FrontierCS 1.1
Agents solve 179 algorithmic tasks under revised scoring that rewards solutions beyond the reference. The score is the official average task score.
Version 1.1 changes the task set and scoring. It is separate from 1.0 and the research-focused FrontierCS 2.
- Released
- December 2025
- Kind
- Competitive programming
- Level
- Research frontier
- Scored
- Checked automatically
- Answers
- Code
- Tasks
- All public
- Strongest model tested
- GPT-6 Astra #3 on the capability index
- Last model added
- September 2026
- Scores refreshed
- November 12th, 2026
In the authors’ words
We introduce FrontierCS, a benchmark of 156 open-ended problems across diverse areas of computer science, designed and reviewed by experts, including CS PhDs and top-tier competitive programming participants and problem setters. Unlike existing benchmarks that focus on tasks with known optimal solutions, FrontierCS targets problems where the optimal solution is unknown, but the quality of a solution can be objectively evaluated. Models solve these tasks by implementing executable programs rather than outputting a direct answer. FrontierCS includes algorithmic problems, which are often NP-hard variants of competitive programming problems with objective partial scoring, and research problems with the same property. For each problem we provide an expert reference solution and an automatic evaluator. Combining open-ended design, measurable progress, and expert curation, FrontierCS provides a benchmark at the frontier of computer-science difficulty. Empirically, we find that frontier reasoning models still lag far behind human experts on both the algorithmic and research tracks, that increasing reasoning budgets alone does not close this gap, and that models often over-optimize for generating merely workable code instead of discovering high-quality algorithms and system designs.
Claude Opus 5.5 leads with 56.5 among models released by September 2026
Best score per model from the benchmark's own leaderboard, read on November 12th, 2026. Where a model ran with several settings or harnesses, we keep its best.
The newest model with a score here came out in September 2026, and nobody has tested a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:
- Claude Fable 5.2
-
Gemini 4 Carbon
- GPT-6.1 Sol
- GPT-6.1 Terra
- and 12 more
- 1 Claude Opus 5.5 High 56.5
- 2 GPT-6 Astra Low 54.0
- 3 Claude Sonnet 5.5 Max 53.9
- 4 GPT-6 Sol High 52.4
- 5
Gemini 3.7 Flash Medium 48.0
- 6
Gemini 3.8 Flash Medium 47.8
Source: Official FrontierCS 1.1 leaderboard
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | Claude Opus 5.5 | 56.5 | High, Claude Code | Sep 2026 | Official leaderboard |
| 2 | GPT-6 Astra | 54.0 | Low, Codex CLI | Sep 2026 | Official leaderboard |
| 3 | Claude Sonnet 5.5 | 53.9 | Max, Claude Code | Sep 2026 | Official leaderboard |
| 4 | GPT-6 Sol | 52.4 | High, Codex CLI | Sep 2026 | Official leaderboard |
| 5 | | 48.0 | Medium, Gemini CLI | Aug 2026 | Official leaderboard |
| 6 | | 47.8 | Medium, Gemini CLI | Sep 2026 | Official leaderboard |
3 models have held number one on the official leaderboard since its release in December 2025
Lab claims count from the day the card came out, independent runs from the model’s release.
Source: Official FrontierCS 1.1 leaderboard
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Source: Official FrontierCS 1.1 leaderboard
No lab model card reports it yet
We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark.
Versions
More in Coding
- SWE-bench Verified In use 500 human-validated GitHub issues from 12 Python repos. Agent writes a patch that must pass hidden tests. Claude Opus 4.7 83.5%
- LiveCodeBench v6 In use Competitive programming problems collected after model cutoffs from LeetCode, AtCoder, Codeforces. Scored pass@1 on hidden tests.
DeepSeek-V4-Pro 93.5%
- SWE-bench Multilingual In use 300 GitHub-issue tasks across nine programming languages in SWE-bench format. Patch graded by repository tests. Claude Fable 5.2 96.6%
- DeepSWE In use 113 original long-horizon engineering tasks across 91 repos and five languages, written from scratch. Hand-written verifiers accept alternative solutions. GPT-6 Astra 74.1%
- SciCode In use Scientist-curated research coding problems split into subproblems across natural sciences. Code checked against test cases.
Seed2.1 Pro 59.8%
- Codeforces rating In use Model solves recent Codeforces contest problems. An Elo-style rating is computed from simulated contest performance.
DeepSeek V4.1 Flash 3,471