[FEATURE] Allow for customizable tools parameters/description

[SpaYco]

Scope check

• This is core LLM communication (not application logic)
• This benefits most users (not just my use case)
• This can't be solved in application code with current RubyLLM
• I read the Contributing Guide

Due diligence

• I searched existing issues
• I checked the documentation

What problem does this solve?

This would allow you to add parameters on initialization, would be useful for similar tools with different parameters or for customizable tools by users/customers of your app.

Proposed solution

Should be as simple as doing this:

ruby_llm/lib/ruby_llm/tool.rb

Lines 58 to 64 in 96d06c4

	def description
	self.class.description
	end
	def parameters
	self.class.parameters
	end

 def description 
   @description || self.class.description 
 end 
  
 def parameters 
   @parameters || self.class.parameters 
 end 

Then if you add @parameters or @description on initialization, it will use the instance variables instead

This would keep the current way of creating the classes but allows for better custom parameters/descriptions without cluttering the codebase.

Another idea is to join the class variable with the instance variable.

Why this belongs in RubyLLM

Doing this in application code can cause more uncertainty and instability because a change to the core RubyLLM gem could break custom implementations. Officially supporting this method ensures its stability and long-term compatibility.

[SpaYco]

After implementing something like this locally, I discovered that the method name in RubyLLM::Tool can give out the same name if you use the same tool class multiple times, this is probably an issue now even if you use it for things other than custom parameters, like the custom initialization written in the official docs, so if this gets accepted and implemented, we need to either make it use a unique name every time, or have clear documentation about this issue.

only breaking change with having unique name is if you used the current (broken) functionality to replace the same tool, without using the replace parameter

[SpaYco]

I am happy to implement this, just needs the approval from the maintainers that it will be merged.