Anthropic ECI - October 2026 Fit (METR Assessment): leaderboard
METR's November 5, 2026 assessment of Anthropic model capability through October 2026. AECI is an unbounded IRT index combining public and internal benchmarks; higher is better. This separate fit includes all 21 points in METR's main chart, including private models, distinct early snapshots and non-frontier models. Model 4's 178.6 is printed in the report; the other scores are approximate, digitized from the original figure to 0.1 AECI. Extraction precision is separate from the plotted statistical confidence intervals. The chart dates describe availability to most Anthropic employees, not public releases. Model 2, Model 3 and Model 4 are report-specific anonymous identities; no released-model mapping or effort setting is assumed. Scores are not interchangeable with earlier Anthropic system-card fits or public Epoch ECI. The exact benchmark basket and scored questions are not disclosed.
Metric: AECI Score. Source: metr.org. Saturation forecast: Around November 2027. 21 models tracked.
Top models
| # | Model | Score | Overall rank |
|---|---|---|---|
| 1 | Claude Opus 5.5 | 174.6 | #3 |
| 2 | Claude Mythos 5.1 | 172.5 | #2 |
| 3 | Claude Opus 5 | 169.3 | #16 |
| 4 | Claude Mythos 5 | 168.6 | #8 |
| 5 | Claude Mythos Preview | 165.6 | #7 |
| 6 | Claude Opus 4.8 | 163.4 | #40 |
| 7 | Claude Opus 4.7 | 160.3 | #52 |
| 8 | Claude Opus 4.6 | 157.3 | #68 |
| 9 | Claude Opus 4.5 | 152.3 | #88 |
| 10 | Claude Sonnet 4.5 | 147.8 | #148 |
| 11 | Claude Opus 4 | 144.8 | #171 |
| 12 | Claude 3.7 Sonnet | 141.7 | #260 |
| 13 | Claude 3.5 Sonnet (20241022) | 133.2 | #303 |
| 14 | Claude 3.5 Sonnet (20240620) | 130 | #308 |
| 15 | Claude 3 Opus | 124.7 | #564 |
No result here: #5 GPT-6 Astra, #6 GPT-6.1 Sol, #9 Gemini 4 Argon.
Interactive version: theaggregate.ai/benchmark?slug=anthropic-eci-october-2026-fit-metr-assessment · How It Works · Data refreshed daily, snapshot 2026-11-06.