Anthropic Just Revealed 5 New Rules for Prompting Claude 5 Models

Anthropic just put out five official guides on how to use Claude, and a lot of what worked before is now either costing you more or slowing you down. And that includes long list of rules, examples pasted in, loading every file up front, using max effort for everything, and building a team of agents. This is all advice that we've

been seeing online up until this moment. And Anthropic did it themselves first. They deleted over 80% of the system prompt in Claude code, and their coding tests didn't get any worse. So, I read all five guides and pulled out the rules that actually matter. And to show you, I'm going to take one real Claude setup

that breaks every one of them, and then by the end of this video, we'll have fixed that one guide at a time so that you can do the exact same thing to your setup. And if you're new here, my name is Bart, and I build with Claude every single day. So, if you want to get more

videos on how to get the best out of your Claude setup, make sure you hit the subscribe button below. So, the setup is a Monday client report. Someone at a small agency takes last week's numbers, which is a spreadsheet export and a few notes, and gets Claude to turn them into a one-page report and a draft email.

It's got a Claude.md file of about 250 lines, and a report skill of about 400 lines with a style guide, a glossary, and three old reports pasted in. Everything runs on max effort, and there are four agents: a data puller, an analyst, a writer, and a checker, all handing notes to each other. Each of

those choices make sense once, but on the newest models, every one of them is actually costing the setup something. The first guide is the prompting guide for Opus 5.5. Near the top, it says your Opus 5 prompts should perform well without changes, and that the Opus 5 guide is still a reasonable starting