Cognition + Obsidian + Git — A self-evolving second brain powered by AI agents, markdown files, and version control. No database, no vendor lock-in — just .md files that think.
Quick Start | Skills | Features | FAQ | SETUP.md
Works with Claude Code • Kiro • Gemini CLI • OpenAI Codex • any AI that reads markdown
graph LR
A[You] -- natural language --> B[AI Agent]
B -- runs --> C[7 Skills]
C -- reads & writes --> D[.md Files]
D --> E[Git]
D --> F[iCloud]
New to COG? Watch the 2-minute walkthrough to see it in action.
1. Clone & enter the repo:
git clone https://github.com/huytieu/COG-second-brain.git
cd COG-second-brain2. Run onboarding in your agent:
| Agent | Command | How it finds skills |
|---|---|---|
| Claude Code | code . → "Run onboarding" |
.claude/skills/ |
| Kiro | Open folder → "setup COG" | .kiro/powers/ |
| Gemini CLI | gemini → /onboarding |
GEMINI.md + .gemini/commands/ |
| OpenAI Codex | codex → "Run onboarding" |
AGENTS.md |
| Other agents | Point at AGENTS.md → "Run onboarding" |
AGENTS.md |
Done — COG is personalized and ready in ~2 minutes. See SETUP.md for optional config (Git sync, iCloud, Obsidian Tasks, etc.).
| Skill | What it does | Try saying... |
|---|---|---|
| onboarding | Personalize COG for your workflow (run first!) | "Run onboarding" |
| braindump | Capture raw thoughts with intelligent classification | "I need to braindump" |
| daily-brief | Verified news intelligence (7-day freshness) | "Give me my daily brief" |
| url-dump | Save URLs with auto-extracted insights | "Save this URL" |
| weekly-checkin | Cross-domain pattern analysis | "Weekly review" |
| knowledge-consolidation | Build frameworks from scattered notes | "Consolidate my knowledge" |
| update-cog | Update framework files without touching your content | "Update COG" |
graph TD
A[Daily: Braindump thoughts] --> B[Daily: Intelligence briefing]
B --> C[Weekly: Pattern analysis]
C --> D[Monthly: Knowledge consolidation]
D -- COG learns your patterns --> A
- Daily capture — braindump raw thoughts; COG classifies by domain and extracts action items
- Daily intelligence — personalized briefings with verified, sourced news
- Weekly reflection — pattern analysis across all domains surfaces insights you'd miss
- Monthly synthesis — scattered notes become consolidated frameworks and a knowledge base
| Self-Evolving — Learns your patterns, auto-organizes content, builds frameworks | Self-Healing — Rename files or restructure; cross-references update automatically | Verification-First — Sources required, 7-day freshness, confidence levels on all analysis |
Privacy-First — Local .md files, strict domain separation, no external servers |
Multi-Device — iCloud sync to iPhone/iPad/Mac; Git for version history | Obsidian Tasks — 📅 YYYY-MM-DD emoji format works with Tasks plugin dashboards |
COG-second-brain/
├── .claude/skills/ # Claude Code skills
├── .kiro/powers/ # Kiro powers
├── .gemini/commands/ # Gemini CLI commands
├── AGENTS.md # Universal agent docs
├── 00-inbox/ # Profiles & onboarding files
├── 01-daily/ # Briefs & check-ins
├── 02-personal/ # Personal braindumps (private)
├── 03-professional/ # Professional braindumps & strategy
├── 04-projects/ # Per-project tracking
└── 05-knowledge/ # Consolidated insights & patterns
Real-world results: 120+ braindumps processed, daily briefs with 95%+ source accuracy, 5 major strategic insights discovered — zero maintenance required.
COG separates framework files (skills, docs, scripts) from your content (braindumps, profiles, notes). Updates never touch your personal data.
| Method | Command |
|---|---|
| AI Agent (any) | "Update COG" or /update-cog |
| Shell script | ./cog-update.sh (interactive) • --check • --dry-run • --force |
| Manual Git | git fetch cog-upstream main then checkout specific files |
Check your version: cat COG-VERSION
Why not just use Notion / Roam / Obsidian alone?
COG adds self-evolving intelligence on top. It doesn't just store — it learns, analyzes, and synthesizes insights automatically.
How much does it cost?
COG is free and open-source (MIT). You only pay for your AI agent's API usage.
Is my data private?
Yes. Everything is local markdown files. The AI agent's API is only called when you invoke a skill. No data stored on external servers.
Can I customize or add skills?
Yes — edit any SKILL.md / POWER.md / AGENTS.md file. See SETUP.md for details on creating new skills.
Will updating overwrite my customizations?
No. The update process detects customized files and lets you choose per-file: keep yours, use upstream, or backup + update. Nothing is overwritten without approval.
What if I don't use Git?
Git is optional but recommended for version history. COG works fine with just iCloud sync.
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Gemini CLI + OpenAI Codex support(shipped in v3.1) -
Upstream update system(shipped in v3.2) - Web interface for knowledge graph visualization
- Mobile-first commands (optimized for Obsidian mobile)
- Team collaboration features (with privacy preservation)
- Integration with calendar/task management tools
| Contribute | Report bugs | Discussions |
| Sponsor on GitHub | Buy me a coffee | MIT License |
Built with Claude Code, Kiro, Gemini CLI, OpenAI Codex, and Obsidian. Inspired by Zettelkasten, Building a Second Brain, and GTD.
TL;DR: Clone, run onboarding, braindump daily. COG evolves with you — just .md files, any AI agent, zero maintenance.
