Claude Skill Builder
Build Anthropic / Claude Agent Skills from VS Code.
Claude Skill Builder gives you a local workbench for creating Claude-compatible SKILL.md folders, drafting from free-form ideas, packaging skills for Claude.ai upload, validating skill structure, and syncing skills into Claude Code for local testing.
What It Creates
The extension creates standard Claude skill folders:
skills/
my-skill/
SKILL.md
references/
scripts/
assets/
evals/evals.json
It can also create authoring notes under:
workbench/
my-skill/
brief.md
authoring-prompt.md
Only skills/<skill-name>/ is the Claude skill deliverable. workbench/ is for planning, notes, and iteration.
Quick Start
- Open a workspace in VS Code.
- Open the Explorer sidebar.
- Find the
Claude Skills view.
- Click
Skill Builder: Interactive Builder.
- Describe the workflow you want as normal text.
- Click
Create Skill Draft.
The interactive builder creates a starter SKILL.md, starter evals, and a workbench brief from one form.
Create A Skill From A Rough Idea
Use Skill Builder: Interactive Builder when you are still thinking out loud.
Good input looks like:
I need a skill that turns messy Jira security architecture updates into a weekly executive-ready status report. It should use our preferred sections, flag blockers, and create copy I can paste into Confluence.
Optional fields let you add:
- target surface: portable, Claude.ai, Claude Code, or Claude API
- trigger description
- should-trigger and should-not-trigger examples
- inputs Claude should gather
- workflow steps Claude should follow
- edge cases and decision points
- quality checks
- output standard
- examples, templates, and source materials
- references, assets, and progressive-disclosure plan
- reference files to create under
references/
- script plan
- script stubs to create under
scripts/
- asset placeholders to create under
assets/README.md
- eval prompts
- target-surface notes
- external systems or MCP dependencies
- security and trust notes
When detailed fields are filled in, the extension also writes a workbench creation plan:
workbench/<skill-name>/creation-plan.md
That plan walks through trigger design, progressive disclosure, script rules, eval design, target-surface constraints, security, and the done checklist for a production-grade skill.
If you list reference or script files in the form, the extension creates starter files for them. Asset entries create notes in assets/README.md; copy binary templates, images, or sample files into assets/ manually.
Add Existing Docs, Scripts, Or Assets
If you already have files, right-click a skill in the Claude Skills tree and choose:
Skill Builder: Add Supporting Files
Then choose where the files belong:
references/ for Markdown docs, policies, schemas, examples, style guides, and other material Claude should read only when needed.scripts/ for deterministic helpers. Scripts should be non-interactive, support --help, use structured output when practical, and avoid hidden network or package-install assumptions.assets/ for templates, images, sample files, static tables, and other resources used by the skill.
The extension copies the selected files into the chosen folder and adds a small README.md note in that folder. After adding files, update SKILL.md so Claude knows when to read the reference, run the script, or use the asset.
Package For Claude.ai
Right-click a skill in the Claude Skills tree and choose:
Skill Builder: Package Skill
The extension writes:
dist/<skill-name>.zip
The ZIP preserves the skill folder inside the archive, which is the structure Claude.ai expects for custom skill upload.
Sync To Claude Code
Right-click a skill and choose:
Skill Builder: Sync to Claude Code
By default, the extension copies the skill to:
~/.claude/skills/<skill-name>/
You can override the destination with:
skillBuilder.claudeCodeSkillsDirectory
After syncing, Claude Code can discover the skill from the filesystem.
Validate A Skill
Right-click a skill and choose:
Skill Builder: Validate Skill
This opens an integrated terminal and runs:
skills-ref validate "<skill-path>"
Install skills-ref separately if you want validation to run locally.
Commands
Skill Builder: Interactive Builder opens the free-form skill intake UI.Skill Builder: Create Skill creates a minimal starter skill through prompts.Skill Builder: Open Skill opens the selected SKILL.md.Skill Builder: Add Supporting Files copies existing docs, scripts, or assets into a skill.Skill Builder: Package Skill creates a Claude.ai upload ZIP.Skill Builder: Sync to Claude Code copies a skill to the Claude Code skills folder.Skill Builder: Validate Skill runs skills-ref validate.Skill Builder: Copy Free-Form Chat Prompt copies a prompt for deeper skill authoring work with an AI assistant.
Settings
skillBuilder.skillsDirectory: workspace-relative skill source directory. Default: skills.skillBuilder.distDirectory: workspace-relative ZIP output directory. Default: dist.skillBuilder.claudeCodeSkillsDirectory: sync destination for Claude Code. Default: ~/.claude/skills.skillBuilder.projectRoot: optional project root override.
What This Extension Does Not Do
Claude Skill Builder does not upload skills into Claude.ai or the Claude API for you. It prepares the folder or ZIP artifact locally.
It also does not run Claude inside VS Code. The interactive builder creates a strong local draft and an optional authoring prompt, but deeper refinement still happens by editing the generated files or using your preferred AI assistant.
Security Notes
Treat skills like installable software. Review bundled scripts, dependencies, assets, and instructions that access external systems.
Do not hardcode secrets in a skill. For external services, prefer MCP-oriented instructions and document required tools and permissions clearly.
License
MIT License. See LICENSE.
Official References
Development
Install dependencies:
npm install
Compile:
npm run compile
Package:
npm run package
