A skill document is a Markdown file with YAML frontmatter — name, description, version, platforms, metadata — following the 📝agentskills.io standard, the unit of procedural knowledge 📝Hermes Agent generates and refines.
The frontmatter declares identity, version metadata, and the supported platforms or model families the skill applies to. The body is procedural prose: how to do the task, the pitfalls that recur, and the verification steps that confirm completion. The skill is human-readable, auditable, and version-controllable like any other Markdown file in a repository.
Hermes generates a skill document autonomously after complex tasks — typically five or more tool calls, the heuristic threshold for "worth documenting" — and patches the document in place during later runs when reality contradicts or extends what's written. Skill documents can also be hand-authored, installed from the agentskills.io marketplace, or generated by other agentskills.io-compliant runtimes; the format does not privilege any one source.
The skill document is the unit of compounding intelligence in the 📝closed learning loop — distinct from a prompt template (static text), a chain-of-thought trace (per-run reasoning), or a fine-tuning sample (training data). It carries the same structural role for an agent that an SOP carries for a team: durable procedural knowledge separated from the moment of execution, refined over many runs.