Custom agents using the low level completion APIs tend to outperform these generic tools, especially when you are working with complex problems.

It's hard to beat domain specific code. I can avoid massive prompts and token bloat if my execution environment, tools and error feedback provide effectively the same constraints.

If I had to pick only one tool for a generic agent to use, it would definitely be ExecuteSqlQuery (or a superset like ExecuteShell). If you gave me an agent framework and this is all it could do, I'd probably be ok for quite a while. SQL can absorb the domain specific concerns quite well. Consider that tool definitions also consume tokens.