Benchmark Almanac

EEBench

Claude Opus 5.5 75% leads since Sep 2026 In use

13 electrical-engineering circuit and PCB design tasks graded by deterministic build checks, simulation and BOM constraints. No LLM judge.

Made by atopile Released Sep 2026 Electronics Last in a launch post Sep 2026 Last model added Oct 2026 Scores refreshed 2 Nov 2026
Level
Expert Specialists with years of training, often over hours of work
Scored
Checked automatically A program checks the result against an answer key, unit tests or the expected final state.
Answers
Code A program or patch run against tests.
Leaderboard
26
Models scored on its own leaderboard
1
Launch post lists it, from 1 lab
3
System cards report it, from 1 lab

Claude Opus 5.5 leads with 75%

Best score per model from the benchmark's own leaderboard, read on 2 Nov 2026. Where a model ran with several settings or harnesses, we keep its best. Every run is in the next chart.

26 models. Scroll sideways for the rest.

  1. 75.0 Claude Opus 5.5
  2. 69.3 GPT-6 Astra
  3. 67.2 Claude Sonnet 5.5
  4. 67.1 Gemini 4 Argon
  5. 67.1 Claude Haiku 5.5
  6. 64.0 Grok 4.7
  7. 63.6 GPT-6.1 Sol
  8. 62.7 Muse Wonder
  9. 61.6 Claude Opus 5
  10. 57.1 Grok 4.6
  11. 56.4 Claude Fable 5.1
  12. 56.3 GPT-6 Sol
  13. 55.4 Gemini 3.8 Flash
  14. 54.3 Claude Fable 5
  15. 51.4 Claude Opus 4.8
  16. 50.9 Grok 4.5
  17. 49.4 Muse Spark 1.3
  18. 46.3 Gemini 3.1 Pro
  19. 40.3 Claude Sonnet 5
  20. 37.4 Gemini 3.6 Flash
  21. 34.3 Gemini 3.5 Flash
  22. 31.1 GPT-6 Luna
  23. 20.4 Claude Sonnet 4.6
  24. 19.5 Gemini 3 Flash
  25. 18.0 Grok Build 0.1
  26. 3.50 Claude Haiku 4.5
  1. 1 Claude Opus 5.5 xhigh 75%
  2. 2 GPT-6 Astra 69.3%
  3. 3 Claude Sonnet 5.5 xhigh 67.2%
  4. 4 Gemini 4 Argon high 67.1%
  5. 5 Claude Haiku 5.5 high 67.1%
  6. 6 Grok 4.7 64%
  7. 7 GPT-6.1 Sol high 63.6%
  8. 8 Muse Wonder high 62.7%
  9. 9 Claude Opus 5 61.6%
  10. 10 Grok 4.6 57.1%
  11. 11 Claude Fable 5.1 high 56.4%
  12. 12 GPT-6 Sol xhigh 56.3%
  13. 13 Gemini 3.8 Flash high 55.4%
  14. 14 Claude Fable 5 54.3%
  15. 15 Claude Opus 4.8 max 51.4%
  16. 16 Grok 4.5 50.9%
  17. 17 Muse Spark 1.3 high 49.4%
  18. 18 Gemini 3.1 Pro 46.3%
  19. 19 Claude Sonnet 5 40.3%
  20. 20 Gemini 3.6 Flash 37.4%
  21. 21 Gemini 3.5 Flash 34.3%
  22. 22 GPT-6 Luna high 31.1%
  23. 23 Claude Sonnet 4.6 20.4%
  24. 24 Gemini 3 Flash 19.5%
  25. 25 Grok Build 0.1 18%
  26. 26 Claude Haiku 4.5 3.50%
#ModelScoreSettingDateSource
1 Claude Opus 5.5 75% xhigh, Claude Code Sep 2026 Official leaderboard
2 GPT-6 Astra 69.3% Codex CLI Sep 2026 Official leaderboard
3 Claude Sonnet 5.5 67.2% xhigh, Claude Code Sep 2026 Official leaderboard
4 Gemini 4 Argon 67.1% high, Gemini CLI Sep 2026 Official leaderboard
5 Claude Haiku 5.5 67.1% high, Claude Code Oct 2026 Official leaderboard
6 Grok 4.7 64% Grok CLI Sep 2026 Official leaderboard
7 GPT-6.1 Sol 63.6% high, Codex CLI Sep 2026 Official leaderboard
8 Muse Wonder 62.7% high, Muse Code Oct 2026 Official leaderboard
9 Claude Opus 5 61.6% Claude Code Jul 2026 Official leaderboard
10 Grok 4.6 57.1% Grok CLI Aug 2026 Official leaderboard
11 Claude Fable 5.1 56.4% high, Claude Code Sep 2026 Official leaderboard
12 GPT-6 Sol 56.3% xhigh, Codex CLI Sep 2026 Official leaderboard
13 Gemini 3.8 Flash 55.4% high, Gemini CLI Sep 2026 Official leaderboard
14 Claude Fable 5 54.3% Claude Code Jun 2026 Official leaderboard
15 Claude Opus 4.8 51.4% max, Claude Code May 2026 Official leaderboard
16 Grok 4.5 50.9% Grok CLI Jul 2026 Official leaderboard
17 Muse Spark 1.3 49.4% high, Muse Code Sep 2026 Official leaderboard
18 Gemini 3.1 Pro 46.3% Gemini CLI Feb 2026 Official leaderboard
19 Claude Sonnet 5 40.3% Claude Code Jun 2026 Official leaderboard
20 Gemini 3.6 Flash 37.4% Gemini CLI Jul 2026 Official leaderboard
21 Gemini 3.5 Flash 34.3% Gemini CLI May 2026 Official leaderboard
22 GPT-6 Luna 31.1% high, Codex CLI Sep 2026 Official leaderboard
23 Claude Sonnet 4.6 20.4% Claude Code Feb 2026 Official leaderboard
24 Gemini 3 Flash 19.5% Gemini CLI Dec 2025 Official leaderboard
25 Grok Build 0.1 18% Grok CLI May 2026 Official leaderboard
26 Claude Haiku 4.5 3.50% Claude Code Oct 2025 Official leaderboard

Labs report scores for 2 models in their cards. We plot every source in the charts below.

The best score, 75%, costs $2.37 a task

Runs on the cost frontier score higher than any run that's cheaper. The costs are the leaderboard's own estimates, so compare them only within this benchmark.

OpenAI Anthropic Cost frontier One model at each effort level
0% 20% 40% 60% 80% 100% $0.01 $0.10 $1.00 $10 Cost per task, log scale Claude Opus 5.5, xhigh GPT-6 Astra GPT-6.1 Sol, high GPT-6 Luna, high 0% 20% 40% 60% 80% 100% $0.01 $0.10 $1.00 $10 Cost per task, log scale Claude Opus 5.5, xhigh GPT-6 Astra
ModelEffortHarnessScoreCost per taskOutput tokens
Claude Opus 5.5 xhigh Claude Code 75% $2.37 65,077
GPT-6 Astra Codex CLI 69.3% $0.83 5,967
Claude Opus 5.5 high Claude Code 68.9% $0.65 20,320
Claude Sonnet 5.5 xhigh Claude Code 67.2% $0.83 44,780
Gemini 4 Argon high Gemini CLI 67.1% $1.90 73,041
Claude Haiku 5.5 high Claude Code 67.1% $0.71 150,156
Grok 4.7 Grok CLI 64% $3.55 81,243
GPT-6.1 Sol high Codex CLI 63.6% $0.30 17,181
Muse Wonder high Muse Code 62.7% $1.14 27,725
Claude Opus 5 Claude Code 61.6% $2.38 49,030
Grok 4.6 Grok CLI 57.1% $2.11 126,635
Claude Fable 5.1 high Claude Code 56.4% $2.92 40,465
GPT-6 Sol xhigh Codex CLI 56.3% $0.65 26,759
Gemini 3.8 Flash high Gemini CLI 55.4% $1.38 68,165
Claude Fable 5 Claude Code 54.3% $3.19 33,224
Claude Opus 4.8 max Claude Code 51.4% $5.73 126,821
Grok 4.5 Grok CLI 50.9% $1.14 27,806
Muse Spark 1.3 high Muse Code 49.4% $0.84 48,389
Gemini 3.1 Pro Gemini CLI 46.3% $0.84 28,279
Claude Sonnet 5 Claude Code 40.3% $4.21 85,208
Gemini 3.6 Flash Gemini CLI 37.4% $1.92 47,303
Claude Opus 4.8 high Claude Code 35.2% $1.44 34,450
Gemini 3.5 Flash Gemini CLI 34.3% $1.11 41,102
GPT-6 Luna high Codex CLI 31.1% $0.04 33,945
Claude Sonnet 4.6 Claude Code 20.4% $1.89 80,080
Gemini 3 Flash Gemini CLI 19.5% $0.40 53,382
Grok Build 0.1 Grok CLI 18% $1.66 56,810
Claude Haiku 4.5 Claude Code 3.50% $0.41 31,601

3 models have held number one since its release in Sep 2026

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 and what labs claim in their cards.

Anthropic OpenAI xAI
Own leaderboard 3 leaders
Claude Opus 5.5 75%
Lab claims 2 leaders
Grok 4.7 66%

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 Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) Claude Opus 5.5 GPT-6 Astra Claude Opus 5 Claude Fable 5 Gemini 3.1 Pro Claude Sonnet 4.6 Claude Haiku 4.5 0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) Claude Opus 5.5 Claude Opus 5

One lab put it in a launch post in the last six months

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.

xAI
DateLaunch postScoreAs the post writes it
21 Sep 2026 Grok 4.7 64 EEBench (Electrical engineering)

3 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 Sep 2026 Grok 4.7 model card 66 EEBench V1 core corpus, reward, xhigh, Grok Build harness, run by Atopile (4.1) Capabilities
12 Aug 2026 Grok 4.6 model card 60 EEBench V1 core corpus, reward, xhigh, Grok Build harness, run by Atopile (4.1). High = 53.0% Capabilities
14 Jul 2026 Grok 4.5 model card EEBench V1 core corpus, score vs output tokens scatter, no printed value for Grok 4.5 (3.1) Capabilities

More in Engineering and CAD

All 18 in Engineering and CAD
  • BenchCAD In use Programmatic CAD: 17,900 execution-verified CadQuery programs over 106 industrial part families. Four matched tasks scored on geometry. GPT-6 Astra 95.9%
  • Parametric CAD Bench In use Agents author editable parametric FreeCAD part designs, graded against held-back references for geometry and spec consistency. Claude Opus 5.5 61%
  • CADGenBench Only in system cards Agents construct CAD models from design prompts. The generation split is graded for executability and geometric correctness. Claude Fable 5 45.1%
  • 3DCodeBench Only in system cards Agentic procedural 3D modeling via code: author engine-ready 3D assets through software APIs. Graded for executability and shape fidelity. Grok 4.6 54%
  • PartBench Only in system cards Parametric mechanical part design and CAD-style generation, graded for geometric and manufacturing fidelity. Grok 4.6 58.5%
  • Physical-Engineering's Last Exam Not in model cards Agents produce billable engineering deliverables such as calculation packages, drawings and design reviews in 85 tasks across electrical, civil, structural and mechanical engineering. Automatic graders check constraints, safety limits and the design objective. Claude Opus 5.5 0.49