I would like to communicate with prefect outside of python. Are there graphql definition files I can use to generate clients?

AFAIK the GraphQL schema can be retrieved from a running server, you just need to query for it. Hasura generates a bunch of the schema. You can see our custom schema at https://github.com/PrefectHQ/server/tree/master/src/prefect_server/graphql/schema but that will exclude the many Hasura queries

what headers would i need to pass to authenticate with my api key?

From the

client

code

if token:
            headers["Authorization"] = "Bearer {}".format(token)

        if self.api_key and self._tenant_id:
            # Attach a tenant id to the headers if using an API key since it can be
            # used accross tenants. API tokens cannot and do not need this header.
            headers["X-PREFECT-TENANT-ID"] = self._tenant_id

hmmmm that doesnt seem to work