cortex — Claude Code MCP server: what it does, how to install
Maps project symbols, code relationships, and repo rules locally so coding agents find relevant context without scanning every file.
claude mcp add cortex -- npx -y @danielblomma/cortex-mcpWhat cortex does
The tool scans your codebase directly on your machine, cataloging symbol definitions, dependencies, and project conventions. Instead of guessing filenames or reading broad directory trees, the assistant queries this local map to pull exact call paths and dependency graphs.
Under the hood, it pairs background file watchers and Git hooks with diagnostic utilities like cortex impact for blast radius checks and cortex conventions for rule verification. An MCP interface is available, but assistants can also execute the CLI commands directly.
Running this indexer requires Git alongside Node.js 20.9+. Without that runtime baseline, index generation fails. Background bootstrap mode is limited to macOS, Linux, and WSL, meaning standard Windows installations must run indexing in the foreground.
What it helps with
- estimate the blast radius before refactoring sensitive modules
- find symbol definitions and file relationships without broad scans
- verify staged diffs against repository rules and coding patterns
- keep indexing caches synchronized after Git branch switches
Example prompts for the agent
- Run cortex search to locate where auth tokens are parsed
- Check the blast radius of modifying payments.ts using cortex impact
- Review candidate changes with cortex review --diff before staging
How to install cortex
Platform CLI
claude mcp add cortex -- npx -y @danielblomma/cortex-mcpPlatform CLI
codex mcp add cortex -- npx -y @danielblomma/cortex-mcpConfig file
{
"mcpServers": {
"cortex": {
"command": "npx",
"args": [
"-y",
"@danielblomma/cortex-mcp"
]
}
}
}Config file
{
"servers": {
"cortex": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@danielblomma/cortex-mcp"
]
}
}
}Platform CLI
gemini mcp add cortex npx -y @danielblomma/cortex-mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about cortex
How to install cortex in Claude Code?
Run claude mcp add cortex -- npx -y @danielblomma/cortex-mcp in your terminal. Next, navigate to your project directory and execute cortex init --bootstrap.
What does cortex do?
It constructs a local dependency map and semantic index of your repository. This lets AI agents retrieve relevant symbols, rules, and blast radius reports directly.
What prerequisites does cortex require?
You need Git and Node.js version 20.9+ installed on your system. All index operations process locally without sending code to third-party endpoints.
