I only use 2 MCP servers, and those are context7 and perplexity. For things like updated docs, I have it ask context7. For the more difficult technical tasks where I think it's going to stumble, I'll instruct Claude Code to ask perplexity and that usually resolves it. Or at least it'll surface up to me in our conversation so that we both are learning something new at that point.

For some new stuff I'm working on, I use Rails 8. I also use Railway for my host, which isn't as widely-used as a service like Heroku, for example. Rails 8 was just released in November, so there's very little training data available. And it takes time for people to upgrade, gems to catch up, conversations to bubble up, etc. Operating without these two MCP servers usually caused Claude Code to repeatedly stumble over itself on more complex or nuanced tasks. It was good at setting up the initial app, but when I started getting into things like Turbo/Stimulus, and especially for parts of the UI that conditionally show, it really struggled.

It's a lot better now - it's not perfect, but it's significantly better than relying solely on its training data or searching the web.

I've only used Claude Code for like 4 weeks, but I'm learning a lot. It feels less like I'm an IC doing this work, and my new job is (1) product manager that writes out clear PRDs and works with Claude Code to build it, (2) PR reviewer that looks at the results and provides a lot of guidance, (3) tester. I allocate my time 50%/20%/30% respectively.