Skill Fork

Skill Fork — The Splitter

Decompose oversized or multi-responsibility skills into focused child skills that stay connected through the registry's relationship graph.

When to Fork

A skill is a fork candidate when ANY of:

• body_words > 2000 (health warning threshold)
• section_count > 6 (doing too much)
• Sections cover clearly distinct responsibilities (e.g., "creation" + "analysis" in one skill)
• The user explicitly requests decomposition
• skill-analyze suggests splitting

Fork Process

1. Analyze the Parent

Read the parent SKILL.md and identify natural split points:

• Group ## sections by responsibility cluster
• Check which references belong to which cluster
• Map dependencies per cluster (which tools, which other skills)
• Read references/decomposition-strategies.md for strategy patterns

2. Plan the Fork

Present a decomposition plan before executing:

FORK PLAN — skill-big-skill
━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Parent:  skill-big-skill (2,847 words, 9 sections)
Strategy: responsibility-split

Child 1: skill-big-skill-create
  Sections: ## Creation, ## Templates, ## Validation
  Est. words: ~1,100
  References: templates/, creation-guide.md

Child 2: skill-big-skill-analyze
  Sections: ## Analysis, ## Metrics, ## Reporting
  Est. words: ~950
  References: analysis-patterns.md, metrics.md

Child 3: skill-big-skill-manage
  Sections: ## Lifecycle, ## Configuration, ## Updates
  Est. words: ~800
  References: config-schema.md

Shared: references/common-types.md → shares_references_with

3. Execute the Fork

After user confirmation:

1. Create each child skill directory using skill-scaffold patterns
2. Move relevant sections from parent SKILL.md to each child
3. Move relevant reference files to each child's references/
4. Copy shared references and update shares_references_with
5. Update each child's frontmatter (name, description, tools)
6. Register children in the registry with forked_from: parent-name
7. Update parent with forked_into: [child-1, child-2, ...]
8. Set parent status to deprecated with replacement_skill naming the primary child (note others in deprecation_reason)
9. Run skill-health validation on each child

4. Post-Fork Verification

• All children pass structural validation
• Combined children cover all parent sections (nothing lost)
• Cross-references between children are correct
• Registry relationships are bidirectional
• Parent's referenced_by skills now point to appropriate children

Output Format

FORK COMPLETE — skill-big-skill
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Parent:   deprecated → see children
Children: 3 created, all healthy

  ✓ skill-big-skill-create   1,100 words  score: 100
  ✓ skill-big-skill-analyze    950 words  score: 100
  ✓ skill-big-skill-manage     800 words  score: 100

Registry updated. Run /skill-status to verify.