I find the automatic tool installation one of the most compelling features on Jenkins. But I think it lacks key management features. I started off writing an issue for detecting when to reinstall, which led to deleting installs from all nodes when the tool configuration is deleted, which led to wanting an option to manually delete a tool from individual nodes, which led to needing a UI that shows which tools are installed on a node, etc.

• A new http://<server>/tool/tool - list view of all agents with tool installed, checkbox next to each agent and button to uninstall from selected agents
• Add list of installed tools on http://<server>/computer/<agent>. I'm on the fence about having option to uninstall from this page of adding that to http://<server>/computer/<agent>/configure
• After removing under Manage Jenkins > Global Tool Configuration the tool should be removed from all connected agents
• From within Manage Jenkins > Global Tool Configuration each configure installation (ie sibling to each Delete tool** button) should be a button to see all installations of that tool 
• Detection of when the installed tool needs to be reinstalled
  • eg 32 bit JDK installed because agent was running under 32 bit JVM at the time of the installation, then agent is restarted with 64 bit JVM. The JDK install should be replaced with the 64 bit version.
  • eg Tools installed by extracted a zip/tar.gz from a remote URL detect when the zip/tar.gz has been updated (by checksum or date/size) and reinstall