🤖 Copilot Assets Studio

Visually edit the YAML frontmatter of GitHub Copilot AI artifacts: agents, skills, instructions, and prompts.

Features

This Visual Studio Code extension:

• discovers Copilot/Agent Customizations assets in the workspace (excluding node_modules)
• displays a Copilot Assets sidebar tree with Agents, Skills, Instructions, Prompts, MCP Servers, and Plugins; Agents, Skills, Instructions, and Prompts open in visual forms, while MCP Servers (.vscode/mcp.json) and Plugins (plugin.json) open as regular files
• lets you create and edit *.agent.md files through a visual form
• lets you create and edit SKILL.md files through a visual form
• lets you create and edit *.instructions.md files (name, description, applyTo) through a visual form
• lets you create and edit *.prompt.md files through a visual form; prompt files are deprecated and reusable prompts should migrate to agent skills
• shows collapsible, live validation and advice in the agent form (including YAML errors, unknown properties, tool/agent configuration rules, and GitHub cloud's 30,000-character instruction limit)
• supports three modes for agent tools and agents: selected values, all (*), and none ([])
• shows separate approximate token counts for YAML frontmatter and Markdown, plus their total, in all editor forms; each section uses UTF-8 bytes / 4 (rounded up), not a model-specific bill or total conversation cost
• includes a Markdown preview of the body in the editors
• supports the officially documented properties for agent frontmatter
• preserves extra and unknown properties through an advanced YAML block, keeping parse/serialize round trips intact

The model field is edited through a selector. The default list can be customized in VS Code settings with copilotAssetsStudio.modelOptions, for example:

{
  "copilotAssetsStudio.modelOptions": [
    "GPT-5 (copilot)",
    "Claude Sonnet 4.5 (copilot)"
  ]
}

For local development, testing, and packaging instructions, see DEVELOPMENT.md.

References

• Repository: https://github.com/marrubio/copilot-assets-studio
• VS Code extension documentation: https://code.visualstudio.com/api
• Publishing VS Code extensions: https://code.visualstudio.com/api/working-with-extensions/publishing-extension
• GitHub Copilot custom agents: https://docs.github.com/en/copilot/reference/custom-agents-configuration
• VS Code custom agents: https://code.visualstudio.com/docs/agent-customization/custom-agents
• GitHub Copilot agent skills: https://docs.github.com/en/copilot/concepts/agents/about-agent-skills
• VS Code prompt files: https://code.visualstudio.com/docs/agent-customization/prompt-files