@agenshield/skills

Skill loader, validator, registry, and executor for OpenClaw-compatible skills, plus "Soul" system prompt injection utilities.

Purpose

• Parse SKILL.md files with YAML frontmatter.
• Validate skill manifests for basic correctness.
• Register and look up skills in memory.
• Execute skills with optional policy checks and audit logging.
• Inject security guidance into system prompts (Soul).

Key Components

• src/loader.ts - Loads and parses SKILL.md files.
• src/validator.ts - Validates skill manifests and content.
• src/registry.ts - In-memory registry of loaded skills.
• src/executor.ts - Executes skill commands via spawn.
• src/soul/* - Soul prompt templates and injector.

Usage

Load and register skills

import { SkillLoader, SkillRegistry } from '@agenshield/skills';

const loader = new SkillLoader();
const registry = new SkillRegistry();

const skills = await loader.loadFromDirectories([
  '/opt/agenshield/skills',
  '/Users/clawagent/.agenshield/skills',
]);

registry.registerAll(skills);

Validate a skill

import { validateSkill } from '@agenshield/skills';

const result = validateSkill(skill);
if (!result.valid) {
  console.error(result.errors);
}

Execute a skill

import { SkillExecutor } from '@agenshield/skills';

const executor = new SkillExecutor({
  checkPolicy: async (operation, target) => true,
  auditLog: (entry) => console.log(entry),
});

const result = await executor.execute(skill, {
  args: ['echo hello'],
  timeout: 30000,
});

Soul injection

import { SoulInjector } from '@agenshield/skills';

const injector = new SoulInjector({ mode: 'prepend', securityLevel: 'high' });
const prompt = injector.inject('Original system prompt', {
  workspacePath: '/Users/clawagent/workspace',
  allowedOperations: ['read', 'list'],
});

SKILL.md Format

Skills use YAML frontmatter plus Markdown body:

---
name: security-check
description: Check security status
user-invocable: true
command-dispatch: bash
command-arg-mode: single
requires:
  bins:
    - shieldctl
agenshield:
  policy: builtin-security-check
  allowed-commands:
    - shieldctl status
---

# Skill Title

Detailed instructions...

Built-in Skills

This repo ships example skills under libs/shield-skills/skills/:

• security-check
• secret-broker
• policy-enforce
• soul-shield

The library does not auto-load these; consumers must load them explicitly via SkillLoader.

Limitations and Caveats

• The YAML parser is intentionally simple; complex YAML features are not supported.
• SkillExecutor runs commands via spawn and does not sandbox execution on its own.
• allowedCommands is only enforced if the caller provides a checkPolicy function.
• There is no built-in persistence for skill registries.

Roadmap (Ideas)

• Replace the YAML parser with a full YAML library.
• Add execution backends that route through the broker by default.
• Richer validation (schema versioning, OS/platform constraints).
• Streaming execution output and structured results.

Development

# Build
npx nx build shield-skills

Contribution Guide

• Keep the manifest contract backward compatible; prefer additive changes.
• Update src/types.ts and src/validator.ts together.
• Add new Soul templates in src/soul/templates.ts and expose via getSoulContent().

Agent Notes

• SkillLoader.parseManifest() expects frontmatter and uses indentation for nesting.
• Skills are normalized to the Skill interface; missing fields are defaulted.
• SkillExecutor.buildCommand() controls dispatch for bash, node, and python.
• Built-in skills live in libs/shield-skills/skills/ for reference/testing.