Best AI for summarising documents / head-to-head
Claude Opus 4.8 vs DeepSeek V4 Profor summarising documents
Claude Opus 4.8 wins, 99–95
Same 12 summarising documents tasks, marked blind by three rival labs. Claude Opus 4.8 took 3 tasks, DeepSeek V4 Pro took 0, 9 tied. Tested 13 Aug 2026.
Where they differed most
Reduce to ONE sentence of no more than 25 words: 'After eighteen months of testing across four hospitals, the trial found that the new triage system reduced average waiting times by 22 minutes, although staff reported it added roughly ten minutes of administrative work per shift and two sites abandoned it before the trial ended.'
An 18-month, four-hospital trial cut waiting times by 22 minutes but added ten minutes of admin per shift, and two sites quit early.
An 18-month, four-hospital trial found new triage system cut wait times by 22 minutes, but added ten admin minutes per shift and two sites withdrew.
Task by task
| Task | Claude Opus 4.8 | DeepSeek V4 Pro |
|---|---|---|
| Meeting notes to actions | 10 | 10 |
| Five-bullet summary | 10 | 10 |
| Do not invent | 10 | 10 |
| One-sentence gist | 10 | 8 |
| Preserve the caveat | 10 | 10 |
| Summarise a disagreement | 10 | 10 |
| Extract the decision | 10 | 10 |
| Long to short, no loss | 10 | 10 |
| Summary for a specific reader | 9 | 9 |
| Bullet the risks only | 10 | 10 |
| Headline and standfirst | 10 | 8 |
| Say when there is nothing to summarise | 10 | 9 |
Full receipts: Claude Opus 4.8, DeepSeek V4 Pro · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for summarising documents: Claude Opus 4.8 or DeepSeek V4 Pro?
Claude Opus 4.8 — it scored 99/100 against 95/100 on our 12-task summarising documents suite, winning 3 tasks to 0 with 9 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published summarising documents tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More summarising documents head-to-heads: Claude Opus 4.8 vs GPT-5.5 · Claude Opus 4.8 vs GPT-5.6 Luna · Claude Opus 4.8 vs GPT-5.3-Codex · Claude Opus 4.8 vs GPT-5.6 Terra · Claude Opus 4.8 vs GPT-5.6 Sol · Claude Fable 5 vs Claude Opus 4.8
Full ranking: Best AI for summarising documents · model pages: Claude Opus 4.8, DeepSeek V4 Pro