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cerebellum: Instructions file for Claude Code

CLAUDE.md

cerebellum CLAUDE.md is an instructions file for Claude Code from jj-valentine/cerebellum. It costs 459 tokens per session, scanned A, original, MIT.

Project instructions for Cerebellum, a personal knowledge system that stores thoughts in a database and lets AI tools search them through one MCP server. They cover its technology, commands, key files, and environment settings.

In plain words
What is it for?
Use them when developing Cerebellum, running its CLI or MCP server, configuring Supabase and OpenRouter, or changing its storage and retrieval pipeline.
Why use it?
They explain how to build, run, configure, capture, and search information without guessing the project's setup.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: reads .claude/ paths; mentions Claude Code.

This is jj-valentine/cerebellum's own configuration. It tells Claude Code how to work on cerebellum itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything cerebellum configures →

Not installable: its command points at a path on the author’s own machine, so it runs nowhere else. The line is /Users/james/dev/new/cerebellum/dist/mcp/server.js.

not rated 37repo 5mo ago A scan 459 tokens original MIT
View source ↗ jj-valentine/cerebellum james-valentine.com
Reuse

Borrowing it

Nothing to install: this file belongs to jj-valentine/cerebellum. 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/jj-valentine/cerebellum/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/jj-valentine/cerebellum

Made for: Claude Code.

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Per session 459 This file is loaded in full into every session.
When invoked 459 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00459 $0.00459
Opus 5.5 $0.00184 $0.00184
Sonnet 5.5 $0.00092 $0.00092
Haiku 4.5 $0.00046 $0.00046

Measured 2mo ago against content hash 7bf15db4f73b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

cerebellum 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 · 58 lines

What it actually says

Cerebellum

Personal agent-readable second brain. Postgres + pgvector + MCP.

What this is

A knowledge capture + retrieval system. Thoughts go in via CLI or MCP. Every AI tool (Claude, ChatGPT, Cursor, VS Code) can query it via a single MCP server.

Stack

  • Database: Supabase (Postgres + pgvector)
  • Embeddings: OpenRouter → openai/text-embedding-3-small
  • Classifier: OpenRouter → openai/gpt-4o-mini
  • MCP server: src/mcp/server.ts (Node.js, @modelcontextprotocol/sdk)
  • CLI: src/cli/index.ts

Commands

npm run build          # compile TypeScript
npm run mcp            # start MCP server
npm run cli -- "text"  # capture a thought
npm run cli -- search "query"  # search thoughts

Key files

File Purpose
schema/schema.sql Postgres schema — run once in Supabase SQL editor
src/config.ts All env var loading + validation
src/capture.ts Core pipeline: embed → classify → store
src/mcp/server.ts MCP server entry point

Environment

Copy .env.example → .env and fill in:

  • SUPABASE_URL
  • SUPABASE_SERVICE_KEY (service role, not anon)
  • OPENROUTER_API_KEY

MCP setup (Claude Code)

After npm run build:

claude mcp add --transport stdio --scope user cerebellum -- node /Users/james/dev/new/cerebellum/dist/mcp/server.js

This stores the config in ~/.claude.json and makes the server available globally across all Claude Code sessions.

Dev workflow

  • Branch: feat/<scope>, fix/<scope>, etc.
  • Commits: conventional (feat(mcp): add semantic_search tool)
  • Plans: docs/plans/
  • Never commit .env
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.

  1. 2mo ago First seen · 58 lines · 459 tokens per session scan A 7bf15db4f73b

Subscribe to this mod's changes

cerebellum CLAUDE.md is an instructions file published in the GitHub repository jj-valentine/cerebellum (37 stars, last pushed 5mo ago), licensed MIT. It adds 459 tokens to every session, about $0.0018 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 2026-08-30.

DatabasesMemory and contextai-agentsmcppgvectorsecond-brainsemantic-search
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