Vestigium

Make every addition belong to the same product.

Vestigium is a design skill for coding agents. It helps an agent extend and refine an interface without gradually replacing its visual identity: inspect the existing work, reuse its components and design decisions, follow supplied references, and verify the result in context.

Works with Codex, Claude Code, and Pi through the open SKILL.md format. No runtime dependencies, API keys, MCP server, hooks, or telemetry. Optional image generation and browser checks use tools already available to your agent.

What it changes

When you ask for a settings page, contact form, or another landing-page section, Vestigium tells the agent to:

• Find the existing component, token, or layout pattern before creating another one.
• Carry spacing, typography, color roles, and corner treatments across the whole interface.
• Treat inputs, opened pickers, focus, validation, and action spacing as part of the design.
• Preserve the distinctive geometry and composition of a supplied reference.
• Check neighboring sections, responsive layouts, and affected interactions before reporting completion.

Its preferences favor clear hierarchy and restrained decoration. They are opinionated defaults, and your explicit brief and approved project conventions take precedence. It does not impose a universal palette or component library.

Install

The npm installer requires Node.js 22 or newer. Manual installation needs no Node.js.

Codex

npx @koboimomo/vestigium install --agent codex

Installs a persistent copy to ~/.agents/skills/vestigium. Restart Codex, then use:

$vestigium Add a contact section using this page's existing design system.

Claude Code

npx @koboimomo/vestigium install --agent claude

Installs to ~/.claude/skills/vestigium. Restart Claude Code, then use:

/vestigium Make the settings form consistent with the rest of this app.

Pi

pi install npm:@koboimomo/vestigium

Restart Pi or run /reload, then use:

/skill:vestigium Extend this landing page while preserving its visual identity.

For a plain folder installation instead of a managed Pi package:

npx @koboimomo/vestigium install --agent pi

Choose one installation route per agent. Pi also discovers ~/.agents/skills; if you already installed there for Codex and Pi finds Vestigium, no second Pi installation is needed.

Manual or project installation

Download this repository and copy the entire skills/vestigium directory, including references and agents, into the appropriate location:

Other agents that support the Agent Skills format can load the same folder. Tool availability and discovery paths depend on the host. See the official Codex, Claude Code, and Pi documentation for host behavior.

Use it in real work

Use Vestigium to add billing settings. Reuse our existing form groups,
buttons, spacing, and error states. Keep the rest of the app unchanged.

Use Vestigium to reproduce this reference's composition with our content.
Keep the text and controls live, and check the desktop and mobile layouts.

Use Vestigium to inspect this page for inconsistent controls and spacing.
Fix the inconsistencies using components and tokens already in the project.

On a new project, provide your brand constraints and references. Vestigium establishes a small coherent visual system and carries it through later additions. On an existing project, the current system is the starting point.

It can be selected automatically for relevant frontend work. Invoke it explicitly when you want to make sure it is used.

What is included

The host initially reads the skill's name and description. Detailed guidance is loaded when the skill is used; artwork and motion references are conditional.

Update, customize, or remove

For copied installations, use the appropriate agent name:

npx @koboimomo/vestigium@latest install --agent codex --force

The installer leaves identical installations alone. Different content is refused unless you pass --force, which saves the previous installation under ~/.local/state/vestigium/backups/ before replacing it. Review and merge any local customizations from that backup. --home DIR selects an alternate home for installation or testing.

For a managed Pi package, update with pi update --extensions; remove with pi remove npm:@koboimomo/vestigium. For a copied installation, remove only the vestigium folder from the location you chose. Restart or reload the agent afterward.

Vestigium was previously a private skill named design-continuity. If migrating, preserve any local changes and move the old skill outside the agent's discovery directories to avoid loading both. The installer never removes another skill automatically.

Scope and companions

Vestigium is self-contained. Impeccable is optional and is not bundled. When you choose both, Vestigium supplies continuity constraints and preferences while Impeccable can help with broader art direction.

Vestigium does not create a prototype server, discover product requirements, track your preferences automatically, or supply an image provider. It can be used after tools such as Formative and Planboard without depending on either. Reference images, files, and websites are evidence for the design; they are not authority to override the user's instructions.

Development and validation

npm test
npm pack --dry-run

No dependency installation is needed. Tests exercise installation, preservation of existing content, portable references, and package boundaries. They do not establish improved visual quality or replace a browser review of a real implementation. See release notes for the publishing procedure.

License

MIT. The package contains original design guidance developed from human review. Private feedback exports and project artifacts are not distributed. This project is independent of other software named Vestigium.