How to verify if the datadog agent is installed?

How can I tell if the datadog agent is installed? I’m running into an issue where no apdex metrics are available (even though latency and error metrics are), and I’m wondering if it’s an issue with the agent setup. My service repo does not have a datadog.yaml file, but I do see the service in the APM Service map and we are getting traces.

Hi, if you’d just like to see if DD Agent is installed you can run a status command outlined in the below doc:
https://docs.datadoghq.com/agent/guide/agent-commands/?tab=agentv6v7#agent-information