COG is an AI-assisted second brain that stores knowledge in Markdown files and uses agents, skills, and version control to evolve it over time. It helps people manage knowledge and contacts while supporting several coding-agent tools; the catalogue entries are COG’s skills, agents, instructions, rules, and plugin surfaces.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add huytieu/COG-second-brain --skill weekly-checkingit clone --depth 1 https://github.com/huytieu/COG-second-brainWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/huytieu/cog-second-brain/weekly-checkin)<a href="https://agentmods.dev/skills/huytieu/cog-second-brain/weekly-checkin"><img src="https://agentmods.dev/badge/skills/huytieu/cog-second-brain/weekly-checkin/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/huytieu/cog-second-brain/weekly-checkin"><img src="https://agentmods.dev/badge/skills/huytieu/cog-second-brain/weekly-checkin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00014 | $0.00102 |
| Opus 5 | $0.00007 | $0.00051 |
| Sonnet 5 | $0.00003 | $0.00020 |
| Haiku 4.5 | $0.00001 | $0.00010 |
Grade A, and why
weekly-checkin scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
73% identical to create-user-story — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
Read .claude/skills/weekly-checkin/SKILL.md and execute it exactly as written — that file is the authoritative
playbook. Then follow .agents/rules/cog.md.
Antigravity substitution: where the playbook delegates to a .claude/agents/<name>
worker, invoke .agents/agents/<name>.md via invoke_subagent instead.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 11 lines · 14 tokens per session scan A 04587a2e039f
weekly-checkin is a skill published in the GitHub repository huytieu/COG-second-brain (1,178 stars, last pushed 14d ago), licensed MIT. It adds 14 tokens to every session and 102 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 73% identical to create-user-story, differing in 6 lines, and is treated as a copy.
Other skills, from other repositories
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Google Suite integration for Sheets, Docs, Slides, Gmail, Calendar, Tasks with multi-account support. Orchestrates operations via CLI tools.
ac-tools-cpc
Copy text to clipboard via pbcopy. Triggers on keywords: copy, clipboard, pbcopy, cpc.
ac-workflow-mux
Use this when the task is too large for one uninterrupted context window and you need mux wave semantics with tmux-backed long-lived execution.
tmux
Remote-control tmux sessions for interactive CLIs by sending keystrokes, capturing pane output, and managing terminal multiplexer windows. Enables parallel coding-agent orchestration, background process management, and REPL interaction via sockets. Use when the agent needs to launch, monitor, or coordinate…
things-mac
Manage Things 3 via the things CLI on macOS (add/update projects+todos via URL scheme; read/search/list from the local Things database). Use when a user asks Otto to add a task to Things, list inbox/today/upcoming, search tasks, or inspect projects/areas/tags.
obsidian
Work with Obsidian vaults (plain Markdown notes) and automate via obsidian-cli. Use when the user asks about notes, vault management, PKM, knowledge base organization, wikilinks, or personal knowledge management in Obsidian.