Composing Skills

The composes[] field on a skill manifest lets a skill inherit the tools and prompt context of other skills. This is the primary mechanism for building meta-skills — high-level capabilities that combine several lower-level skills without duplicating their definitions.

Example

Define a meta-skill that composes two existing skills:

# skills/advanced-research/manifest.yml
id: advanced_research
name: Advanced Research
description: Full-stack research skill combining search and analysis
tools:
  - research_runner
composes:
  - search_skill      # inherits all search_skill tools
  - analysis_skill    # inherits all analysis_skill tools

How tool inheritance works

// getSkillToolNames() recursively resolves the full tool list
getSkillToolNames(['advanced_research'])
// Returns: ['research_runner', 'web_search', 'fetch_page', 'analyse_data', 'chart']
//           ^ own tool         ^ from search_skill         ^ from analysis_skill

Recursion and cycle protection

• composes[] is resolved recursively — a composed skill can itself compose other skills
• A visited set prevents infinite loops from circular compositions
• Prompt context from all composed skills is merged and deduplicated before injection

Prompt context merging

// Context from all composed skills is collected in order
getSkillPromptContext(['advanced_research'])
// Produces a merged block:
// [advanced_research context]
// [search_skill context]
// [analysis_skill context]

Rules

• A skill cannot compose itself (cycle guard)
• Tool names from composed skills are deduplicated (Set)
• A skill's own tools take precedence in ordering; composed tools follow
• composes[] accepts skill IDs, not file paths