Modular Skill Creator

Architecture This Skill Produces

Every modular skill has three layers:

1. Router (SKILL.md) — loaded at invocation, under ~150 lines. Contains frontmatter, essential principles, intake logic, and routing rules only. No workflow prose lives here.

1. Workflows (workflows/*.md) — loaded on demand when the router decides which branch to execute. Each file is fully self-contained: it states its own inputs, prerequisites, steps, outputs, and done criteria.

1. References (references/*.md) — single-purpose data files (blacklists, templates, taxonomies, examples). Loaded by workflows when needed. Never contain procedural logic.

Core Rules

1. Router stays thin. If you catch yourself writing multi-step procedure logic in SKILL.md, it belongs in a workflow file.
2. Each workflow owns its scope. A workflow file should not need to read another workflow file to complete its job — unless the skill is explicitly a stage-pipeline where step N hands off to step N+1.
3. References are data, not logic. A reference file contains lookup tables, lists, templates, or examples. It never says "now do X."
4. Always ask project vs global. Per the user's global preference, never assume a save location — always ask before writing files.

Before anything else, ask where to save the output skill using AskUserQuestion:

> "Where should the new skill be saved?" > - Project-level — ./.claude/skills// in the current repo (preferred ~75% of the time) > - Skillshare global — ~/.config/skillshare/skills// (syncs to all your AI tools via skillshare)

Then ask what the user wants to do:

> "What would you like to do?" > - Build a new modular skill — design it from scratch with router + workflows + references > - Convert an existing skill — refactor a single-file SKILL.md into the modular pattern

Route based on the answer.

Workflow Routing

If user wants to build a new modular skill:

1. Read workflows/design-modular-skill.md — run the interview to produce the skill spec.
2. Read workflows/scaffold-router.md — generate the SKILL.md router from the spec.
3. Read workflows/scaffold-workflows.md — generate each workflows/*.md file from the spec.
4. Write all files to the save location confirmed in intake.

If user wants to convert an existing skill:

Read workflows/refactor-monolithic-skill.md. This workflow handles the full refactor end-to-end.

Reference Materials

• references/router-patterns.md — read this during scaffold-router to get the correct template for the chosen routing pattern (menu-driven, input-shape detection, or stage-pipeline)
• references/frontmatter-conventions.md — read this to use only fields the user's existing skills use; prevents spurious fields from appearing in generated skills
• references/examples.md — read this when you need a concrete canonical example to explain the pattern to the user or sanity-check your output against

Quality Checklist

Before reporting done:

• [ ] Router SKILL.md is under ~150 lines
• [ ] Router contains zero step-by-step procedure prose
• [ ] Every workflow file is self-contained (inputs, steps, outputs, done criteria all present)
• [ ] No allowed-tools field in frontmatter (not part of this user's convention)
• [ ] Description field is pushy and trigger-rich (50-100 words, lists trigger phrases)
• [ ] Save location was confirmed with user before any files were written

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: eristoddle
• Source: eristoddle/agent-skills
• License: MIT

Install and usage instructions live in the source repository linked above.