🧭Architektur: drei Wege zum selben Ziel

partial interface Document {
  [SecureContext, SameObject] readonly attribute ModelContext modelContext;
};

[Exposed=Window, SecureContext]
interface ModelContext : EventTarget {
  Promise<undefined> registerTool(ModelContextTool tool, optional ModelContextRegisterToolOptions options = {});
  Promise<sequence<RegisteredTool>> getTools(optional ModelContextGetToolOptions options = {});
  Promise<DOMString> executeTool(RegisteredTool tool, optional any inputObject, optional ModelContextExecuteToolOptions options = {});
  attribute EventHandler ontoolchange;
  attribute EventHandler ontoolactivated;
  attribute EventHandler ontoolcancel;
};

dictionary ModelContextTool {
  required DOMString name;         // 1–128 Zeichen: A–Z a–z 0–9 _ - .
  USVString title;
  required DOMString description;  // darf nicht leer sein
  object inputSchema;              // JSON Schema, muss serialisierbar sein
  required ToolExecuteCallback execute;
  ToolAnnotations annotations;
};

dictionary ModelContextRegisterToolOptions {
  sequence<USVString> exposedTo;
  AbortSignal signal;              // abort() meldet das Tool ab
};