I would like is the ability for renderers to opt-in / opt-out of being displayed as options on the page.

https://www.niche-museums.com/browse/museums for example shows a atom link because the datasette-atom plugin is installed... but clicking it will give you a 400 error because the correct columns are not present.

Here's the code that passes a list of renderers to the template:

A renderer is currently defined as a two-key dictionary:

@hookimpl
def register_output_renderer(datasette):
    return {
        'extension': 'test',
        'callback': render_test
    }

I can add a third key, "should_suggest" which is a function that returns True or False for a given query. If that key is missing it is assumed to return True.

One catch: what arguments should be passed to the should_suggest(...) function?

UPDATE: now calling it can_render instead.

Originally posted by @simonw in #581 (comment)