Countable:
* When referring to individual tools, it is countable:
* "He has a set of tools in his toolbox." (Each tool is distinct.)
* "I need to buy a new tool for my project." (One specific tool.)
* When referring to different types of tools:
* "There are many different tools used in construction." (Each type of tool is distinct.)
Uncountable:
* When referring to the general concept of tools:
* "Education is a powerful tool for change." (Tools as a general concept.)
* "The company provides its employees with the necessary tools to succeed." (Tools as a collective concept.)
In summary:
* Countable: individual tools, types of tools
* Uncountable: the general concept of tools
The context will determine whether "tool" is countable or uncountable.