get_custom_event_definitions
Every distinct custom event name the store has fired, with totals, first and last seen, and a sample of the property keys observed.
When to use it
First, before querying custom events at all. It is how you discover what exists rather than guessing at names.
Ask for it like this
You do not name the tool. These are questions that make an assistant reach for it:
What custom events does my store fire?
Parameters
This tool takes no parameters of its own.
Shared parameters it accepts
None. This tool is not date-scoped — it reports current state rather than a window.
Every tool also accepts merchantId, which resolves from your connection. You never pass it.
What comes back
JSON. These are the top-level keys; date-scoped tools additionally carry a _meta block with the server date and the data coverage envelope.
definitions
Per event name: total occurrences, first and last seen, and observed property keys.