---
slug: "cog-second-brain"
source_type: "readme"
source_url: "https://cdn.jsdelivr.net/gh/huytieu/cog-second-brain@main/README.md"
repo: "https://github.com/huytieu/cog-second-brain"
source_file: "README.md"
branch: "main"
---
# 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](#quick-start) | [Skills](#skills) | [Features](#features-at-a-glance) | [FAQ](#faq) | [SETUP.md](https://github.com/huytieu/cog-second-brain/blob/HEAD/SETUP.md)
> Works with [Claude Code](https://claude.ai/download) • [Cursor](https://cursor.com/) • [Kiro](https://kiro.dev/) • [Gemini CLI](https://github.com/google-gemini/gemini-cli) • [OpenAI Codex](https://github.com/openai/codex) • any AI that reads markdown
>
> Inspired by [Garry Tan's gstack](https://github.com/garrytan/gstack) and [gbrain](https://github.com/garrytan/gbrain)
```mermaid
graph LR
A[You] -- natural language --> B[AI Agent]
B -- runs --> C[21 Skills]
C -- delegates to --> W[6 Worker Agents]
C -- reads & writes --> D[.md Files]
W -- reads & writes --> D
C -- syncs with --> G[GitHub / Linear / Slack / PostHog]
D --> E[Git]
D --> F[iCloud]
```
> **New to COG?** Watch the [2-minute walkthrough](https://youtube.com/PLACEHOLDER) to see it in action.
## Quick Start
**1. Clone & enter the repo:**
```bash
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/` |
| 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](https://skills.sh):**
```bash
npx skills add huytieu/COG-second-brain
```
Done — COG is personalized and ready in ~2 minutes. See [SETUP.md](https://github.com/huytieu/cog-second-brain/blob/HEAD/SETUP.md) for optional config (Git sync, iCloud, Obsidian Tasks, etc.).
## Agent Support Matrix
COG ships a **full Claude Code 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 | 21 native skills + 6 worker agents | Full first-class surface |
| 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` | 21 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](https://github.com/huytieu/cog-second-brain/blob/HEAD/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" |
### PM Workflow Skills (for Product Managers)
| Skill | What it does | Try saying... |
|---|---|---|
| **create-user-story** | Create user stories with duplicate checking across Linear, GitHub Issues, or Jira | "Create a user story for..." |
| **generate-prd** | Draft PRDs with approval gate before publishing to Confluence/Notion | "Generate a PRD for..." |
| **generate-release-notes** | Generate release notes from GitHub milestones, Linear cycles, or manual input | "Generate release notes for v2.1" |
| **export-open-issues** | Audit and export open issues from any tracker into a structured vault summary | "Export open issues" |
| **publish-to-confluence** | Publish any vault markdown file to Confluence | "Publish this to Confluence" |
| **update-knowledge-base** | Maintain product knowledge base from releases, features, and project changes | "Update the knowledge base with v2.1 changes" |
> **PM Workflow:** These skills form a complete product management lifecycle: **Research** (`/auto-research`) → **PRD** (`/generate-prd`) → **Stories** (`/create-user-story`) → Development → **Release Notes** (`/generate-release-notes`) → **Knowledge Base** (`/update-knowledge-base`). Use `/export-open-issues` for audits and `/publish-to-confluence` to share externally.
### Strategic Research
| Skill | What it does | Try saying... |
|---|---|---|
| **auto-research** | Deep strategic research engine — decomposes questions into parallel research threads with multiple agents | "Research the future of AI testing tools" |
### Content Creation
| Skill | What it does | Try saying... |
|---|---|---|
| **content-factory** | Autonomous content pipeline — scout announcements, triage by trend momentum + your unique angle, publish with ledger dedup, hard volume caps, and screenshot-verified posting | "Run the content factory" |
### Worker Agents (Specialist Sessions)
COG uses a worker agent architecture inspired by [garrytan/gstack](https://github.com/garrytan/gstack) specialist sessions and [garrytan/gbrain](https://github.com/garrytan/gbrain) knowledge patterns. Workers handle data-heavy tasks cheaply (Sonnet) while the lead session does reasoning (Opus).
| Agent | What it does | Model |
|---|---|---|
| **worker-data-collector** | Structured extraction from GitHub, Slack, Jira, Linear | Sonnet |
| **worker-researcher** | Web research with source citations | Sonnet |
| **worker-file-ops** | Vault file operations, metadata, profiles | Sonnet |
| **worker-executor** | Pre-approved mutations (Jira, Linear, APIs) | Sonnet |
| **worker-publisher** | Publishing to Slack, Confluence, Notion | Sonnet |
| **brief-people-updater** | Batch-update people profiles from meetings/briefs | Sonnet |
> Workers write results to `/tmp/` files and return only a status + path. The lead reads the file for synthesis. This eliminates slow token generation in agent output.
### People CRM (Knowledge-Based Team Profiles)
Track the people you work with using progressive, evidence-based profiles in `05-knowledge/people/`. Profiles auto-escalate via tiered enrichment:
- **Tier 3 (Stub)** — 1 mention: name, role, one-line context
- **Tier 2 (Moderate)** — 3+ mentions: executive snapshot, working style, strengths
- **Tier 1 (Full)** — 8+ mentions or direct meeting: complete profile with all sections
Every observation includes a source citation with confidence level. See `05-knowledge/people/README.md` for details.
### Role Packs (Personalized Recommendations)
COG matches your role during onboarding to a **role pack** that prioritizes the most relevant skills and integrations for you. Available role packs: Product Manager, Engineering Lead, Engineer, Designer, Founder, Marketer — or create your own from the template.
> **New to team skills?** These require GitHub CLI (`gh`) and work best with Linear, Slack, and PostHog MCP integrations. They degrade gracefully — start with just GitHub and add integrations over time. See [SETUP.md](https://github.com/huytieu/cog-second-brain/blob/HEAD/SETUP.md) for configuration.
## The Evolution Cycle
```mermaid
graph TD
A[Daily: Braindump thoughts] --> B[Daily: News intelligence]
A --> T[Daily: Team intelligence brief]
M[Meetings: Process transcripts] --> T
T -- syncs back to --> L[Linear / GitHub]
B --> C[Weekly: Pattern analysis]
T --> CA[Weekly: Comprehensive analysis]
C --> D[Monthly: Knowledge consolidation]
CA --> D
D -- COG learns your patterns --> A
R[Strategic: Auto-research] --> P[PM: Generate PRD]
P --> S[PM: Create user stories]
S -- after development --> RN[PM: Release notes]
RN --> KB[PM: Update knowledge base]
```
- **Daily capture** — braindump raw thoughts; COG classifies by domain and extracts action items
- **Daily intelligence** — personalized news briefings with verified, sourced news
- **Daily team brief** — cross-reference GitHub, Linear, Slack, PostHog, meetings into one brief with two-way sync
- **Meeting processing** — extract decisions, action items, and team dynamics from transcripts
- **Weekly reflection** — pattern analysis across all domains surfaces insights you'd miss
- **Weekly deep dive** — comprehensive analysis for board prep, retros, and strategic planning
- **Monthly synthesis** — scattered notes become consolidated frameworks and a knowledge base
- **Strategic research** — deep multi-agent investigation of strategic questions with real sources
- **PM workflow** — full product lifecycle from PRD to release notes to knowledge base updates
## Features at a Glance
| | | |
|---|---|---|
| **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 |
| **Garry Tan Inspired** — gstack specialist sessions + gbrain knowledge patterns | **Multi-Platform** — Listed on [skills.sh](https://skills.sh), [agentskill.sh](https://agentskill.sh), [cursor.directory](https://cursor.directory) | **Worker Agents** — Sonnet handles I/O, Opus handles thinking |
| **Runtime Trust** — memory hygiene sweeps re-verify stored facts against the live environment | **Post-Condition Checks** — mutating skills observe the artifact before reporting success | **Skill Distillation** — [explore once, execute cheap](https://github.com/huytieu/cog-second-brain/blob/HEAD/docs/SKILL-DISTILLATION.md) with small models |
## Your Vault
```
COG-second-brain/
├── .claude/skills/ # Claude Code skills (21)
├── .claude/agents/ # Worker agent definitions (6)
├── .claude/roles/ # Role packs (7) — personalized recommendations
├── .kiro/powers/ # Kiro powers
├── .gemini/commands/ # Gemini CLI commands
├── AGENTS.md # Universal agent docs
├── CLAUDE.md # Framework instructions
├── 00-inbox/ # Profiles, interests, integrations
├── 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
│ └── people/ # People CRM profiles
└── 06-templates/ # Document templates
```
> **Real-world results:** 120+ braindumps processed, daily briefs with 95%+ source accuracy, 5 major strategic insights discovered — zero maintenance required.
## Keeping COG Updated
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`
Validate packaged surfaces: `./scripts/validate-agent-surface.sh`
## FAQ
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](https://github.com/huytieu/cog-second-brain/blob/HEAD/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.