What is Skrills?

Skrills validates, analyzes, and synchronizes skills across Claude Code, Codex CLI, GitHub Copilot CLI, and Cursor. It resolves compatibility issues between the four environments and provides tools to manage context usage effectively.

The Problem

Claude Code, Codex CLI, GitHub Copilot CLI, and Cursor all use markdown-based “skills,” but they enforce different requirements. Claude Code has a permissive structure, Codex CLI and Copilot CLI demand strict YAML frontmatter, and Cursor uses .mdc rule files with mode-specific fields like globs and alwaysApply. Skills written for one tool often fail in the others.

Skrills solves this friction by validating frontmatter and schema compliance, syncing configurations and skills between all four CLIs, and analyzing token usage to prevent context overflow.

Core Features

Validate Skills

The validation engine checks compliance with Codex’s strict requirements. You can automatically fix missing frontmatter by running:

skrills validate --target codex --autofix

Analyze Token Usage

To prevent context window exhaustion, Skrills identifies heavy skills that might need optimization:

skrills analyze --min-tokens 1000 --suggestions

Sync Between Tools

Skrills mirrors your configuration between environments, verifying your tools are available everywhere:

skrills sync-from-claude    # Claude as source of truth
skrills sync-from-cursor    # Cursor as source of truth
skrills sync                # Bidirectional sync

Run as MCP Server

You can expose these capabilities directly to your AI assistant by running Skrills as an MCP server, or launch the browser dashboard:

skrills serve                    # MCP server over stdio
skrills serve --http --open      # Browser dashboard with REST API

HTML Portal

Skrills ships with a self-contained HTML portal (skrills-portal.html) that provides an interactive browser-based interface for exploring skills, validating content, analyzing tokens, converting between CLI formats, and browsing the full MCP tool and CLI command reference. The portal works offline on file:// protocol and can be uploaded into AI application portals.

Quick Start

1. Install:

   curl -LsSf https://raw.githubusercontent.com/athola/skrills/HEAD/scripts/install.sh | sh
   

2. Validate:

   skrills validate
   

3. Sync:

   skrills sync-from-claude
   

Key Concepts

Skills

Skills are SKILL.md files containing instructions and metadata. Skrills scans for these files in ~/.claude/skills, ~/.codex/skills, ~/.copilot/skills, ~/.cursor/rules/, and the universal ~/.agent/skills directory.

MCP (Model Context Protocol)

Skrills implements the Model Context Protocol, allowing assistants to invoke its tools (validation, analysis, sync) directly during a session.

Validation Targets

Validation rules depend on the target. Claude Code is permissive and accepts any markdown with optional frontmatter. Codex CLI and Copilot CLI are strict, requiring name and description fields in the YAML frontmatter. Cursor uses .mdc rule files where the description field is required and mode is derived from globs or alwaysApply fields.

Architecture

Skrills is a Rust workspace:

Next Steps

• Installation Guide
• Sync Guide
• MCP Token Optimization
• FAQ