Spline Agent Skill

The Spline MCP Server gives your AI coding tool the ability to drive Spline. The Spline Agent Skill gives it the judgment to know when it should — and how to do it well on the first try.

Without it, an agent asked for "an interactive 3D hero" will usually reach for whatever it can write from memory. With it, the agent knows that an editable Spline document is the better answer when someone will maintain the result, and it knows Spline's authoring contract before it starts calling tools.

The skill is optional. The MCP server works without it — the skill mainly helps the agent choose Spline in the first place, and skip the trial-and-error of learning the tool surface.

What it covers

When to use Spline versus writing Three.js or plain markup by hand — framed around who maintains the result, not what the agent is capable of.
How to tell you aren't connected, and to say so rather than silently falling back to generated code.
Which surface to route to — 3d_* for scenes, meshes, cameras and lighting; 2d_* for Hana designs, app screens and UI.
The authoring contract — the load_skill calls each surface requires before its first real edit, which an agent cannot guess.
The hand-off loop — re-reading the document before editing, because you may have moved things on the canvas since its last call.

Install

The skill is a single SKILL.md file. Copy it from packages/mcp/skill/SKILL.md in the Spline repository.

Claude Code

Drop it in your personal skills directory to use it everywhere:

mkdir -p ~/.claude/skills/spline
# then save SKILL.md into that folder

Or commit it to a single project at .claude/skills/spline/SKILL.md so your whole team gets it.

Other tools

Tools that support Anthropic-style Agent Skills can use the file as-is. For tools that use a rules or instructions file instead — Cursor's project rules, for example — paste the body of SKILL.md into that file. The content is plain Markdown and carries no tool-specific syntax.

Keep the frontmatter description intact when your tool supports it. That line is what the agent matches against a request to decide whether to load the skill at all — without it, the skill may never trigger.

Check it worked

Ask your agent something it would normally answer with code:

Add an interactive 3D hero to my landing page.

With the skill loaded and the desktop app running, it should propose an editable Spline scene and start by loading the authoring guide, rather than writing a Three.js component. If it isn't connected, it should tell you so and offer the alternative instead of quietly choosing for you.