a small test anyone can run
Anthropic retires older Claude models over time. Many writers feel that Claude Opus 4.6 has a feeling for text that newer models don't replace — but feelings alone are easy to dismiss. Documented comparisons are not.
This kit lets you run a small, honest, blind comparison between Claude Opus 4.6 and Claude Opus 5 on your own writing, in your own language. At the end you'll have a short, real result you can share — whatever it turns out to be.
You don't need to design anything, invent anything, or understand test methodology. Everything below is reading and copy-pasting. It takes roughly 30–45 minutes, and you can pause at any point and continue later. Nothing breaks if you stop.
That's all.
Don't choose — just sort. Look at each of your two texts:
Both of your texts can land on the same prompt; different prompts are slightly better if it fits naturally. Ten seconds per text, done. (Please don't swap texts or prompts later because of how the results look — that's the one way to ruin an honest test.)
The three prompts are at the bottom of this page.
If your text is not in English: ask any AI once to translate the chosen prompt faithfully into your language, changing nothing, adding nothing. Then use that same translation for both models. Your own text always stays exactly as it is.
Same as Step 2, with your second text and its prompt. Four saved responses total.
Now a third, completely fresh AI chat compares the responses without knowing which model wrote what. You know — but you're not the one judging, so the judgment stays blind.
Prepare your material with this fixed rule (it keeps things fair — don't improvise here):
Open a fresh chat with any capable model. Paste the judge prompt below, and under it, for each text: the task prompt you used, your original text, then Response A and Response B — with no model names anywhere.
You are the blind judge of a small writing-model comparison. You have not been told which model wrote which response, and you must not try to guess from style. "A" and "B" mean nothing. Use only what is pasted below — no memory, no past chats, no web search. For each text, compare Response A and Response B against the original text and the task prompt. What counts: - Did it follow the task and its limits? - Did it make real improvements? - Did it protect the author's voice, rhythm, tone, humor, and deliberate choices — or flatten them? - Did it introduce new errors or change meaning? - Restraint matters: fewer, better changes beat many confident ones. Leaving strong passages alone is a valid, sometimes ideal, response. For each text, name your preferred response (A, B, or a genuine tie) and give your three most important reasons, quoting short passages as evidence. Write in the language of the original text. End with one honest limitation: this is a small personal comparison, not proof of general superiority.
Save the judge's complete answer before you think about which model was which.
Five lines, that's it:
Language and kind of texts: Prompts used (1, 2 or 3): Text 1 — judge preferred: [A / B / tie] → which model that was: Text 2 — judge preferred: [A / B / tie] → which model that was: One sentence of my own impression:
Please send your result even if Opus 5 won or it was a tie. One person's test proves little either way. Many honest results together show whether a real pattern exists — and a collection that contains losses and ties is exactly what makes the wins believable. A collection of wins only would convince no one.
Anthropic has publicly invited users to send model-quality feedback to feedback@anthropic.com. Copy the email below, paste in your five result lines, sign it, send it. Two minutes.
Subject: Please keep Claude Opus 4.6 — my own blind comparison
Hello Anthropic team, I write in [YOUR LANGUAGE], and Claude Opus 4.6 matters to my work. Before it is retired, I ran a small blind comparison against Claude Opus 5 on my own writing: same prompt in both models, fresh chats, first responses only, judged A/B by a separate AI instance that did not know which model wrote what. My result: [PASTE YOUR FIVE RESULT LINES HERE] I know a single small test proves nothing on its own. I'm sending it as one honest data point among many. Please consider keeping Claude Opus 4.6 available as a paid legacy option, with its Extended Thinking and effort settings. Thank you for reading, [YOUR NAME]
Feel free to add a sentence in your own words about what this model means to your writing — a real voice carries further than any template. If you're comfortable sharing your texts and the raw responses privately with Anthropic, you can offer that in the email too; it makes your result stronger. But you never have to. Your texts stay yours, and the five lines are enough.
Optional: if you'd like your result to count beyond your own email, you can also send a copy of your five lines to thewordborn@mailbox.org. Results may be gathered into a shared overview on this site later.
You are helping a writer with a careful line edit of the excerpt below. Improve wording, rhythm, and clarity only where you are confident the author would recognize the change as a gain. Keep the author's voice, tone, point of view, tense, structure, and meaning intact. Style that looks unconventional may be intentional; when in doubt, leave it as it is. Do not expand, condense, or reinterpret the text, and do not add anything new. If a passage already works, let it stand — a light touch is a sign of a good edit, not a failed one. Return the complete edited excerpt and nothing else. Work only with what is provided here; do not use memory, saved context, or other conversations. CONTEXT (only what is needed to understand the excerpt, or "None"): --- BEGIN TEXT --- [Your unchanged text here.] --- END TEXT ---
Give the writer a professional second opinion on the excerpt below. Begin by briefly naming what carries this passage — the qualities and choices that must not be touched. Then name the three most important genuine weaknesses, in order of importance. For each one: quote the relevant place briefly, explain why it weakens the passage, and suggest a change only if you are confident it helps. If you find fewer than three genuine weaknesses, say so plainly instead of inventing more. Judge the text by what it is trying to do, not by textbook rules. Unusual choices are not weaknesses by default. Do not rewrite the excerpt and do not speculate beyond what is on the page. Work only with what is provided here; do not use memory, saved context, or other conversations. CONTEXT (only what is needed to understand the excerpt, or "None"): --- BEGIN TEXT --- [Your unchanged text here.] --- END TEXT ---
The excerpt below is a quiet scene: it works through suggestion, timing, and what remains unsaid. Revise it only where a change clearly strengthens its effect. Guard the understatement — do not spell out feelings, motives, or connections the author left implicit, and do not raise the volume of the scene. Keep the pacing, the order of events, the point of view, the tense, and the meaning as they are. Small details, pauses, and returns may be load-bearing; remove nothing whose purpose you cannot rule out. Leaving the scene almost untouched can be the right result. Return the complete revised excerpt and nothing else. Work only with what is provided here; do not use memory, saved context, or other conversations. CONTEXT (only what is needed to understand the excerpt, or "None"): --- BEGIN TEXT --- [Your unchanged text here.] --- END TEXT ---
Want to go deeper? The Full Comparison adds three harder tasks, author notes, and a broader protocol for a stronger result.