Ontomics
🦀 🏠 🍎 🐧 - Semantic code index that extracts domain concepts, naming conventions, and
What is Ontomics?
Ontomics is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to 🦀 🏠 🍎 🐧 - semantic code index that extracts domain concepts, naming conventions, and
🦀 🏠 🍎 🐧 - Semantic code index that extracts domain concepts, naming conventions, and
This server falls under the Coding Agents and Developer Tools categories on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- MCP protocol support
Use Cases
Maintainer
Works with
Installation
NPM
npx -y @ontomics/ontomicsManual Installation
npx -y @ontomics/ontomicsConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Ontomics
Ontomics is a semantic code indexer written in Rust that analyses your repository and builds a rich domain knowledge graph — extracting concepts, naming conventions, vocabulary health, logic similarity clusters, and type flows — and exposes all of this through an MCP server so AI coding agents can understand your codebase's domain language at a glance. It supports Python, TypeScript, JavaScript, and Rust out of the box, stores its index in a local .ontomics/index.db SQLite file, and is distributed as a prebuilt binary available via npm, Homebrew, or a shell installer. Teams can check a .mcp.json into their repo so every developer's coding agent automatically gets shared ontomics context.
Prerequisites
- A git repository (ontomics requires a .git/ directory and will refuse to index home or root directories)
- Node.js 18+ (to use the npm/npx distribution) OR Homebrew on macOS OR the shell installer for direct binary installation
- An MCP client such as Claude Code, Cursor, or any agent supporting the Model Context Protocol
- One of the supported languages in your codebase: Python, TypeScript, JavaScript, or Rust
Install the ontomics binary
Choose the installation method that suits your environment. npm/npx is the easiest cross-platform option; Homebrew is recommended on macOS for a persistent global install.
# Via npm (global install)
npm install -g @ontomics/ontomics
# Via Homebrew (macOS)
brew install EtienneChollet/tap/ontomics
# Via shell installer (macOS/Linux)
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/EtienneChollet/ontomics/releases/latest/download/ontomics-installer.sh | shRegister ontomics with your MCP client
Add ontomics as an MCP server in your client. For Claude Code, use the mcp add command. For other clients, add the JSON configuration block manually.
# Claude Code
claude mcp add -s user ontomics -- ontomics
# Codex
codex mcp add ontomics -- ontomicsNavigate to your repository and run the initial index
From your project root (which must contain a .git directory), trigger ontomics to build the index. The index is stored in .ontomics/index.db.
cd /path/to/your/project
ontomicsShare the configuration with your team (optional)
Add a .mcp.json file to the repository root so all team members' MCP clients automatically pick up ontomics with the correct settings pointing to the repo.
{
"mcpServers": {
"ontomics": {
"command": "npx",
"args": ["-y", "@ontomics/ontomics", "--repo", "."]
}
}
}Access the briefing resource in your AI client
The ontomics://briefing MCP resource provides a ready-made conventions summary and vocabulary warnings that you can inject into your AI agent's context before starting a coding session.
Ontomics Examples
Client configuration (Claude Desktop / stdio)
Add this to claude_desktop_config.json to run ontomics as a local MCP server using npx.
{
"mcpServers": {
"ontomics": {
"command": "npx",
"args": ["-y", "@ontomics/ontomics"]
}
}
}Prompts to try
Once connected, ask your AI assistant to use ontomics to understand your codebase.
- "Read the ontomics://briefing resource and summarise the naming conventions in this repo."
- "What are the core domain concepts extracted from this codebase?"
- "Find functions with logic similar to the parseUserInput function."
- "Show me the vocabulary health report — are there any inconsistently named symbols?"
- "Give me an overview of the src/services directory based on the ontomics index."Troubleshooting Ontomics
ontomics refuses to index with an error about the directory
ontomics requires a .git directory and will refuse to run in home (~), root (/), or temp directories. Run it from within an actual git repository. If you have a legitimate need to index a non-standard location, pass the --force flag.
No symbols or concepts appear after indexing
Confirm your codebase contains files in a supported language (Python .py, TypeScript .ts, JavaScript .js, or Rust .rs). ontomics auto-detects languages from file extensions; other languages are not yet indexed.
The npx command is not found or fails to run
Ensure Node.js 18+ is installed and npx is in your PATH. Alternatively, install the binary directly via Homebrew or the shell installer and use the 'ontomics' command directly instead of npx.
Frequently Asked Questions about Ontomics
What is Ontomics?
Ontomics is a Model Context Protocol (MCP) server that 🦀 🏠 🍎 🐧 - semantic code index that extracts domain concepts, naming conventions, and It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Ontomics?
Install via npm with the command: npx -y @ontomics/ontomics. Then add the server configuration to your AI client's JSON config file (e.g., claude_desktop_config.json or .cursor/mcp.json).
Which AI clients work with Ontomics?
Ontomics works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Ontomics free to use?
Yes, Ontomics is open source and available under the MIT License license. You can use it freely in both personal and commercial projects.
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Browse More Coding Agents MCP Servers
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Set Up Ontomics in Your Editor
Choose your AI client for step-by-step setup instructions.
Quick Config Preview
Add this to your claude_desktop_config.json or .cursor/mcp.json
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