattern: raw articles, papers, notes and transcripts go into a folder, the model compiles them into structured pages with cross-references and a maintained index, and you read the result in Obsidian. The model is the librarian; you stay the curator. Everything you drop in reaches your provider, the bill scales with the pile, and compiled pages drift from what the source actually claimed — the originals stay for exactly that reason. No licence file was found.

Summary based on the project's own description. The Japanese page has a fuller beginner guide: setup difficulty, what to prepare, and a step-by-step start.

Screenshots & visuals

Before you start

Setup difficultySome setup needed
Command lineRequired
API keyRequired
Sends data onlineYes

Judged automatically from the project's own metadata. Always confirm on the official page.

second-brain FAQ

Is second-brain free?: second-brain itself is free, but it needs an API key for an external AI service. That service charges separately, though some have a free tier.
Do I need to install anything or write code to use second-brain?: It needs the command line. If you are not comfortable typing commands, expect to get stuck during setup.
Does second-brain work on a phone?: No. It needs a computer.
Can I use second-brain commercially?: The project does not state a clear licence, so commercial use cannot be confirmed here. Check the official page or ask the author before using it at work.

How it compares

The conditions that decide whether you can actually use it, side by side.

Tool	Command line	API key	Sends data out	Phone	Commercial use
second-brain (this page)	Required	Required	Yes	No	Not verified
Obsidian Copilot	Not needed	Required	Yes	No	Yes
obsidian-smart-connections	Not needed	Not needed	No	No	Not verified
obsidian-agent-client	Not needed	Required	Yes	No	Yes

"Sends data out" means your input is uploaded to someone's server. Pick "No" when the material cannot leave your organisation.

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obsidian-smart-connections

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obsidian-agent-client

Use Claude Code and other agents from inside Obsidian (Japanese docs available)

obsidian-smart-composer

Ask an AI about your own notes, inside Obsidian

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What it does

Summary based on the project's own description. The Japanese page has a fuller beginner guide: setup difficulty, what to prepare, and a step-by-step start.

second-brain FAQ

Is second-brain free?

second-brain itself is free, but it needs an API key for an external AI service. That service charges separately, though some have a free tier.

Do I need to install anything or write code to use second-brain?

It needs the command line. If you are not comfortable typing commands, expect to get stuck during setup.

Does second-brain work on a phone?

No. It needs a computer.

Can I use second-brain commercially?

The project does not state a clear licence, so commercial use cannot be confirmed here. Check the official page or ask the author before using it at work.

How it compares

The conditions that decide whether you can actually use it, side by side.

Tool	Command line	API key	Sends data out	Phone	Commercial use
second-brain (this page)	Required	Required	Yes	No	Not verified
Obsidian Copilot	Not needed	Required	Yes	No	Yes
obsidian-smart-connections	Not needed	Not needed	No	No	Not verified
obsidian-agent-client	Not needed	Required	Yes	No	Yes

"Sends data out" means your input is uploaded to someone's server. Pick "No" when the material cannot leave your organisation.