Cortex — Contextual AI Coding Skills for Claude Code

🚀 Install once and stop re-explaining how you write code. Claude picks the right conventions for whatever you've opened — TypeScript, Python, React, Next.js, NestJS, .NET, testing, docs.

✨ How It Works

No slash commands to memorize. Each skill describes when it should fire, and Claude Code pulls in whichever ones match what you're doing:

• Open a .tsx file → react and typescript kick in.
• Edit a NestJS controller → nestjs brings the module/DI/guard/DTO rules.
• Ask for tests → testing picks the right unit/integration/E2E approach.
• Draft API docs → documentation handles the voice and OpenAPI structure.
• Wrap up a ticket → jira-report-comment writes the Jira update from your commits.

Install it once and your conventions follow you around. Nothing to paste at the start of a session, nothing to repeat on a fresh repo. (You can still call any skill yourself with /cortex:<skill> if you'd rather.)

📚 Skill Library

Languages

• /cortex:typescript — Strict tsconfig, branded types, advanced generics, discriminated unions, tRPC, monorepos.
• /cortex:javascript — Modern ES2023+, Promise patterns, ESM/CJS, Web Workers, Node.js best practices.
• /cortex:python — Python 3.11+, type hints with mypy, async/await, pytest fixtures, dataclasses, Poetry.
• /cortex:csharp — C# 12, records, primary constructors, pattern matching, async, CQRS with MediatR.

Frameworks

• /cortex:react — React 18/19, hooks, Server Components, Suspense, performance memoization, form actions.
• /cortex:nextjs — Next.js 14+ App Router, Server Actions, caching, Metadata API, Vercel deployment.
• /cortex:nestjs — Modules, DI, controllers/services, DTO validation, guards, JWT auth, TypeORM/Prisma.
• /cortex:dotnet-core — .NET 8 clean architecture, CQRS, minimal APIs, EF Core, AOT, cloud-native patterns.

Engineering Workflows

• /cortex:testing — Unit, integration, E2E, performance, and security testing patterns plus coverage analysis.
• /cortex:documentation — Microsoft-style technical writing, JSDoc/Google/NumPy docstrings, OpenAPI, doc portals.
• /cortex:spec-mining — Reverse-engineer legacy or undocumented systems into EARS-format requirements.
• /cortex:legacy-modernization — Strangler fig, branch by abstraction, characterization tests, framework upgrades.
• /cortex:jira-report-comment — Turn git commits into a business-friendly Jira implementation report.
• /cortex:humanize-text — Strip "AI fingerprints" from text so writing reads natural.

💡 Why Cortex

Most AI assistants will happily generate something. Getting them to write code your way — your conventions, your architecture, your trade-offs — usually means re-explaining yourself every session or letting CLAUDE.md balloon out of control.

Cortex is what I built after I got tired of doing that. A stack of personal preferences, project scars, and team rules I've collected over the years, packaged so Claude can reach for the right one on its own. Fork it, gut half of it, swap mine for yours — that's kind of the point.

📦 Installation

Pick the path for your AI coding assistant:

Claude Code Plugin

claude plugin marketplace add alexander-danilenko/cortex-ai-skills
claude plugin install cortex@alexander-danilenko

Done. Claude will pull in the right skills as you work and keep them updated.

Recommended companion Claude Code plugins

• Official Claude Code plugins:

  CLAUDE_PLUGINS=(
    "claude-code-setup"
    "claude-md-management"
    "code-review"
    "code-simplifier"
    "context7"
    "feature-dev"
    "skill-creator"
    "csharp-lsp"
    "rust-analyzer-lsp"
    "typescript-lsp"
  ) && for plugin in "${CLAUDE_PLUGINS[@]}"; do claude plugin install "${plugin}@claude-plugins-official"; done

• EveryInc/compound-engineering-plugin

• obra/superpowers

Codex, Cursor, OpenCode, Pi, Gemini CLI, and other AI agents

Cortex installs into any agent that npx skills supports — Codex, Cursor, OpenCode, Pi, Gemini CLI, and more. Grab your --agent identifier from the supported agents list.

Install all skills (swap cursor for your agent's identifier):

npx skills add alexander-danilenko/cortex-ai-skills --skill '*' --agent cursor

Install a single skill:

npx skills add alexander-danilenko/cortex-ai-skills --skill python --agent cursor

List available skills:

npx skills add alexander-danilenko/cortex-ai-skills --list

To update, re-run the add command. Unlike the Claude Code plugin path, npx skills won't pull updates on its own.

🛠️ Development

To load the plugin from a local clone (session-only):

claude --plugin-dir /path/to/cloned/repo

To make it persistent, register the repo as a local marketplace in ~/.claude/settings.json:

{
  "extraKnownMarketplaces": {
    "local": {
      "source": {
        "source": "directory",
        "path": "/path/to/cloned/repo"
      }
    }
  }
}

Then install once:

claude plugin install cortex@local

After pulling new changes, update with:

claude plugin update cortex@local

🙏 Credits

Jeffallan/claude-skills inspired me to start this project.

🤝 Contributing

These skills reflect a personal workflow — fork freely and adapt them to yours.

When adding or updating skills, use the skill-creator plugin so new skills match the expected format and conventions.

License