> bash-only tooling has higher success for bash-capable models, compared to using predefined tools for models that aren't good at bash?

No. The conclusion is that:

bash-capable models + bash-only tools > bash-capable models + predefined tools

In other words, MCP was just a bunch of bullshit that maybe helped a little bit until the models got good at bash, and now it's basically useless.

bash scripts, famously the last word in software engineering. all these castles of sand we've built atop the beautiful, perfect, timeless Bourne Again SHell. all for naught. fools!