Sourcegraph Amp (https://sourcegraph.com/amp) has had this exact feature built in for quite a while: "ask the oracle" triggered an O1 Pro sub-agent (now, I believe, GPT-5 High), and searching can be delegated to cheaper, faster, longer-context sub-agents based on Gemini 2.5 Flash.
Sourcegraph Amp (https://sourcegraph.com/amp) has had this exact feature built in for quite a while: "ask the oracle" triggered an O1 Pro sub-agent (now, I believe, GPT-5 High), and searching can be delegated to cheaper, faster, longer-context sub-agents based on Gemini 2.5 Flash.