What is second-brain CLAUDE.md?

Repository instructions for a personal wiki, or “second brain,” built from captured Markdown files. They explain separate folders for raw material, edited notes, generated documents, and the databases used for links and semantic search.

Use them when ingesting material, editing linked notes, generating briefs or other documents, rebuilding indexes, or searching the wiki.

They keep original captures safe while making it clear where notes, outputs, links, and search data belong.

How slowww-ai/second-brain configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to slowww-ai/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/slowww-ai/second-brain/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/slowww-ai/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/slowww-ai/second-brain/claude-md/github.svg)](https://agentmods.dev/instructions/slowww-ai/second-brain/claude-md)

Your own site

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

Per session 2,176 This file is loaded in full into every session.

When invoked 2,176 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	$0.02176	$0.02176
Opus 5.5	$0.00870	$0.00870
Sonnet 5.5	$0.00435	$0.00435
Haiku 4.5	$0.00218	$0.00218

Measured 1mo ago against content hash 98c754fb45dc, 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 1mo 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 · 139 lines

How it starts

The opening of the file, as written. The whole thing — 139 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Second Brain

A personal wiki built from raw captured markdown. Claude Code helps ingest, link, index, and synthesize.

Folder layout

wiki/raw/ — append-only dumps. Never edit or delete files here. Anything captured goes here first: clipped articles, meeting notes, transcripts, half-formed thoughts.
wiki/notes/ — the distilled wiki. Interlinked markdown notes derived from raw/. Safe to edit and rewrite.
wiki/outputs/ — generated deliverables (briefs, memos, docs, decks). Disposable.
scripts/ — Python helpers (ingest.py, reindex.py, search.py, yt_capture.py, dashboard.py).
wiki/lancedb/ — LanceDB vector store (table notes) holding Gemini embeddings. Used for semantic search.
wiki/index.db — SQLite side-table for links, ingested ledger, and note_meta (mtime tracking).
.claude/skills/_shared/ — production frameworks (templates / rubrics / playbooks that content skills apply when generating, e.g. the SNS hook playbook viral-hooks.md). Kept out of wiki/notes/ on purpose so they never pollute semantic search; skills reference them by path.
templates/ — Obsidian note template (note.md) with the frontmatter contract pre-filled.

Storage split

The index is deliberately split across two stores. Vectors live in LanceDB (wiki/lancedb/) for on-disk ANN search without loading every embedding into memory. Graph and ledger metadata lives in SQLite (wiki/index.db): links (wikilink edges, rebuilt every reindex), ingested (raw-file ledger keyed by filename, with content hash + produced notes), and note_meta (per-note mtime for incremental reindex). When changing the schema in one store, check whether the other needs a matching change.

Embeddings & search

Semantic search uses the Gemini gemini-embedding-2-preview model via google-genai, stored in LanceDB for on-disk vector search (no loading all embeddings into memory). scripts/reindex.py only re-embeds notes whose mtime changed.

Read the full file on GitHub · 139 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.

1mo ago Changed · +1 lines · +185 tokens per session 98c754fb45dc
2mo ago First seen · 138 lines · 1,991 tokens per session scan A b63e5c627bd5

Subscribe to this mod's changes

second-brain CLAUDE.md is an instructions file published in the GitHub repository slowww-ai/second-brain (10 stars, last pushed 1mo ago), licensed MIT. It adds 2,176 tokens to every session, about $0.0087 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

second-brain CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
second-brain CLAUDE.mdslowww-ai/second-brain	Instructions file	10	1mo ago	MIT	A	2,176	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