Benchmark Almanac

DeepResearch Bench

Claude Opus 4.6 55.3% leads since Feb 2026 Fading

Agents write cited research reports for 100 PhD-level tasks across 22 fields. Judges score report quality against references and check citation accuracy.

The official judge model changed from Gemini 2.5 Pro to GPT-5.5 in May 2026, so older and newer scores do not compare directly.

In the authors’ words

Deep Research Agents are a prominent category of LLM-based agents. By autonomously orchestrating multistep web exploration, targeted retrieval, and higher-order synthesis, they transform vast amounts of online information into analyst-grade, citation-rich reports–compressing hours of manual desk research into minutes. However, a comprehensive benchmark for systematically evaluating the capabilities of these agents remains absent. To bridge this gap, we present DeepResearch Bench, a benchmark consisting of 100 PhD-level research tasks, each meticulously crafted by domain experts across 22 distinct fields. Evaluating DRAs is inherently complex and labor-intensive. We therefore propose two novel methodologies that achieve strong alignment with human judgment. The first is a reference-based method with adaptive criteria to assess the quality of generated research reports. The other framework is introduced to evaluate DRA's information retrieval and collection capabilities by assessing its effective citation count and overall citation accuracy. We have open-sourced DeepResearch Bench and key components of these frameworks at https://github.com/Ayanami0730/deep_research_bench to accelerate the development of practical LLM-based agents.

Abstract of DeepResearch Bench: A Comprehensive Benchmark for Deep Research Agents (arXiv:2506.11763, CC0)
Made by University of Science and Technology of China and Metastone Technology Released Jun 2025 Deep research All tasks public Last in a launch post Feb 2026 , dropped before it saturated Last model added May 2026 Scores refreshed 2 Nov 2026
Level
Expert Specialists with years of training, often over hours of work
Scored
Graded by a model A language model scores each response, usually against a rubric.
Answers
Open-ended Free-form text, documents, designs or media judged as a whole.
24
Models scored in Epoch AI data
3
Launch posts list it, from 2 labs
2
System cards report it, from 1 lab

Claude Opus 4.6 leads with 55.3% among models released by May 2026

Best score per model in Epoch AI’s data. Where a model ran with several settings or harnesses, we keep its best.

The newest model with a score here came out in May 2026, and nobody has tested a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:

  1. 1 Claude Opus 4.6 high 55.3%
  2. 2 Claude Sonnet 4.6 high 54.9%
  3. 3 Claude Opus 4.5 high 54.8%
  4. 4 GPT-5.5 high 54%
  5. 5 Claude Sonnet 4.5 2k thinking 52.6%
  6. 6 Claude Opus 4.8 high 50.2%
  7. 7 Gemini 3 Flash low 49.8%
  8. 8 GPT-5 low 49.6%
  9. 9 Claude Opus 4.1 48.3%
  10. 10 Gemini 3.1 Pro high 47.8%
  11. 11 Grok 4 47.3%
  12. 12 Claude Opus 4 2K 46.8%
  13. 13 Claude Sonnet 4 2K 46.6%
  14. 14 Gemini 3 Pro low 46.3%
  15. 15 Claude Haiku 4.5 low 45.5%
  16. 16 o3 medium 45.2%
  17. 17 Claude 3.7 Sonnet 2k thinking 43.6%
  18. 18 Gemini 2.5 Pro Jun 2025 42.8%
  19. 19 GPT-5.1 low 42.8%
  20. 20 GPT-5.2 low 41.1%
  21. 21 Gemini 3.1 Flash-Lite low 37.3%
  22. 22 GPT-5.4 Mini low 36.3%
  23. 23 DeepSeek-R1 May 2025 35.1%
  24. 24 GPT-5.4 low 35.1%
#ModelScoreSettingDateSource
1 Claude Opus 4.6 55.3% high Feb 2026 Epoch AI
2 Claude Sonnet 4.6 54.9% high Feb 2026 Epoch AI
3 Claude Opus 4.5 54.8% high Nov 2025 Epoch AI
4 GPT-5.5 54% high Apr 2026 Epoch AI
5 Claude Sonnet 4.5 52.6% 2k thinking Sep 2025 Epoch AI
6 Claude Opus 4.8 50.2% high May 2026 Epoch AI
7 Gemini 3 Flash 49.8% low Dec 2025 Epoch AI
8 GPT-5 49.6% low Aug 2025 Epoch AI
9 Claude Opus 4.1 48.3% Aug 2025 Epoch AI
10 Gemini 3.1 Pro 47.8% high Feb 2026 Epoch AI
11 Grok 4 47.3% True Jul 2025 Epoch AI
12 Claude Opus 4 46.8% 2K May 2025 Epoch AI
13 Claude Sonnet 4 46.6% 2K May 2025 Epoch AI
14 Gemini 3 Pro 46.3% low Nov 2025 Epoch AI
15 Claude Haiku 4.5 45.5% low Oct 2025 Epoch AI
16 o3 45.2% medium Apr 2025 Epoch AI
17 Claude 3.7 Sonnet 43.6% 2k thinking Feb 2025 Epoch AI
18 Gemini 2.5 Pro Jun 2025 42.8% Jun 2025 Epoch AI
19 GPT-5.1 42.8% low Nov 2025 Epoch AI
20 GPT-5.2 41.1% low Dec 2025 Epoch AI
21 Gemini 3.1 Flash-Lite 37.3% low Mar 2026 Epoch AI
22 GPT-5.4 Mini 36.3% low Mar 2026 Epoch AI
23 DeepSeek-R1 May 2025 35.1% May 2025 Epoch AI
24 GPT-5.4 35.1% low Mar 2026 Epoch AI

The benchmark's own leaderboard has 43 entries, 4 of them models we track. Labs report scores for 2 models in their cards. We plot every source in the charts below.

2 models have held number one since its release in Jun 2025

Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard, Epoch AI’s runs and what labs claim in their cards.

OpenAI Anthropic xAI ByteDance Seed
Own leaderboard Not tested since Aug 2025
GPT-5 50.6%
Epoch AI runs Not tested since May 2026
Lab claims Not tested since Mar 2026
Seed2.0 Pro 53.3%

Scores over time

All the scores we have, one dot each, so a model tested at several settings appears more than once.

On the benchmark’s own leaderboard Run or collected by Epoch AI Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2025 2026 Near the ceiling (85%) Claude Opus 4.6 Claude Sonnet 4.5 Claude Opus 4.1 OpenAI deep research Sonar Pro 0% 20% 40% 60% 80% 100% 2025 2026 Near the ceiling (85%) Claude Opus 4.6 Claude Opus 4.1

Labs headline it less often now, last in Feb 2026

Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.

Cohere
ByteDance Seed
DateLaunch postScoreAs the post writes it
14 Feb 2026 Seed2.0 Pro 53.3 DeepResearchBench
18 Dec 2025 Seed1.8 43.5 DeepResearchBench
21 Aug 2025 Command A Reasoning DeepResearch Bench RACE overall, English questions, Cohere's deep research agent powered by the model (chart only, about 48.6)

2 system cards report it, from 1 lab

Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.

DateDocumentScoreAs the document writes itSection
21 Mar 2026 Seed1.8 model card 43.5 DeepResearchBench (Table 4) Capabilities
14 Feb 2026 Seed2.0 Pro model card 53.3 DeepResearchBench (Table 11) Capabilities

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