Skills are what MCP should have been 📝
Anthropic announced Agent Skills on October 16th, and I reckon this is one of those quiet releases that ends up mattering more than the flashy model drops.
A skill is a markdown file with YAML frontmatter. That's it. No server process. No JSON-RPC. No WebSocket connections. No Docker containers. A markdown file. And the clever bit is how it loads.
Level 1 is metadata. Name, description, trigger conditions. Costs you about 30 to 100 tokens and it's always in context. Level 2 is instructions. The actual "how to do the thing" content. Under 5,000 tokens. Only gets loaded when the model decides it's relevant to your task. Level 3 is resources. Referenced files, example code, whatever. Only pulled in when the instructions explicitly reference them.
So you've got a system where 100 skills can sit in your context at a cost of maybe 3,000 to 10,000 tokens total. The metadata layer alone. The model reads the names and descriptions, figures out which ones matter, and loads only what it needs.
