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<img src="assets/logo.png" width="280" alt="claude-mega-brain logo" />
# claude-mega-brain
*Loads the knowledge. Skips the search.*
[](https://github.com/guhcostan/claude-mega-brain/actions)
[](https://github.com/guhcostan/claude-mega-brain)
[](https://github.com/guhcostan/claude-mega-brain/releases)
[](LICENSE)
[](https://github.com/anthropics/claude-code)
**100% accuracy · 0 tool calls · −66% tokens vs Obsidian+MCP**
Real agentic sessions. [Benchmark →](benchmarks/results/agentic-obsidian-vs-mega-brain.md)
</div>
---
## Install
```
/plugin marketplace add guhcostan/claude-mega-brain
/plugin install mega-brain@mega-brain
```
Then in any project:
```
/mega-brain:init
```
Start a new session — the knowledge base loads automatically.
---
## The problem
Without claude-mega-brain, Claude guesses from training data:
```
User: What column stores the order total?
Claude (no context): Typically total_amount (DECIMAL) or amount (FLOAT)...
# Wrong — this project uses total_cents (INT64)
```
With claude-mega-brain, the exact schema is injected at `SessionStart`:
```
<mega-brain>
Knowledge: 4 documented concepts found in project
docs/orders.md [BigQuery Table] — total_cents INT64, status STRING(pending/confirmed/shipped/done)
docs/customers.md [BigQuery Table] — customer_id STRING, email STRING, country STRING
docs/wau.md [Metric] — COUNT(DISTINCT user_id) WHERE session_date >= CURRENT_DATE-7
docs/net_revenue.md [Metric] — SUM(total_cents - refund_cents)/100 WHERE status='done'
</mega-brain>
User: What column stores the order total?
Claude: total_cents (INT64) — from docs/orders.md
# Correct. 0 tool calls. First turn.
```
---
## Benchmark
10 questions with project-specific values unknowable from training data.
Real agentic sessions — not simulated.
| metric | no context | Obsidian+MCP | CLAUDE.md (raw files) | **claude-mega-brain** |
|---|--:|--:|--:|--:|
| accuracy (no tools) | 50% | 13% | 100% | **100%** |
| accuracy (agentic) | 100%† | 100%† | 100% | **100%** |
| tool calls avg | 1.1 | 0.9 | 0.1 | **0** |
| tokens avg | 61,521 | 49,186 | 20,624 | **16,547** |
| latency avg ms | 10,267 | 10,986 | 5,494 | **4,384** |
† raw and Obsidian+MCP reach 100% agentic accuracy by using tool calls to explore the project — spending 3–4× more tokens and time. Without tools, they drop to 50% and 13%.
CLAUDE.md (raw files) matches mega-brain on accuracy but uses 25% more tokens and is 25% slower. mega-brain's compressed OKF index is smaller and faster — the gap widens as knowledge bases grow.
[Full results](benchmarks/results/agentic-obsidian-vs-mega-brain.md) · [Reproduce](benchmarks/)
---
## How it works
At `SessionStart`, a hook scans the entire project for any `.md` file with `type:` in its YAML frontmatter and injects a compact index:
```
<mega-brain>
Knowledge: 8 documented concepts found in project
Recent (log.md):
2026-06-29 — added customers table
index.md [Index] — Central reference for all sales data
docs/orders.md [BigQuery Table] — One row per completed order
docs/customers.md [BigQuery Table] — Customer profiles
docs/wau.md [Metric] — Weekly active users
...
</mega-brain>
```
No dedicated folder needed — documents can live anywhere in the project. When Claude reads an OKF file, linked concepts surface automatically via `PostToolUse`.
**Zero overhead when not in use** — if no documented concepts are found, the hook exits in <5ms.
---
## How it compares
| tool | auto-inject | schema enforcement | tool calls to answer | accuracy (no tools) |
|------|-------------|-------------------|---------------------|---------------------|
| **claude-mega-brain** | ✓ SessionStart hook | required (`type:`) | **0** | **100%** |
| CLAUDE.md + additionalDirectories | manual setup | none | 0 | 100%* |
| Obsidian + MCP | ✗ manual | none | 1–3 | 13% |
| Notion | ✗ manual | proprietary | N/A | — |
| Logseq | ✗ plugin-based | none | N/A | — |
| mem.ai | ✗ none | none | N/A | — |
\* CLAUDE.md matches mega-brain accuracy but uses 25% more tokens and is 25% slower — raw file dump vs compressed structured index.
---
## OKF Format
Any `.md` file in the project with `type:` in its YAML frontmatter is automatically picked up. No dedicated folder needed.
```markdown
---
type: BigQuery Table
title: Orders
description: One row per completed customer order.
resource: https://console.cloud.google.com/bigquery?p=acme&d=sales&t=orders
tags: [sales, revenue]
timestamp: 2026-06-29T00:00:00Z
---
# Schema
| Column | Type | Description |
|-------------|-----------|--------------------------|
| order_id | STRING | Globally unique order ID |
| customer_id | STRING | FK → customers |
| total_cents | INT64 | Order total in cents |
| status | STRING | pending/confirmed/shipped/done |
# Joins
Joined with [customers](customers.md) on `customer_id`.
```
### Reserved files
| File | Purpose |
|------|---------|
| `index.md` (with `type: Index`) | Knowledge map — Claude reads this first |
| `log.md` (with `type: Log`) | Append-only changelog — last 3 entries injected at session start |
### Common types
`BigQuery Table` · `BigQuery Dataset` · `Table` · `Metric` · `API` · `Runbook` · `Concept` · `Service` · `Pipeline`
Types are freeform — add your own.
---
## Usage
### Start from scratch
```
/mega-brain:init
```
Creates `index.md` and `log.md` anywhere you want. Start a new session — context injects automatically.
### Migrate existing docs
```
/mega-brain:migrate
```
Scans `openapi.yaml`, `schema.prisma`, `schema.sql`, `docs/`, `README` sections and adds `type:` frontmatter to generate OKF concepts.
### Add a single concept
```
/mega-brain:ingest
```
Document a specific table, metric, API, or service. Saves the file wherever makes sense for your project structure.
---
## Installation
### Claude Code
```
/plugin marketplace add guhcostan/claude-mega-brain
/plugin install mega-brain@mega-brain
```
### Local development
```bash
claude plugin install /path/to/claude-mega-brain
```
---
## Config (`.mega-brain.json`)
Optional per-project overrides:
```json
{
"dir": "knowledge",
"maxConcepts": 100,
"priorityTypes": ["Metric", "BigQuery Table"]
}
```
| Field | Default | Description |
|-------|---------|-------------|
| `dir` | *(none)* | Limit scanning to this subdirectory (relative to project root). When unset, the entire project is scanned. |
| `maxConcepts` | `60` | Max concepts in injected index |
| `priorityTypes` | `[]` | Types shown at top of index |
| `exclude` | `[]` | Additional dirs to skip when scanning |
---
## FAQ
**Does it slow down every session?**
No. If no OKF directory exists, the hook exits in <5ms with no context injected.
**Can I use it with an existing wiki or docs folder?**
Add `type:` YAML frontmatter to any Markdown file and drop it in your OKF dir. Done.
**What if I have 500 concepts?**
Set `maxConcepts` in `.mega-brain.json`. The index stays compact; `index.md` holds the full map.
---
## References
- [Open Knowledge Format — Google Cloud](https://cloud.google.com/blog/products/data-analytics/how-the-open-knowledge-format-can-improve-data-sharing)
- [LLM Wiki pattern — Andrej Karpathy](https://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f)
- [Mega Brain — Thiago Finch](https://www.instagram.com/reel/DZI-ys4h29A/) — the meme this plugin is named after
---
## Star History
<a href="https://www.star-history.com/?type=date&repos=guhcostan%2Fclaude-mega-brain">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/chart?repos=guhcostan/claude-mega-brain&type=date&theme=dark&legend=top-left" />
<source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/chart?repos=guhcostan/claude-mega-brain&type=date&legend=top-left" />
<img alt="Star History Chart" src="https://api.star-history.com/chart?repos=guhcostan/claude-mega-brain&type=date&legend=top-left" />
</picture>
</a>
---
## License
[MIT](LICENSE) — The shortest license that works.