Hi i have multiple agents running on Prefect. Incase any agent goes down (turns yellow/red) can we get slack alert to get notified?

If you are on Prefect Cloud, yes - check Agent SLA Automations here

no its personal server

we don't have any such automation for Server to get notified if the agent process goes down - in that case, you would need to implement monitoring on the infrastructure level, e.g. tracking logs and metrics on your agent's VM and sending something like Grafana alert if the agent no longer emits health checks or agent process dies