> hoocode can create skills. Ask it to build one for your use case.

# Skills

Skills are self-contained capability packages that the agent loads on-demand. A skill provides specialized workflows, setup instructions, helper scripts, and reference documentation for specific tasks.

HooCode implements the [Agent Skills standard](https://agentskills.io/specification), warning about violations but remaining lenient.

## Table of Contents

- [Locations](#locations)
- [Skills hoocode ships](#skills-hoocode-ships)
- [How Skills Work](#how-skills-work)
- [Skill Commands](#skill-commands)
- [Skill Structure](#skill-structure)
- [Frontmatter](#frontmatter)
- [Validation](#validation)
- [Example](#example)
- [Skill Repositories](#skill-repositories)

## Locations

> **Security:** Skills can instruct the model to perform any action and may include executable code the model invokes. Review skill content before use.

HooCode loads skills from:

- Global:
  - `~/.hoocode/skills/`
  - `~/.agents/skills/`
- Project:
  - `.hoocode/skills/`
  - `.agents/skills/` in `cwd` and ancestor directories (up to git repo root, or filesystem root when not in a repo)
- Packages: `skills/` directories or `hoocode.skills` entries in `package.json`
- Settings: `skills` array with files or directories
- CLI: `--skill <path>` (repeatable, additive even with `--no-skills`)
- Built-in: skills hoocode ships itself (see below)

Discovery rules:
- In `~/.hoocode/skills/` and `.hoocode/skills/`, direct root `.md` files are discovered as individual skills
- In all skill locations, directories containing `SKILL.md` are discovered recursively
- In `~/.agents/skills/` and project `.agents/skills/`, root `.md` files are ignored

Disable discovery with `--no-skills` (explicit `--skill` paths still load).

### Using Skills from Other Harnesses

To use skills from Claude Code or OpenAI Codex, add their directories to settings:

```json
{
  "skills": [
    "~/.claude/skills",
    "~/.codex/skills"
  ]
}
```

For project-level Claude Code skills, add to `.hoocode/settings.json`:

```json
{
  "skills": ["../.claude/skills"]
}
```

## Skills hoocode ships

hoocode ships a small set of its own skills. They are lowest precedence: a skill
of the same name from any other location — `--skill`, settings, `~/.agents/skills`,
`.hoocode/skills` — wins, and the collision is reported as a diagnostic. So
shipping one can never shadow a skill you wrote.

| Skill | Loaded when | Covers |
|---|---|---|
| `plugin-authoring` | `enablePluginTools` is on | When a capability is worth extracting, naming it so it triggers again, portability rules, and the hook trap where a changed command adds a second hook instead of replacing one. |

A skill costs its description on every turn, so one that only makes sense
alongside a feature rides that feature's switch rather than your token budget.
`plugin-authoring` is gated on the plugin system, which is off by default, so a
default session pays nothing for it.

`--no-skills` and `--light` suppress built-ins along with everything else.

**Where they live.** hoocode writes them to a content-addressed cache under
`~/.hoocode/cache/builtin-skills/<hash>/` and loads them from there. A skill is
loaded by `read`ing its file, so its location has to be a real path — and the
compiled standalone binary has no install directory to read from. Materializing
the same embedded copy on every install method keeps the skill set identical
across npm, pnpm, source and the binary. The directory is a cache: edit a copy
under `~/.agents/skills/` instead, which takes precedence anyway. If it cannot be
written (read-only home, full disk) the built-in skills are simply absent and
everything else runs normally.

## How Skills Work

1. At startup, hoocode scans skill locations and extracts names and descriptions
2. The system prompt includes available skills in XML format per the [specification](https://agentskills.io/integrate-skills)
3. When a task matches, the agent uses `read` to load the full SKILL.md (models don't always do this; use prompting or `/skill:name` to force it)
4. The agent follows the instructions, using relative paths to reference scripts and assets

This is progressive disclosure: only descriptions are always in context, full instructions load on-demand.

## Skill Commands

Skills register as `/skill:name` commands:

```bash
/skill:brave-search           # Load and execute the skill
/skill:pdf-tools extract      # Load skill with arguments
```

Arguments after the command are appended to the skill content as `User: <args>`.

Toggle skill commands via `/settings` in interactive mode or in `settings.json`:

```json
{
  "enableSkillCommands": true
}
```

## Skill Structure

A skill is a directory with a `SKILL.md` file. Everything else is freeform.

```
my-skill/
├── SKILL.md              # Required: frontmatter + instructions
├── scripts/              # Helper scripts
│   └── process.sh
├── references/           # Detailed docs loaded on-demand
│   └── api-reference.md
└── assets/
    └── template.json
```

### SKILL.md Format

````markdown
---
name: my-skill
description: What this skill does and when to use it. Be specific.
---

# My Skill

## Setup

Run once before first use:
```bash
cd /path/to/skill && npm install
```

## Usage

```bash
./scripts/process.sh <input>
```
````

Use relative paths from the skill directory:

```markdown
See [the reference guide](references/REFERENCE.md) for details.
```

## Frontmatter

Per the [Agent Skills specification](https://agentskills.io/specification#frontmatter-required):

| Field | Required | Description |
|-------|----------|-------------|
| `name` | Yes | Max 64 chars. Lowercase a-z, 0-9, hyphens. Must match parent directory. |
| `description` | Yes | Max 1024 chars. What the skill does and when to use it. |
| `license` | No | License name or reference to bundled file. |
| `compatibility` | No | Max 500 chars. Environment requirements. |
| `metadata` | No | Arbitrary key-value mapping. |
| `allowed-tools` | No | Space-delimited list of pre-approved tools (experimental). |
| `disable-model-invocation` | No | When `true`, skill is hidden from system prompt. Users must use `/skill:name`. |

### Name Rules

- 1-64 characters
- Lowercase letters, numbers, hyphens only
- No leading/trailing hyphens
- No consecutive hyphens
- Must match parent directory name

Valid: `pdf-processing`, `data-analysis`, `code-review`
Invalid: `PDF-Processing`, `-pdf`, `pdf--processing`

### Description Best Practices

The description determines when the agent loads the skill. Be specific.

Good:
```yaml
description: Extracts text and tables from PDF files, fills PDF forms, and merges multiple PDFs. Use when working with PDF documents.
```

Poor:
```yaml
description: Helps with PDFs.
```

## Validation

HooCode validates skills against the Agent Skills standard. Most issues produce warnings but still load the skill:

- Name doesn't match parent directory
- Name exceeds 64 characters or contains invalid characters
- Name starts/ends with hyphen or has consecutive hyphens
- Description exceeds 1024 characters

Unknown frontmatter fields are ignored.

**Exception:** Skills with missing description are not loaded.

Name collisions (same name from different locations) warn and keep the first skill found.

## Example

```
brave-search/
├── SKILL.md
├── search.js
└── content.js
```

**SKILL.md:**
````markdown
---
name: brave-search
description: Web search and content extraction via Brave Search API. Use for searching documentation, facts, or any web content.
---

# Brave Search

## Setup

```bash
cd /path/to/brave-search && npm install
```

## Search

```bash
./search.js "query"              # Basic search
./search.js "query" --content    # Include page content
```

## Extract Page Content

```bash
./content.js https://example.com
```
````

## Skill Repositories

- [Anthropic Skills](https://github.com/anthropics/skills) - Document processing (docx, pdf, pptx, xlsx), web development
- [HooCode Skills](https://github.com/badlogic/pi-skills) - Web search, browser automation, Google APIs, transcription