I have a blog post here that has an example of dynamically changing the tool list- https://jonwoodlief.com/rest3-mcp.html.

In this situation, I would have a tool called "request ability to edit GLTF". I This would trigger an addition to the tool list specifically for your desired GLTF. The model would send the "tool list changed' notification and now the LLM would have access.

If you want to do it without the tool list changed notification ability, I'd have two tools, get schema for GLTF, and edit GLTF with schema. If you note that the get schema is a dependency for edit, the LLM could probably plumb that together on it's own fairly well

You could probably also support this workflow using sampling.

do any of the clients support this? I have some dynamic mcps and it doesn't seem like claude.ai supports for example.