Benchmark
CoBench
Benchmark by Anthropic
2.1
53.2%
Claude Opus 5
frontier lab
Anthropic
CoBench and operational automation included. Internal tasks are not public; lab disclosure is not independent replication.
Published evidence
Benchmark
CoBench
Benchmark by Anthropic
2.1
53.4%
Claude Mythos 5.1
Benchmark
CoBench
Benchmark by Anthropic
2.1
55.8%
Claude Opus 5.5
Benchmark
CoBench
Benchmark by Anthropic
Prior version (label unspecified)
59.6%
Claude Opus 5
Benchmark
CoBench
Benchmark by Anthropic
Prior version (label unspecified)
57.6%
Claude Mythos 5.1
Benchmark
PaperBench
Benchmark by OpenAI
Original paper v1
21.0 ± 0.8%
Claude 3.5 Sonnet (New) / BasicAgent
Benchmark
PaperBench
Benchmark by OpenAI
Original paper v1
16.1 ± 0.1%
Claude 3.5 Sonnet (New) / IterativeAgent
Benchmark
MLE-bench
Benchmark by OpenAI
Original paper v1 (2024)
7.6 ± 1.8%
Claude 3.5 Sonnet / AIDE
Benchmark
Task-completion time horizons
Benchmark by METR
TH1 (historical estimates)
289 minutes
Claude Opus 4.5 / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1.1
320 minutes
Claude Opus 4.5 / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1 (historical estimates)
86 minutes
Claude Opus 4 / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1.1
101 minutes
Claude Opus 4 / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1 (historical estimates)
56 minutes
Claude 3.7 Sonnet / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1.1
60 minutes
Claude 3.7 Sonnet / METR horizon evaluation
Benchmark
AI4AI-Bench
Benchmark by AI4AI-Bench authors
Paper v1
0.250 normalized score
Claude Opus 5 / Claude Code effort aggregate
Benchmark
AI4AI-Bench
Benchmark by AI4AI-Bench authors
Paper v1
0.145 normalized score
Claude Sonnet 5 / Claude Code effort aggregate
Indicator
Anthropic R&D Automation Index
Measure by Anthropic
August 2026 snapshot
26%
Anthropic
Indicator
Anthropic R&D Automation Index
Measure by Anthropic
August 2026 snapshot
No measured subset fully autonomous
Anthropic
Benchmark
Task-completion time horizons
Benchmark by METR
TH1 (historical estimates)
122 minutes
Claude Sonnet 4.5 / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1 (historical estimates)
114 minutes
Claude Opus 4.1 / METR horizon evaluation
Benchmark
Task-completion time horizons
Benchmark by METR
TH1 (historical estimates)
75 minutes
Claude Sonnet 4 / METR horizon evaluation
Benchmark
AI4AI-Bench
Benchmark by AI4AI-Bench authors
Paper v1
0.288 normalized score
Claude Opus 5 / Claude Code, medium effort
Relevant sources
Claude Opus 5.5 System Card ↗
system card · 2026-09-22 · available
Measurements for understanding the pace of AI development inside frontier labs ↗
organizational research article · 2026-09-17 · available