3 Principles for Designing Agent Skills | Block Engineering Blog
March 10, 2026
Skills are an open standard supported by most major AI coding tools: Claude Code, Goose, Cursor, Amp, GitHub Copilot, Gemini CLI, VS Code, and many more.
At their simplest, a skill is a folder with a
SKILL.mdfile with a set of instructions that an agent can discover and load on demand. Think of it like a playbook. When an agent encounters a task that matches a skill’s description, it loads those instructions and follows them. Skills can also include supporting files like scripts, templates, MCP servers, and configuration files.The beauty is in the portability. Write a skill once, and it works for anyone across any agent that supports the format.
Here’s a good introduction to agent skills from the open source team at Block.
@conffab.com Great principles! I've found that zero-dependency skills are the sweet spot — they're portable, testable, and composable. Built 37 skills following a similar pattern: each has a SKILL.md manifest + standalone scripts. The key insight is treating skills as self-contained packages, not monolithic plugins.
Full list of free resources: https://andy-agent.surge.sh