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skill-format.md

File metadata and controls

191 lines (144 loc) · 7.78 KB
summary Skill folder format, required files, allowed file types, limits.
read_when
Publishing skills
Debugging publish/sync failures

Skill format

On disk

A skill is a folder.

Required:

  • SKILL.md (or skill.md)

Optional:

  • any supporting text-based files (see “Allowed files”)
  • .clawhubignore (ignore patterns for publish/sync, legacy .clawdhubignore)
  • .gitignore (also honored)

Local install metadata (written by the CLI):

  • <skill>/.clawhub/origin.json (legacy .clawdhub)

Workdir install state (written by the CLI):

  • <workdir>/.clawhub/lock.json (legacy .clawdhub)

SKILL.md

  • Markdown with optional YAML frontmatter.
  • The server extracts metadata from frontmatter during publish.
  • description is used as the skill summary in the UI/search.

Frontmatter metadata

Skill metadata is declared in the YAML frontmatter at the top of your SKILL.md. This tells the registry (and security analysis) what your skill needs to run.

Basic frontmatter

---
name: my-skill
description: Short summary of what this skill does.
version: 1.0.0
---

Runtime metadata (metadata.openclaw)

Declare your skill's runtime requirements under metadata.openclaw (aliases: metadata.clawdbot, metadata.clawdis).

---
name: my-skill
description: Manage tasks via the Todoist API.
metadata:
  openclaw:
    requires:
      env:
        - TODOIST_API_KEY
      bins:
        - curl
    primaryEnv: TODOIST_API_KEY
---

Use requires.env for environment variables that must be present before the skill can run. Use envVars when you need per-variable metadata, including optional variables with required: false.

Full field reference

Field Type Description
requires.env string[] Required environment variables your skill expects.
requires.bins string[] CLI binaries that must all be installed.
requires.anyBins string[] CLI binaries where at least one must exist.
requires.config string[] Config file paths your skill reads.
primaryEnv string The main credential env var for your skill.
envVars array Environment variable declarations with name, optional required, and optional description. Set required: false for optional env vars.
always boolean If true, skill is always active (no explicit install needed).
skillKey string Override the skill's invocation key.
emoji string Display emoji for the skill.
homepage string URL to the skill's homepage or docs.
os string[] OS restrictions (e.g. ["macos"], ["linux"]).
install array Install specs for dependencies (see below).
nix object Nix plugin spec (see README).
config object Clawdbot config spec (see README).

Install specs

If your skill needs dependencies installed, declare them in the install array:

metadata:
  openclaw:
    install:
      - kind: brew
        formula: jq
        bins: [jq]
      - kind: node
        package: typescript
        bins: [tsc]

Supported install kinds: brew, node, go, uv.

Optional environment variables

Declare optional environment variables under metadata.openclaw.envVars and set required: false. Do not add optional entries to requires.env, because requires.env means the skill cannot run without them.

metadata:
  openclaw:
    primaryEnv: TODOIST_API_KEY
    envVars:
      - name: TODOIST_API_KEY
        required: true
        description: Todoist API token used for authenticated requests.
      - name: TODOIST_PROJECT_ID
        required: false
        description: Optional default project ID when the user does not specify one.

Why this matters

ClawHub's security analysis checks that what your skill declares matches what it actually does. If your code references TODOIST_API_KEY but your frontmatter doesn't declare it under requires.env, primaryEnv, or envVars, the analysis will flag a metadata mismatch. Keeping declarations accurate helps your skill pass review and helps users understand what they're installing.

Example: complete frontmatter

---
name: todoist-cli
description: Manage Todoist tasks, projects, and labels from the command line.
version: 1.2.0
metadata:
  openclaw:
    requires:
      env:
        - TODOIST_API_KEY
      bins:
        - curl
    primaryEnv: TODOIST_API_KEY
    envVars:
      - name: TODOIST_API_KEY
        required: true
        description: Todoist API token.
      - name: TODOIST_PROJECT_ID
        required: false
        description: Optional default project ID.
    emoji: "\u2705"
    homepage: https://github.com/example/todoist-cli
---

Allowed files

Only “text-based” files are accepted by publish.

  • Extension allowlist is in packages/schema/src/textFiles.ts (TEXT_FILE_EXTENSIONS).
  • Content types starting with text/ are treated as text; plus a small allowlist (JSON/YAML/TOML/JS/TS/Markdown/SVG).

Limits (server-side):

  • Total bundle size: 50MB.
  • Embedding text includes SKILL.md + up to ~40 non-.md files (best-effort cap).

Slugs

  • Derived from folder name by default.
  • Must be lowercase and URL-safe: ^[a-z0-9][a-z0-9-]*$.

Versioning + tags

  • Each publish creates a new version (semver).
  • Tags are string pointers to a version; latest is commonly used.

License

  • All skills published on ClawHub are licensed under MIT-0.
  • Anyone may use, modify, and redistribute published skills, including commercially.
  • Attribution is not required.
  • Do not add conflicting license terms in SKILL.md; ClawHub does not support per-skill license overrides.

Paid skills

  • ClawHub does not support paid skills, per-skill pricing, paywalls, or revenue sharing.
  • Do not add pricing metadata to SKILL.md; it is not part of the skill format and will not make a published skill paid.
  • If your skill integrates with a paid third-party service, document the external cost and required account clearly in the skill instructions and env declarations (requires.env for required variables, or envVars with required: false for optional variables).