Skill Files

#075 0:26 Part of the Rysh video series

Define an agent once in a file -- name, model, and system prompt -- then spawn it anywhere.

Skill Files — 0:26 walkthrough

What you'll see

Launch rysh; create .rysh/agents/reviewer/SKILL.md with YAML frontmatter (name, description, model) and a prompt body.
cat .rysh/agents/reviewer/SKILL.md -- show the --- frontmatter then the body; no frontmatter means the whole file is the prompt and the name comes from the filename.
Double-Escape into rysh mode; ##agent spawn .rysh/agents/reviewer/SKILL.md.
##agent list confirms the agent was built entirely from the file.

Commands shown

rysh
mkdir -p .rysh/agents/reviewer
printf -- '---\\nname: code-reviewer\\ndescription: Reviews code for quality\\nmodel: claude-sonnet-4-20250514\\n---\\nYou are a code reviewer. Review code for quality, correctness, and adherence to best practices.\\n' > .rysh/agents/reviewer/SKILL.md
cat .rysh/agents/reviewer/SKILL.md
##agent spawn .rysh/agents/reviewer/SKILL.md
##agent list

Keys used

EnterEscape

Transcript

0:00Define an agent once in a file -- name, model, and system prompt -- then spawn it anywhere.

0:03Launch rysh. A skill file is just a markdown file with YAML frontmatter.

0:08Let's write one. The frontmatter sets name, description, and model; everything after it becomes the agent's system prompt.

0:16Cat the file to see the format: the YAML block between the dashes, then the prompt body. With no frontmatter, the whole file is the prompt and the name comes from the filename.

0:26Spawn straight from the file. Double-Escape into rysh mode, then point ##agent spawn at the SKILL.md path.

0:47Skill files turn agents into code you can commit and reuse.

Key takeaway

A skill file is markdown with optional YAML frontmatter (name/description/model) plus a system-prompt body, making agents reusable and version-controlled.