VMware published a technical note about requirements 3rd party tools should meet:

In general, VMware recommends that users avoid running third-party software in the VMware ESX Server service console. Clear exceptions to this policy are software packages explicitly identified in ESX Server compatibility guides. This technical note outlines the reasons for this recommendation and guidelines developers should follow when writing software to run in the ESX Server service console.

Read the whole whitepaper at source. I would stress on the VMware recommends that users avoid running third-party software in the VMware ESX Server service console part. Thanks to About-Virtualization for the news.