[Feature Request] Support conditional tool calling

[lightaime]

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Motivation

Supporting conditional tool calling means we can build a FSM with state and active_tools or a simple DAG for active_tools. This will be very helpful for workforce.

Solution

No response

Alternatives

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Additional context

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[Wendong-Fan]

research topic, would @yiyiyi0817 and @WHALEEYE be interested in this one?