Skill Creator
A skill is a directory with a SKILL.md file (YAML frontmatter + markdown instructions). At startup the agent reads only each skill's name and description into the system prompt; the full file loads on demand when a task matches. The agent follows the Agent Skills standard and extends it with Python-backed skills.
| Kind | What it is | When to use |
|---|---|---|
| markdown | SKILL.md plus optional scripts, references, and assets | Workflows, CLI recipes, domain knowledge, multi-step instructions |
| python | A markdown skill that also ships a Python package installed into the agent's persistent Python kernel | Capabilities that are naturally one Python call: API wrappers, fetchers, converters, computations |
Before writing a Python-backed skill, read references/python-skills.md for the package contract.
Creating a Skill
- Pick the kind. Default to markdown. Go Python only when the agent should call the capability (
await my_skill(...)) instead of following instructions. - Pick the location. Ask the user when it is not obvious from context:
- Project skill, shared via the repo:
.devo/skills/<name>/(or.agents/skills/<name>/) - Personal global skill:
~/.devo/skills/<name>/ - Shipped with a plugin: the plugin's
skills/directory
- Project skill, shared via the repo:
- Scaffold and write the directory using the layout and frontmatter rules below.
- Verify the skill loads (see Verification).
On a name collision the first skill found wins. Precedence: explicit --skill paths and skills settings entries, then project, then global, then plugin, then built-in skills.
Layout
my-skill/ ├── SKILL.md # Required: frontmatter + instructions ├── scripts/ # Optional helper scripts the instructions reference ├── references/ # Optional detailed docs, loaded only when needed └── assets/ # Optional templates and data files
Everything except SKILL.md is freeform. Reference files with paths relative to the skill directory; the agent resolves them against the directory containing SKILL.md.
Frontmatter
markdown--- name: my-skill description: What this skill does and when to use it. Be specific. ---
| Field | Required | Rules |
|---|---|---|
name | Yes | Max 64 chars. Lowercase a-z, 0-9, hyphens. No leading/trailing/consecutive hyphens. Must match the parent directory name. |
description | Yes | Max 1024 chars. A skill with a missing or empty description is silently not loaded. |
disable-model-invocation | No | true hides the skill from the system prompt; only explicit /skill:<name> invokes it. |
license | No | License name or reference to a bundled file. |
compatibility | No | Max 500 chars. Environment requirements. |
metadata | No | Arbitrary key-value mapping. |
allowed-tools | No | Space-delimited pre-approved tools (experimental). |
Unknown fields are ignored. Name violations produce warnings but the skill still loads.
Write the description for routing
The description is the only thing the model sees before deciding to load the skill. State what the skill does and the trigger conditions ("Use when ..."), naming the concrete tasks, tools, and phrases a request would contain.
Good: Extracts text and tables from PDF files, fills PDF forms, and merges PDFs. Use when working with PDF documents.
Poor: Helps with PDFs.
Write the body for progressive disclosure
Keep SKILL.md short: the decision flow, the common commands, the contract. Push exhaustive detail (API schemas, full option lists, long examples) into references/*.md and link them, so they only enter context when actually needed. State setup steps (installs, env vars, credentials) explicitly and early.
Verification
After writing the skill:
- Re-read the frontmatter and check every rule in the table above, especially that
namematches the directory name and the description is non-empty. - In an interactive session,
/reloadpicks up new skills without a restart; other sessions pick them up on start. Loading problems (bad name, missing description, name collisions) surface as warnings — ask the user to check, or check diagnostics yourself if you can. - A loaded skill is also invocable as
/skill:<name>, which the user can try directly.
For Python-backed skills, also run the checks in references/python-skills.md.
