dev-brain-mcp

Your AI agent's persistent brain. Coding standards that never get forgotten, stack detection, and project memory that survives across conversations.

Inspired by ponytail, codebase-memory-mcp, and Graft.

The Problem

AI coding agents forget your rules in long conversations. Skills and instructions get truncated from the context window after many iterations. This MCP server solves that by:

1. Embedding rules in tool descriptions — tool descriptions live in the system prompt and NEVER get truncated

2. Detecting your stack automatically — no need to tell the agent "this is a React + RTK project" every time

3. Persistent project memory — notes, architectural decisions, and conventions survive across conversations

Related MCP server: dev-kit-mcp-server

Install

git clone https://github.com/YOUR_USERNAME/dev-brain-mcp.git
cd dev-brain-mcp
npm install

Setup in Antigravity 2.0

Global Configuration (recommended)

Go to Settings → MCP Servers and add:

{
  "mcpServers": {
    "dev-brain": {
      "command": "node",
      "args": ["C:/Users/david/Documents/dev-brain-mcp/server.js"]
    }
  }
}

⚠️ Update the path to wherever you cloned this repo.

Per-Project Configuration

Create .agents/mcp.json in your project root:

{
  "mcpServers": {
    "dev-brain": {
      "command": "node",
      "args": ["C:/path/to/dev-brain-mcp/server.js"]
    }
  }
}

Other Agents (Claude Code, Cursor, etc.)

Add to your MCP config:

{
  "mcpServers": {
    "dev-brain": {
      "command": "node",
      "args": ["/path/to/dev-brain-mcp/server.js"]
    }
  }
}

Tools

Why It Works

Skills (ponytail, RTK rules):
  → Instructions read into conversation context
  → Get TRUNCATED after ~30 iterations
  → Agent forgets them completely ❌

MCP Tool Descriptions:
  → Live in the system prompt alongside tool definitions
  → NEVER get truncated, no matter how long the conversation
  → Agent always sees them ✅

Persistent Memory (projects.json):
  → Stored on disk, survives across conversations
  → Agent retrieves context at start of each session
  → No re-exploration needed ✅

Adding Your Own Rules

Edit lib/rules.js:

• Universal rules: Add to UNIVERSAL_RULES.principles

• Stack-specific rules: Add a new key to CONDITIONAL_RULES

• Validation checks: Add patterns to validateCode()

License

MIT