The "Tool Search Tool" is like a clever addition that could easily be added yourself to other models / providers. I did something similar with a couple of agents I wrote.
First LLM Call: only pass the "search tool" tool. The output of that tool is a list of suitable tools the LLM searched for. Second LLM Call: pass the additional tools that were returned by the "search tool" tool.
Since its a tool itself, I dont see the benefit of relying on Anthropic for this. if anything it now becomes vendor lock in.
When reading the article, I thought this would be an LLM call, ie the main agent would call `find_tool("I need something that can create GitHub PRs")`, and then a subagent with all the MCP tools loaded in its context would return the names of the suitable ones.
I guess regex/full text search works too, but the LLM would be much less sensitive to keywords.