What is second_brain CLAUDE.md?

Project instructions for maintaining a personal knowledge wiki with an AI agent. The wiki combines source files, generated notes, indexes, and topic pages.

Adding sources, creating or updating wiki pages, answering questions from the stored material, and keeping the wiki cross-referenced.

They tell an agent which files are original sources, which it may generate, and how the project is organised.

How HanshGoyal/second_brain configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to HanshGoyal/second_brain. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/HanshGoyal/second_brain/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/HanshGoyal/second_brain

Made for: Claude Code.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/hanshgoyal/second_brain/claude-md/github.svg)](https://agentmods.dev/instructions/hanshgoyal/second_brain/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/hanshgoyal/second_brain/claude-md"><img src="https://agentmods.dev/badge/instructions/hanshgoyal/second_brain/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/hanshgoyal/second_brain/claude-md"><img src="https://agentmods.dev/badge/instructions/hanshgoyal/second_brain/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 880 This file is loaded in full into every session.

When invoked 880 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00880	$0.00880
Opus 5.5	$0.00352	$0.00352
Sonnet 5.5	$0.00176	$0.00176
Haiku 4.5	$0.00088	$0.00088

Measured 2mo ago against content hash 16781cd381fe, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

second_brain CLAUDE.md 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 2mo 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.

CLAUDE.md · 121 lines

How it starts

The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md - LLM Wiki Agent Guide

This file provides guidance to LLM agents working with this wiki.

Project Overview

This is a hybrid LLM Wiki combining:

Karpathy's LLM Wiki pattern - AI synthesizes and maintains knowledge
Stephen Kanegan's Obsidian structure - organized folders and templates

Core Philosophy

Raw sources in raw/ are immutable - never modify them
Wiki pages are AI-generated synthesis - LLM creates and maintains
Human role: Add sources, ask questions, think about meaning
LLM role: Do all the work - ingest, synthesize, cross-reference, maintain

Directory Structure

llm-wiki/
├── raw/                    # Your sources - ADD FILES HERE
├── wiki/
│   ├── index.md           # Catalog - check this first
│   ├── log.md             # Activity history
│   ├── daily/             # Session notes
│   ├── templates/         # Page templates
│   ├── sources/           # Source summaries
│   ├── entities/          # People, places, organizations
│   ├── concepts/          # Topics, ideas, theories
│   ├── analyses/         # Answers to questions
│   └── comparisons/       # Comparison tables
└── schemas/
    └── wiki-agent-guide.md  # Detailed instructions (READ THIS)

Key Workflows

1. INGEST - Adding Sources

User drops file in raw/
Read the source
Create source page in wiki/sources/
Extract/update entities in wiki/entities/
Extract/update concepts in wiki/concepts/
Update wiki/index.md
Append to wiki/log.md with format: ## [YYYY-MM-DD] ingest | Title
Create/update daily note in wiki/daily/

2. ANSWER - Responding to Questions

Read wiki/index.md to find relevant pages
Read those pages
Synthesize answer
File answer as new page in wiki/analyses/ (critical!)
Update index.md
Append to log.md: ## [YYYY-MM-DD] query | Question summary

3. DAILY - Session Notes

At end of every session:

Create wiki/daily/YYYY-MM-DD.md
Document: learnings, questions, wiki updates, ideas
Template in wiki/templates/daily-template.md

Read the full file on GitHub · 121 lines

Changes

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.

2mo ago First seen · 121 lines · 880 tokens per session scan A 16781cd381fe

Subscribe to this mod's changes

second_brain CLAUDE.md is an instructions file published in the GitHub repository HanshGoyal/second_brain (6 stars, last pushed 6mo ago), licensed MIT. It adds 880 tokens to every session, about $0.0035 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Memory and context Writing and docs

second_brain CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
second_brain CLAUDE.mdHanshGoyal/second_brain	Instructions file	6	6mo ago	MIT	A	880	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

second_brain: Instructions file for Claude Code