We didn't include it in our initial explainer since these are things the author ca already do, however, having an API to list out the registered tools and be able to execute them by name and argument dictionary would be useful for external agents (e.g. provided via extensions or third-party libraries).

Perhaps something like:

window.agent.tools[0];

Would return an object like:

{
    name: "add-todo",
    description: "Add a new todo item to the list",
    inputSchema: {
        type: "object",
        properties: {
            text: { type: "string", description: "The text of the todo item" }
        },
        required: ["text"]
    },
    execute: <...function object...>
}

Which a third-party agent could use via await window.agent.tools[0].execute({text: "foo"})