Azure Build agent cant´t find class library referance

around this issue The problem was simple - I did not see where the Capabilities tab was. IMHO Requests and Capabilities are not easily discoverable. I saw it and I set the two variables to true and it started to work even though I did not know for sure if true is the right value.
Another problem was that NVM SYMLINK was not working as expected and the build agent could not find node.exe at all. It was not in the PATH at all. I uninstalled nvm and used only node 8.1.2 with npm 5 in order to make it run.

I wish this helpful for you Yes. As long as the machine can establish a network route to dev.azure.com, it'll work fine.
If you need your VMs to have access to on-prem resources or be joined to your internal domain, you'll have to establish a VPN connection.

it fixes the issue The build succeeded webhook always returns a "queue" property which specifies the worker which handled the build. Which job of the build has run on which worker (at least the worker name) is visible if you access the timeline for the build.

I hope this helps . Generally speaking in 99,99% cases keeping a direct reference to the project is not a good idea. You can end up with really unmaintainable CI/CD logic and/or with dll versions mismatches during deployments. Actually I am an Architect in the project where I tried to fix that issue by migrating all dependencies to the NuGet server.
Azure Artifacts

it fixes the issue I'm note sure if this package contains the VS extension targets you are looking for. But by including a reference to it and restoring it you may be able to get the targets onto the agent and get your build working.
Additionally, you can probably create a package containing the targets you need with NuGet, publish it to a package repository and then restore that onto your agent during build time.