Tool Best Practice: Assign to Agent or Task?

General
1

Hi everyone!

I’m diving deeper into the use of Tools within CrewAI and a question came to mind:
Is it better to assign tools directly to Agents or pass them as resources to Tasks?

I’ve seen that CrewAI supports both approaches, but it’s not clear to me when one is more appropriate than the other, or what the practical implications are.

So I’m wondering:

  • What are the best practices recommended by the CrewAI team or experienced users?
  • What are the key differences between assigning a tool at the agent level vs. the task level?
  • Are there specific use cases where one strategy is clearly better than the other?

Thanks in advance for any suggestions or insights!

2

Simone,

So, in the current setup, if you take a peek at the docstrings for Agent and Task, you’ll find:

  • Agent.tools: Tools at agents disposal.
  • Task.tools: List of tools/resources limited for task execution.

This kinda suggests that Task.tools are meant to be like a “filtered down” version of Agent.tools.

But, when you get down to the nitty-gritty of how it’s implemented, that’s not strictly enforced. If you set Agent.tools but leave Task.tools empty, then Task.tools just inherits all the tools from the Agent. On the other hand, if you do define Task.tools, then those are the tools the task will use, no matter what you put in Agent.tools – heck, it doesn’t even matter if you left Agent.tools completely blank! So, practically speaking, either way works.

Personally, I lean towards what the documentation hints at and try to stick to that approach. It just makes more sense to me. Think of it like this: I hire a contractor (our Agent) to renovate my house, and I hand him a full toolbox. Then, when he’s specifically going to change a faucet (a Task), I wouldn’t want him to have the jackhammer readily available – just to be on the safe side, y’know? Of course, I wouldn’t actually need to do that with a real contractor, assuming he’s a pro at his job. But with LLMs, it makes sense to restrict their toolkit for each task. Don’t forget, we’re dealing with LLMs, and LLMs are primarily stochastic, meaning randomness is part of their DNA. If you really don’t want it to push a certain button, it’s probably best not to even let it see that button.

Let’s see what other folks here think about it!

1 Like
3

So if I understood correctly, the only difference lies in what tools the agents can use to execute the tasks.
If I assign 2 tools to the agent, it will have access to both tools regardless of which task it’s performing,
whereas if I assign a specific tool only to a specific task, the agent will only be able to use the tools assigned to that particular task it’s executing, right?

4

Simone, I took a look at the part of the code that handles this. And here’s the deal:

  • If you explicitly provide tools to the Task: The task will keep only the tools you gave it. Agent.tools are NOT automatically added here.
  • If you DO NOT provide tools to the Task: In this case, Task.tools will be populated with Agent.tools.

So effectively, Task.tools takes precedence. Now, to answer your last question more directly:

  • If you assign 2 tools to the agent (Agent.tools = [ToolA, ToolB]) AND you don’t specify tools for a Task, then yes, for that task, the agent will use [ToolA, ToolB] (because task.tools will inherit them at initialization).
  • If you assign a specific tool only to a specific task (Task.tools = [ToolC]), then yes, the agent will only be able to use [ToolC] for that particular task’s execution, regardless of what Agent.tools contains.
5

In conclusion, using the contractor example, it’s like giving him a toolbox: if I don’t specify which tool to use to change a faucet, he’ll choose one from the toolbox I gave him (a tool assigned to the agent but not to the task).
On the other hand, if I give him the toolbox and say “use tool A to change the faucet” (which could even be outside the toolbox), then he’ll ignore all other tools and use the one I specified (tools assigned to both the agent and the task).
Assigning a tool only to a task without setting anything for the agent is like handing him a specific tool and saying “use this tool to replace the faucet.”

1 Like
6

Yep, you totally got it!