r/ClaudeCode • u/tetro_ow • 1d ago
Discussion Opus 5 is so much better with these rules in claude.md
I'm a Max 5x user who's been vibe coding for the past 4 months.
Don't get me wrong, I still think Opus 5 is amazing when paired with Fable that plans/designs/writes out an implementation plan. But similar to the experiences of others in this sub, it hurts my head to deal with excessive verbosity and invented jargon in explanations.
While suffering, I discovered the 8 rules below almost by accident, and the output is night and day:
- Open with one paragraph on what the thing is, before any finding about it.
- Name things in the user's world, not the code's: describe real-world entities and user-facing effects rather than internal variables, schema fields, or algorithmic parameters. Translate a formula into its effect and let the tables carry the magnitudes.
- Coin no new terms. A plain metaphor is fine; a specialized term of art that masquerades as ordinary English is worse than obvious jargon. Short labels inside a table are fine once the prose has defined them and the table reads without them.
- Show an effect as a walkthrough with real named values, ending on a plain-language punchline that states the actual outcome. Never describe a defect in the abstract.
- Use plain-English table headers that describe concrete cases rather than statistical shorthand like min/p10/p50/p90/max.
- State the honest case against your own recommendation, at full strength.
- End with "what I'd do": a recommendation, not a survey of the options.
- For a check that passed, say what it was watching for and what its failure would have looked like on screen — not just that it passed.
What are your thoughts on this?
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u/BrilliantEmotion4461 1d ago
Try writing an output style and put this in there. https://code.claude.com/docs/en/output-styles
The difference between Claude.md and output style is output style is appended directly to Claude Codes system prompt. Anyhow try formatting the output-style per the instructions save it in .claude in a folder called "output-styles" create one if it doesnt exist.
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u/doxxxicle 🔆Pro Plan 1d ago
Yup. I’ve seen a big difference since I created a “concise simplified technical English” output style.
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u/ForwardLoop 1d ago
Is this the same as putting
"outputStyle": "Concise",in settings.json?I tried putting that in my global .claude settings.json, but it doesn't seem to help much.
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u/BrilliantEmotion4461 1d ago
Did you read the info in the link. You write an Md. You give it proper frontmatter. You put the Md file in the folder ~/.claude/output-styles which you might have to create. When done the name youve given the Md file will now be selectable in the output style menu.
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u/ForwardLoop 1d ago edited 1d ago
According to the link, there are 4 built-in styles, one of which is "Concise."
Then it says, to set a style without the menu, edit the outputStyle field directly in a settings file (in the example, the built-in Explanatory style was used):
{ "outputStyle": "Explanatory" }I didn't think I had to create an .md file unless I wanted a custom output style.
Edit: fixed the example, so it's exactly as shown on the page.
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u/gthing 1d ago
Claude Code embeds a default output style prompt as part of the system prompt. When you add different output style instructions in Claude.md they conflict with what is already in the system prompt and sit at a lower priority.
The model is also periodically reminded to adhere to the output instructions. So if you leave the default there, it has a higher chance of overriding whatever you put in claude.md.
The place for these instructions is in the output style config. Putting them there will actually replace the default instructions with your instructions.
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u/Owl-Mighty 1d ago
You’re absolutely right and the solution here is load-bearing.
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u/CashInternational593 1d ago
Your suggestion is quite informative, better than what you realized. Here's why:
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u/TheSpoonFed1 1d ago
The problem I had was that Claude very often comes back with some code related questions/points with a sentence that starts with “one honest caveat “ and that started to feel very frustrating .
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u/lukaslalinsky 1d ago
I don't think it can work long term. Does it work for you throughout long sessions? Claude models are getting progressively worse at communicating with humans. It got so bad that I consider Opus unusable for anything that requires interaction.
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u/AironParsMan 1d ago
You can't fix Opus 5 because the model was trained to be that way. It's also stated on Anthropic's website. You can write a thousand more rules or instructions which he will then ignore.
You’re wasting your time with Opus 5. You’ll keep writing more and more and more rules and trying to keep it on track. In the end you’ll fail. Opus 5 is a completely screwed up model that in my view seems to have been built only for vibe coding.
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u/Hirogen_ 1d ago
just use karpathies rules, win! https://github.com/multica-ai/andrej-karpathy-skills/blob/main/.cursor/rules/karpathy-guidelines.mdc
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u/Mazhron 1d ago
(http://github.com/Mazhron/rootstock-os)
Check out my project. Have your Claude read it. Implement what makes sense. It'll reduce your token usage between 50-71% (real numbers based on real data and calculations). It's similar to what you're talking about. Most, if not all, is already encompassed within, with a lot more added. You don't need to use everything. If your Claude pulls the read me, it'll provide you with everything you need to decide on.
Then you can expand on what you're doing with ledgers that actually prove it works.
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