This may be a premature optimization. There are only around 150 questions between the two tags, so it's not a large statistical universe to work with. It may take some time to see how the community tags (or mistags) questions with various tags, and to learn what new tags people with the tag creation privilege will apply to the knowledge domain.
Once the question pool is larger, it will be much easier to retrofit the tags with extensional definitions.
It's still worthwhile to try and differentiate the tags, although I see it as a continuous process that will need to be revisited. Here are my current thoughts on the matter.
The tools tag is really a superset of the various devices and implements used to manage a project. Sub-categories obviously include hardware, software, and communications devices, but also include less obvious categories such as reporting mechanisms and coordinating tools (e.g. a physical kanban).
Should implements such as a chess clock used for code-pairing be tagged as tools? Sure. How about a Bic pen used to take notes during a status meeting? Probably not.
It seems to me that the dividing line between tools and something out of scope is whether it visibly supports a defined project management process. Based on that definition, software becomes the 800-pound gorilla in the room, but still allows for existence of physical and mechanical tools.
Of course, if 99.999% of the tools are software, is it really useful to differentiate for the edge cases? Probably not. The percentage of non-software tools-related questions is bound to be quite small, except when they are narrowly focused on a particular project management practice such as Kanban or XP coaching.
The real issue, in my opinion, is the way people use the word "tool." In common parlance, tools are often proxies for "How do I solve my process problem?" If the answer is not obvious on a process level...well, there must be a tool for that!
Rather than create an arbitrary distinction between tools and pm-software, it might be better to create less culturally-overloaded tags. For example, someone might propose framework-support-software or resource-estimator.
The superset tag could then be renamed to using-project-management-tools or using-methodology-tools to make it clear that the topics are about using or implementing specific tools, rather than for shopping list recommendations. This won't actually stop people from misusing various tags, but could conceivably cut down on the noise.