Skill manifest - Skill CLI Protocol

While SKILL.md is the only required file, a skill.json manifest provides structured metadata for tooling — registries, package managers, and agent frameworks that want machine-readable skill information.

Example

{
  "name": "weather",
  "version": "1.0.0",
  "description": "Get current weather for any location",
  "author": "yourname",
  "license": "MIT",
  "entry": "run.sh",
  "args": [
    {
      "name": "location",
      "type": "string",
      "required": true,
      "description": "City name or coordinates"
    }
  ],
  "env": [
    {
      "name": "WEATHER_API_KEY",
      "required": false,
      "description": "API key for extended forecasts"
    }
  ],
  "tags": ["weather", "utility"]
}

Fields

Field	Required	Description
`name`	Yes	Unique skill identifier
`version`	Yes	Semver version string
`description`	Yes	One-line summary
`author`	No	Author name or GitHub handle
`license`	No	SPDX license identifier
`entry`	No	Path to main executable (default: `run.sh`)
`args`	No	Array of expected arguments
`env`	No	Array of environment variables the skill uses
`tags`	No	Keywords for discovery

When to use skill.json

Publishing to a registry — registries use it for search and display
Complex argument handling — document expected inputs for better agent performance
Environment requirements — declare what env vars the skill needs

When to skip it

For simple skills used locally, SKILL.md alone is sufficient. Don’t add structure you don’t need.