Allow composing Agents as Tools via ComponentTool (input = UserMessage)

[tommyjs007]

Summary

At the moment, it’s difficult to integrate one Agent as a Tool for another Agent, because agent inputs are based on lists of UserMessage objects rather than simple structured parameters. This makes nested or modular agent setups cumbersome and requires custom wrappers or adapters.

Proposal

Extend the existing ComponentTool so it can accept an Agent as its component argument.
This would allow developers to compose agents naturally using the same ComponentTool pattern already used for other components.

producer_info_tool = ComponentTool(
        component=producer_info_agent,
        description="Use this tool to find producer information by passing producer's name and it's country",
        name="producer_info_tool"
)

[sjrl]

Hey @tommyjs007 thanks for raising! I did want to point you towards this tutorial Tutorial: Creating a Multi-Agent System with Haystack and specifically this section which shows exactly how to pass Agent into a ComponentTool.

Basically it should just work. The only recommendation I'd make for your set up is to also include outputs_to_string={"source": "last_message"}, to your ComponentTool definition so only the last assistant message is sent back up to the top-level agent instead of the full history of messages.

If you'd like to see a more complicated example that my colleague @vblagoje created check out his Itinerary Planner Agent here where he also uses Agent as a ComponentTool

[tommyjs007]

Hey @tommyjs007 thanks for raising! I did want to point you towards this tutorial Tutorial: Creating a Multi-Agent System with Haystack and specifically this section which shows exactly how to pass Agent into a ComponentTool.

Basically it should just work. The only recommendation I'd make for your set up is to also include outputs_to_string={"source": "last_message"}, to your ComponentTool definition so only the last assistant message is sent back up to the top-level agent instead of the full history of messages.

If you'd like to see a more complicated example that my colleague @vblagoje created check out his Itinerary Planner Agent here where he also uses Agent as a ComponentTool

Oh yes, you're right. Thanks for the help. Will close this issue