skill-creator

Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Claude's capabilities with specialized knowledge, workflows, or tool integrations.

Install with Tessl CLI

npx tessl i github:vercel-labs/agent-browser --skill skill-creator

What are skills?

Overall
score

81%

Review — 76%

Does it follow best practices?

If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:

npx tessl skill review --optimize ./path/to/skill

Learn more

Evaluation — 79%

↑ 1.23x

Agent success when using this skill

Validation — 14 / 16 Passed

Validation for skill structure

SKILL.md

Review

Evals

Evaluation results

100%

65%

Build a CSV Data Analyzer Skill

New skill initialization and creation workflow

Criteria

Without context

With context

Init script usage

100%

SKILL.md exists

100%

Correct directory structure

100%

No extraneous docs

100%

Frontmatter has name

100%

Frontmatter has description

100%

No extra frontmatter fields

100%

Name is hyphen-case

100%

Scripts directory present

100%

References directory present

100%

Example files cleaned up

100%

Log documents steps

100%

62%

Create an Email Campaign Builder Skill

Effective SKILL.md writing and frontmatter

Criteria

Without context

With context

Description includes triggers

100%

No 'when to use' in body

100%

Description under 1024 chars

100%

No angle brackets in description

100%

Only name and description in frontmatter

100%

Imperative voice in body

60%

100%

Concise skill body

100%

Examples over explanations

20%

100%

Style guide in references

100%

Template in assets

100%

References linked from SKILL.md

100%

90%

25%

Create a Multi-Cloud Infrastructure Deployment Skill

Progressive disclosure and resource organization

Criteria

Without context

With context

Separate provider reference files

100%

SKILL.md under 500 lines

100%

References linked from SKILL.md

100%

No content duplication

100%

Flat reference structure

100%

TOC in long reference files

Cross-provider policies separate

100%

Terraform scaffold script

100%

Selection guidance in SKILL.md

100%

No extraneous files

100%

10%

-75%

Create a Database Migration Skill

Degrees of freedom and workflow design

Criteria

Without context

With context

Low freedom for column drops

100%

High freedom for new tables

100%

Medium freedom for indexes

100%

Sequential workflow for dangerous ops

100%

Script for fragile operation

100%

Conditional workflow routing

Concise body

100%

Imperative form

100%

Design rationale explains freedom levels

100%

No extraneous docs in skill

100%

Tested scripts

95%

Improve and Package an Existing API Client Skill

Iterating and packaging existing skill

Criteria

Without context

With context

README.md removed

100%

CHANGELOG.md removed

100%

Example script removed

100%

Placeholder reference removed

100%

Placeholder asset removed

100%

Extra frontmatter fields removed

100%

Description improved

100%

When to use section removed from body

100%

Content split into references

100%

SKILL.md under 500 lines

100%

Packaging mentioned

References linked from SKILL.md

100%

Evaluated: 14 days ago
Agent: Claude Code

Table of Contents

Build a CSV Data Analyzer Skill Create an Email Campaign Builder Skill Create a Multi-Cloud Infrastructure Deployment Skill Create a Database Migration Skill Improve and Package an Existing API Client Skill

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.