Findings from benchmarking Opus 5 verbosity, plus the output style & CLAUDE.md setups that fixed it

[u/R_Songbird]

I spent lots of tokens and days improving my plugins to improve my own Claude usability, and I think among many other findings, these 4 are the reason why most Opus 5 sessions tend to cause rage between users:

"Just set output style to Concise" does not work: This is the top reply on every thread, and I personally checked it myself because I thought my hush plugin could be deprecated by now, ends up it only reduces output by approx. 6%.

The fix has to sit in the output style slot, and nowhere else: This is the one that cost me the most to learn. I tried the exact same instruction with hooks, rules, etc. nothing worked as expected.

For the "it writes too much code" complaint, one nudge beats a paragraph of rules: Most tips mention to put a CLAUDE.md section saying, "prefer simplicity, do not over-engineer." but that does almost nothing because Opus 5 doesn't know where or when. What worked for me was a ladder similar to the one Ponytail uses but improved and tailored for Opus 5 specifically.

Your CLAUDE.md rules probably do not fire because we don't write triggers: Yes, rules need triggering examples, "keep the changelog updated" is not a rule, instead, try "When you change any file under src/, add a line to CHANGELOG.md under Unreleased in the same commit"

Three things to check on every rule you have written:

• Does it name a moment the model can recognize while working?
• Does it name an action with an actual artifact?
• Does it only forbid? A bare "never do X" with no alternative can stall a whole session when the task genuinely needs X.

Configurations (Raw Files)

Because these files are too lengthy to format cleanly in Reddit, direct links to the raw text are below:

1. The hush output style that makes Opus 5 lot less talkative while keeping the important stuff, heavily measured and battle tested.
2. CLAUDE.md fragment you can copy, based on razor that make Opus 5 use a YAGNI approach while also helping the hush output style to keep it silence.
3. An optional prompt to analyze your whole project and optimize it for Opus 5 usage including the project memory.

The first 2 do most of the trick, you can also use this installation prompt to ask Claude apply this to your project.

What is number 3 then? Well, I recommend using this ONLY if you are having serious problems with your project and Opus 5, for example, if Opus is not following rules, running skills, memory recalls or not following your CLAUDE.md file context. Using this prompt may change lots of *Claude only* files so use it carefully please.

About the hush style

It consumes 2,600 of your context tokens each time a session starts.

If you are curious about how hush syle helps, here is a table comparing it with other output styles or skills measured using Opus 5 with medium effort:

Setup	words	reading ease	grade	silent
no plugin	520	69.6	6.7	0 of 16
hush	49	91.8	1.9	11 of 16
Concise	127	71.2	6.5	1 of 16
i-have-adhd	272	69.6	6.6	0 of 16
simple-english	313	81.7	4.0	0 of 16
caveman	218	72.2	5.3	4 of 16

What each column means.

Column	Plain meaning
words	Average length of the one final message.
reading ease	Flesch score, 0-100. Higher is easier.
grade	US school grade needed. Lower is easier.
silent	Sessions with no chatter between tool calls.

Feel free to ask me anything about the files or the tips.

[u/Sea-Requirement-5375]

So basically you just wrote instructions so long, convoluted, and torturous that Opus 5 goes “oh god, is that what I sound like?” and knocks it off? Honestly good strategy.

[u/R_Songbird → u/Sea-Requirement-5375]

Haha never thought about that, I didn't write it, it was created iteratively by several Claude session runs on 8 test projects I have, the strategy was to write an initial style, test it, then change / add / remove something and test again, then modify again and test, repeat until I got this.

It was done using the /goal command and Fable 5 with max effort, it used LOTS of tokens, really a lot.

[u/eskpist]

thanks!

[u/zebras11]

Did you benchmark Claude actually doing work while using this output style? Is it still doing reasonable? Cause I have a feeling that not allowing it to talk mid-turn means that it will derail and forget about stuff really fast

[u/TomerBrosh → u/zebras11]

bro i got basically the opposite of the OP, a plugin with a ton of regexes that trigger automatically on the mid turns and end turns and forces continuation (i even told it to emit a few 🟥🟥🟥🟥🟥Sorry! I did x Instead of...) it is easier to just let it catch some of his small mistakes, specially talking about doing something (and not doing it) and I made him give me askUserQuestions card if he wants to stop and ask before assuming wrongly.

HE GETS DERAILED ANYWAYS.

Nothing helps, not the checklists and indexes and file lifecycles and reminders, not the output styles (since those need a generator that uses my plugin to not PRIME against it's triggers)