name.
An agent loads a skill’s full body only when its description looks relevant to the task at hand. The description is the trigger it routes on.
What’s in a skill
For exact field constraints, see Create a skill.
Create custom skills
Create a skill once, then reference it byname from any agent’s skills array.
How an agent uses a skill
An agent doesn’t read every attached skill up front. Each one is advertised to it byname and description in an <available_skills> section of the system prompt, with the body held back:
description relevant to the task, it calls a built-in load_skill tool with that name. The tool returns the full skill, and its body enters the conversation as instructions for the steps that follow.
- A mismatched name gets back the closest available names, so the agent can retry.
url_pattern, when set, is listed next to the description as a hint. It is not matched against the live page.
Write effective skills
- Make the
descriptiona trigger, not a summary. It is the only thing the agent sees before loading a skill, so phrase it as “use this when…” and name the situation precisely. Vague descriptions get loaded at the wrong time or not at all. - Keep the
bodyself-contained. The agent reads it cold, mid-task, so write a focused procedure (steps, formats, edge cases) rather than background prose. - Put always-on behavior in the agent’s
instructions. Reserve skills for procedures that only apply some of the time, so they stay out of context until they are relevant. - Compose small skills. Several narrow skills route better than one broad skill, because each
descriptioncan target a distinct situation.
Built-in skills
H maintains a catalog of computer-use skills under theh/ namespace. Attach them to any agent by name.
List them by filtering on the h/ prefix, or fetch one by name:
Endpoints
The list is paginated (
page, size) and returns an items / page / total envelope. Sort it with sort=created_at or sort=name (prefix - for descending), and filter with name (substring match) or search (matches name or description).