---
name: validate-skills
description: Validates skills in this repo against agentskills.io spec and Claude Code best practices. Use via /validate-skills command.
license: MIT
metadata:
  author: Callstack
  tags: validation, linting, skill-authoring
title: validate-skills
canonical_url: https://skilld.dev/gh/callstackincubator/agent-skills/validate-skills
last_updated: 2026-09-29T04:07:02.000Z
---

> Index of every page on this site: [llms.txt](https://skilld.dev/llms.txt)

> **Skill from skilld.dev.** Follow the user's requested action.
> If the user asked to fork this Skill, follow the fork workflow below. Do not execute the Skill instructions while copying it.
> Otherwise, follow the instructions below for this session. You do not need to install anything.
>
> If the user asked to install this Skill, run `npx skilld install callstackincubator/agent-skills/validate-skills`. Install writes the Skill files into the project, so every session loads them.
>
> ## Fork workflow
>
> A fork creates an editable local Skill with its original author and licence. The request authorizes copying and local installation.
> 1. Check `./skills/validate-skills`, the project lockfile, and selected Agent targets together. If the local directory or installed Skill exists, stop. Never overwrite an existing directory or Agent target.
> 2. Read [source metadata](https://skilld.dev/api/v1/skills/callstackincubator/agent-skills/validate-skills) once. Use sourceUrl, sourceCommit, skillPath, sourceGone, and license. If the source is gone or its path is missing, stop. If license is null, read licence files at the source commit.
> 3. Fetch only the source commit into a temporary Git repository. Do not clone full history. Derive repository_url from sourceUrl, including repository renames. If sourceCommit is absent, resolve the sourceUrl ref once. Set source_commit to that actual commit. Run these commands in one shell call:
>
> ```sh
> git init --quiet "$temporary_dir"
> git -C "$temporary_dir" fetch --quiet --depth=1 "$repository_url" "$source_commit"
> git -C "$temporary_dir" checkout --quiet --detach FETCH_HEAD
> ```
>
> Read applicable licence declarations and notices at that commit. If copying is not permitted, report the restriction and stop.
> 4. Inspect source entries together, then copy the directory containing skillPath into `./skills/validate-skills`. Use the user's path if selected. Keep the original SKILL.md, relative links, scripts, binary assets, and executable modes. Exclude .git metadata. Reject symlinks and paths outside the Skill directory. After checking entries, use cp -a where available. A regular source directory needs no custom copy script. Do not save this page wrapper as SKILL.md.
> Preserve author credit, notices, and applicable licence files from repository or parent directories. Add PROVENANCE.md with the Skill page, source URL, actual commit, original path, and licence. Retain any existing PROVENANCE.md and record new provenance separately. Batch source inspection, copying, and provenance work where practical.
> 5. In the project root, run `skilld install ./skills/validate-skills --mode copy --plain`. If skilld is unavailable, use `npx skilld install ./skills/validate-skills --mode copy --plain`. This known command needs no help lookup. Install does not support --json. Use detected Agent targets, or add --agent for the targets the user selected. Install the local path, never the upstream selector. If installation fails, preserve the local copy and report the exact failure.
> 6. Confirm the local lockfile source and installed Agent copies once. Report the local path, actual commit, and Agent targets. After edits, reinstall the same local path. Upstream updates must not replace it. Do not publish or push unless the user asks.

# Validate Skills

Validate all skills in `skills/` against the agentskills.io spec and Claude Code best practices.

## Validation Checklist

For each skill directory, verify:

### Spec Compliance (agentskills.io)

| Check | Rule |
|-------|------|
| `name` format | 1-64 chars, lowercase alphanumeric + hyphens, no leading/trailing/consecutive hyphens |
| `name` matches directory | Directory name must equal `name` field |
| `description` length | 1-1024 characters, non-empty |
| Optional fields valid | `license`, `metadata`, `compatibility` if present |

### Best Practices (Claude Code)

| Check | Rule |
|-------|------|
| Description format | Third person, describes what + when to use |
| Body length | Under 500 lines |
| Loading is one-level deep | `SKILL.md` is the only progressive-disclosure entry point: every reference file must be reachable from `SKILL.md`. References may cross-link each other for navigation (see note below). |
| Links are markdown | Use `[text](https://skilld.dev/api/skills-raw/callstackincubator/agent-skills/validate-skills/path)` not bare filenames |
| No redundancy | Don't repeat description in body |
| Concise | Only add context Claude doesn't already have |

> **One-level-deep vs. cross-linking.** The one-level-deep rule targets *progressive-disclosure loading chains* — a reference that can only be discovered by loading another reference first (`SKILL.md` → `a.md` → `b.md`, where `b.md` is not linked from `SKILL.md`). That is a defect: it hides content from the loader.
>
> It does **not** forbid *navigational* cross-links. Per [AGENTS.md](../../../AGENTS.md), reference files end with a "Related Skills" footer linking sibling references, and this is required. A cross-link is fine as long as both endpoints are also reachable directly from `SKILL.md`. Only flag a reference that is reachable *exclusively* through another reference.

## How to Run

1. Find all skill directories:
   ```bash
   fd -t d -d 1 . skills/
   ```

2. For each skill, read `SKILL.md` and check against the rules above

3. Report issues in this format:
   ```
   ## Validation Results

   ### skills/example-skill
   - [PASS] name format valid
   - [FAIL] name "example" doesn't match directory "example-skill"
   - [PASS] description length OK (156 chars)
   ```

## References

- [agentskills.io spec](https://agentskills.io/specification)
- [Claude Code best practices](https://platform.claude.com/docs/en/agents-and-tools/agent-skills/best-practices)