A Claude Code skill is a folder of instructions (a SKILL.md file) that Claude Code loads on demand to do one job well — write a cold email, build an ICP, audit an outbound engine, draft a LinkedIn post. A system prompt is the instruction block you paste at the top of any LLM chat to turn it into a specialist for the same task. The skills are built for Claude Code; the system prompts work in any LLM.
To install a skill, download the .md and drop it under your Claude Code skills directory (or a project .claude/skills folder), then invoke it by name. To use a system prompt, paste the file contents as the system or instructions message in ChatGPT, Claude, Gemini or whatever you run. Every file below is the same asset we use to run client outbound.