Heuristic
Turn a recurring AI workflow into a skill only when the trigger is clear
A reusable skill should remove repeated thinking, not create a new library you now have to search.
When it fits
- You repeatedly explain the same procedure to an AI tool or coding agent.
When to avoid it
- Do not encode unstable or one-off behavior as permanent skill instructions; maintenance cost can exceed the saved prompting.
Why it matters
Promote a repeated workflow into a skill when you can name the trigger, required inputs, steps or decision points, output and acceptance check. Keep project-specific facts in references rather than hard-coding them into the procedure. If you cannot say when the skill should fire, keep the workflow as an ordinary note until the pattern becomes clearer.
An example
A repeated 'review SAP mass-update file' workflow can become a skill with file checks, key-field rules and an output report, while customer-specific values stay in project references.
Check your result
A person who did not write the skill can tell when to invoke it and what acceptable output looks like.
Keep this limit in mind
- Do not encode unstable or one-off behavior as permanent skill instructions; maintenance cost can exceed the saved prompting.
Connected ideas
Use beforeAblate a skill before you trust it
Evidence and sources
AI Engineer skill guidance separates invocation, procedural steps and supporting references so a reusable skill need not inject all detail into every turn.
Skill formats vary by harness; the transferable idea is selective invocation and separation of procedure from reference.
Building Great Agent Skills: The Missing Manual · Trigger; structure; steps versus references