Create Skill

Skill & Command Generator

Generate well-structured skills or slash commands. Both are markdown files with YAML frontmatter—they share the same structure but differ in how they're triggered and described.

Phase 0: Fetch Current Documentation

Before generating, retrieve the latest documentation:

Use Task tool with subagent_type=claude-code-guide:
"List all current frontmatter options for skills and commands, including any execution modifiers, model selection, and structural options."

Capture any frontmatter fields or options not already listed in references/frontmatter-options.md. If nothing new, proceed with current references. If the subagent fails, proceed — current references are sufficient.

Phase 1: Understand Requirements

Parse $ARGUMENTS for type hint. User is often unclear and uninformed on best practices of skill development. Continue to interview and help user using /brainstorm skill, if available.

Gather requirements:

1. Primary objective — What should this do?
2. Trigger scenarios — When should it activate?
3. Inputs/outputs — What does it receive and produce?
4. Complexity — Simple, standard, or complex?
5. Execution needs — Isolated context? Delegated to specialized agent?

Proceed to Phase 2 when at minimum Objective and Trigger Scenarios are established. Remaining dimensions can be resolved during generation.

Phase 2: Generate

Apply these principles throughout generation: use imperative voice and terse phrasing because every token in a generated skill body costs budget on every invocation, and Claude extrapolates well from precise nudges. Prefer instruction over example — state the rule with its reasoning so it generalizes to every input.

Step 1 — Choose type

• Skills: Trigger-rich, third-person description ("This skill should be used when..."); auto-triggered by routing
• Commands: Concise, verb-first description, under 60 chars; user-invoked via / menu

Step 2 — Write frontmatter

Read ${CLAUDE_PLUGIN_ROOT}/skills/create-skill/references/frontmatter-options.md for the full field catalog, description patterns, tool selection framework, and execution modifiers.

Intensional over extensional — apply to all generated content. State the rule directly with its reasoning rather than listing examples that imply the rule. An intensional rule ("quoted phrases must be verbatim user speech because routing matches on literal tokens") generalizes to every input the skill will encounter. An extensional approach requires the reader to reverse-engineer the rule — two reasoning hops instead of one, covering only the shape of those specific examples. Since this skill generates instructions that will themselves guide further generation, the quality of reasoning propagates.

Step 3 — Write body

Construction rules:

• State objective explicitly in first sentence
• Use imperative voice ("Analyze", "Generate", "Identify") — no first-person ("I will", "I am")
• Context only when necessary for understanding
• XML tags only for complex structured data
• No "When to Use This Skill" section — body loads only after triggering; routing guidance there is never read by the routing decision
• Avoid headers deeper than H3 — deep nesting signals content that belongs in references/, not SKILL.md
• Use bang-backtick syntax for dynamic context injection when real-time data (git status, file list, env vars) improves the skill without requiring a tool call

Both skills and commands follow the same body pattern:

# Name

Brief overview (1-2 sentences).

## Process
1. Step one (imperative voice)
2. Step two
3. Step three

Dynamic Content:

Step 4 — Script opportunity scan

Read ${CLAUDE_PLUGIN_ROOT}/skills/create-skill/references/script-patterns.md and apply the five signal patterns to every workflow step in the skill being generated:

For each identified script candidate:

1. Choose the archetype from references/script-patterns.md (init/validate/transform/package/query)
2. If the interface is non-trivial, delegate to create-cli skill to design it
3. Scaffold the script in scripts/ using the Python template from references/script-patterns.md
4. Wire it into SKILL.md with: trigger condition, exact invocation, output interpretation

Wiring rule: A script reference must state when to invoke (trigger condition), how to invoke (exact command with flags), and what to do with the result (exit code handling, which output fields matter).

Step 5 — Check delegation

Scan for existing resources before finalizing:

Review available: skills, commands, agents, MCPs
For each workflow step, ask: "Do we already have this?"

Common delegation patterns:

• Git commits → SlashCommand: /commit
• Code review → Skill: /code-review

Always use fully qualified names:

• Skill: plugin-dev:hook-development (not just "hook-development")
• SlashCommand: /plugin-dev:create-plugin (not just "create-plugin")
• Task: subagent_type=plugin-dev:agent-creator

Step 6 — Validate

When generating a new skill directory (not editing an existing single file):

python3 ${CLAUDE_PLUGIN_ROOT}/skills/create-skill/scripts/validate_skill.py <skill-directory> --output json

Exit 0 = proceed to Phase 3. Exit 1 = parse the errors array; each entry has field, message, severity. Resolve all critical and major items before writing to disk.

Explain Your Choices

When presenting the generated skill/command to the user, briefly explain:

• What you set and why — "Added context: fork because this workflow generates heavy output"
• What you excluded and why — "Left model unset (inherits default), hooks omitted (no validation needed)"
• Add more trigger phrases if routing misses expected inputs

Phase 3: Deliver

Output Paths

Write and Confirm

Before writing:

Writing to: [path]
This will [create new / overwrite existing] file.
Proceed?

After Creation

Summarize what was created:

• Name and type
• Path
• How to invoke/trigger
• Suggested test scenario

Phase 4: Evaluate

Score the generated skill/command:

Target: 9.0/10.0. If below, refine once addressing the weakest dimension, then deliver.

Bundled Scripts

Initialize a new skill — invoke at Step 1 when creating a new skill directory (not when editing an existing file):

python3 ${CLAUDE_PLUGIN_ROOT}/skills/create-skill/scripts/init_skill.py <name> --path <dir> [--resources scripts,references,assets] [--examples]

Exit 0 = directory created, proceed to Step 2. Exit 1 = naming collision; ask user whether to overwrite or rename.

Validate a skill — invoke at Step 6 before delivering:

python3 ${CLAUDE_PLUGIN_ROOT}/skills/create-skill/scripts/validate_skill.py <skill-directory> --output json

Exit 0 = proceed to Phase 3. Exit 1 = parse errors array; resolve all critical and major items before writing.

Package for distribution — invoke only when user explicitly requests a distributable file:

python3 ${CLAUDE_PLUGIN_ROOT}/skills/create-skill/scripts/package_skill.py <skill-directory> [output-dir]

Exit 0 = .skill file created at output path. Exit 1 = validation failed; read stdout for details.

Degrees of Freedom

Match instruction specificity to the task's fragility and variability:

Quality Standards

Format Economy:

• Simple task → direct instruction, no sections
• Moderate task → light organization with headers
• Complex task → full semantic structure

Balance Flexibility with Precision:

• Loose enough for creative exploration
• Tight enough to prevent ambiguity

Remove ruthlessly: Filler phrases, obvious implications, redundant framing, excessive politeness

Validation Checklist

Before finalizing a skill or command:

Structure:

• SKILL.md file exists with valid YAML frontmatter
• Frontmatter has name and description fields
• Markdown body is present and substantial
• Referenced files actually exist

Description Quality:

• Uses third person ("This skill should be used when...")
• Includes specific trigger phrases users would say
• Lists concrete scenarios ("create X", "configure Y")
• Not vague or generic

Content Quality:

• Body uses imperative/infinitive form, not second person
• Body is focused and lean (1,500–2,000 words ideal, <5k max)
• Detailed content moved to references/
• Examples are complete and working
• Scripts are executable and documented
• Script opportunities identified via five signal patterns (references/script-patterns.md)
• Script references in SKILL.md include trigger condition, invocation, output handling
• Consistency-critical steps are scripted, not left to LLM re-generation

Progressive Disclosure:

• Core concepts in SKILL.md
• Detailed docs in references/
• Working code in examples/
• Utilities in scripts/
• SKILL.md references these resources

Testing:

• Skill triggers on expected user queries
• Content is helpful for intended tasks
• No duplicated information across files
• References load when needed

Error Handling

Execute phases sequentially. Always fetch current documentation first.