Default plan
Open source
Free
- Skills
- Agents
- People CRM
CS
AIOS Market editorial rating
Our own assessment, scored on published criteria. Separate from buyer reviews.
7.5 / 10
Full operating system (installed)Usefulness: 3 Capable
Definition and evidence
Agents that do multi-step work when asked.
Evidence: Skills and worker agents with verifiers and persistent markdown memory; no documented scheduled runs
- Autonomy weight 15%
- 5 / 10
- Depth weight 15%
- 8 / 10
- Ease of setup weight 15%
- 6 / 10
- Ownership and privacy weight 10%
- 10 / 10
- Value for money weight 15%
- 9 / 10
- Updates and support weight 10%
- 9 / 10
- Security weight 10%
- 7 / 10
- Maturity and traction weight 10%
- 7 / 10
A free second-brain system with skills, worker agents, verifiers and persistent markdown memory, with an active maintainer and a solid following. It works when you ask rather than on a schedule. One of the better free knowledge systems for people who want to own their notes.
Security: Passed with warnings. Scanned on 2026-10-05 with ClamAV, YARA, gitleaks and OSV: no malware or leaked secrets found. Our pattern rules flagged 2 items for review, such as prompt.hide-actions, prompt text that overrides the user.
Rated on
The facts
As stated by the maker. Anything missing is marked Not stated.
- Delivery
- Installs on your machine
- GitHub
- 1,255 GitHub stars
- Runs on
- macOS, Linux, Windows
- Works with
Claude Code, Cursor, Gemini CLI, Codex, Kiro, Antigravity... Read more
Claude Code, Cursor, Gemini CLI, Codex, Kiro, Antigravity- You'll need
- Not stated
- Install
- git clone then ask your agent to run onboarding, or npx skills add
- Install time
- About 2 minutes (stated)
- Difficulty
- Moderate
- Company size
- Solo, 2-10
- Updates
- Not stated
- Licence
- MIT
- Seats included
- Not stated
- Team sharing
- Not stated
- Integrations
- Not stated
- Data
- Plain markdown files in your own repo
- Support
- GitHub issues
- Industries
- Functions
- Checks
- Security review: not completed. Automated checks, not a guarantee.
What it takes off your plate
An open-source second brain made of markdown files, Obsidian and git. It ships 33 to 35 skills, six worker agents, four read-only verifiers and a people CRM. It works with Claude Code and several other agent CLIs.
Read the full description
What it is. An open-source second brain made of markdown files, Obsidian and git. It ships 33 to 35 skills, six worker agents, four read-only verifiers and a people CRM. It works with Claude Code and several other agent CLIs.
Pricing. Free, MIT licence Licence. MIT Where it runs. Claude Code, Cursor, Gemini CLI, Codex, Kiro, Antigravity
Facts checked on 2026-10-06 from the maker's own site: https://github.com/huytieu/COG-second-brain. Not stated by the maker on that date: scheduling.
What's inside
No agent breakdown has been provided.
Plans
1 plan
Prices are the maker's, as published on their site on Oct 6, 2026. Buy on the maker's site.
Buyer reviews
No buyer reviews yet
Buyer reviews open when the maker sells here.
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COG Second BrainVisit official site