COG: The Agentic Second Brain That Actually Self-Evolves

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 • Antigravity • Cursor • Kiro • Gemini CLI • OpenAI Codex • any AI that reads markdown

Inspired by Garry Tan's gstack and gbrain

graph LR
    A[You] -- natural language --> B[AI Agent]
    B -- runs --> C[43 Skills]
    C -- delegates to --> W[6 Workers]
    C -- verified by --> V[4 Read-Only Verifiers]
    C -- reads & writes --> D[.md Files]
    W -- reads & writes --> D
    V -- observes --> D
    C -- syncs with --> G[GitHub / Linear / Slack / PostHog]
    D --> E[Git]
    D --> F[iCloud]

Quick Start

1. Clone & enter the repo:

git clone https://github.com/huytieu/COG-second-brain.git
cd COG-second-brain

2. Run onboarding in your agent:

Agent	Command	How it finds skills
Claude Code	code . → "Run onboarding"	.claude/skills/
Antigravity	Open folder → "Run onboarding"	.agents/skills/ + .agents/rules/cog.md
Cursor	Open folder → "Run onboarding"	.cursor-plugin/ + .cursorrules
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

Or install via skills.sh:

npx skills add huytieu/COG-second-brain

Done — COG is personalized and ready in ~2 minutes. See SETUP.md for optional config (Git sync, iCloud, Obsidian Tasks, etc.).

Agent Support Matrix

COG ships a full Claude Code surface, a full Antigravity surface, plus core native surfaces for Kiro and Gemini CLI, with AGENTS.md as the universal fallback for Codex and other markdown-reading agents.

Surface	Current support	Notes
Claude Code	33 native skills + 10 agents (6 workers + 4 verifiers)	Full first-class surface
Antigravity	43 skills + 10 agents (pointer-stub format)	Full surface — thin stubs in .agents/ delegate to the .claude/ playbooks, which stay authoritative
Agent Plugins standard	Root plugin.json + skills/ (43 skills)	Spec 1.0.0 conformant; any standard-aware client loads COG as a plugin
Cursor	Plugin manifest + rules	.cursor-plugin/plugin.json + .cursorrules
Kiro	7 native powers	Core workflows today
Gemini CLI	7 native commands	Core workflows today
AGENTS.md	33 documented commands	Universal fallback for Codex and other agents

Before publishing or updating framework files, run ./scripts/validate-agent-surface.sh to catch drift between manifests, docs, and shipped files. See docs/AGENT-SUPPORT.md for the detailed support matrix and contributor rules.

Skills

Core Skills (Personal Knowledge)

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"
memory-hygiene	Trust sweep of persistent memory — re-verify claims against the live environment, stamp last_verified + confidence	"Audit my memories"

Team Intelligence Skills (for Product & Engineering Leads)

Skill	What it does	Try saying...
team-brief	Cross-reference GitHub + Linear + Slack + PostHog into a daily team intelligence brief with two-way Linear sync-back	"Team brief" / "What did we ship?"
meeting-transcript	Process meeting recordings into structured decisions, action items, and team dynamics	"Process this meeting"
comprehensive-analysis	Deep 7-day analysis for weekly reviews, board prep, or strategic planning (~8-12 min)	"Weekly analysis" / "Board prep"

This is the beginning of the README. Read the rest at the original. Read the full README ↗