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BenchLM

VulcanBench Coding Intelligence Index v1 (VulcanBench CII v1)

A post-cutoff software-engineering benchmark with hidden functional tests and regression guards, reported for vendor coding-agent harnesses.

Data verified 22 confirmed releases in the last 30 daysStart free brief

Benchmark score on VulcanBench CII v1 — August 24, 2026

We mirror the published score view for VulcanBench CII v1. Claude Opus 5 leads the public snapshot at 96.4%, followed by GPT-5.6 Sol (86.5%). We do not use these results to rank models overall.

1Closed

Claude Opus 5

Anthropic

96.4%
Overall 82.69
2Closed

GPT-5.6 Sol

OpenAI

86.5%
Overall 81.8Context 1.05M
2 modelsCodingCurrentDisplay onlyUpdated August 24, 2026

Benchmark score table (2 models)

Score
1
Claude Opus 5Anthropic · Closed
96.4%
2
GPT-5.6 SolOpenAI · Closed
86.5%

About VulcanBench CII v1

Year

2026

Tasks

38 validated post-cutoff repository tasks

Format

Pass@1 with vendor coding-agent harnesses

Difficulty

Mid-band frontier software engineering

CII v1 contains 38 validated tasks from pull requests merged between May and August 2026. The published snapshot measures 37 tasks for Claude Opus 5 with Claude Code CLI and GPT-5.6 Sol with Codex CLI. These are model-plus-vendor-harness results, so we keep them display-only and preserve uncertainty, functional score, task count, and run count in the source snapshot.

CII v1 frontier results

BenchLM freshness & provenance

Version

VulcanBench CII v1 2026

Refresh cadence

Quarterly

Staleness state

Current

Question availability

Public benchmark set

CurrentDisplay only

BenchLM uses freshness metadata to decide whether a benchmark should still be treated as a strong differentiator, a benchmark to watch, or a display-only reference. For the full scoring policy, see the BenchLM methodology page.

FAQ

What does VulcanBench CII v1 measure?

A post-cutoff software-engineering benchmark with hidden functional tests and regression guards, reported for vendor coding-agent harnesses.

Which model scores highest on VulcanBench CII v1?

Claude Opus 5 by Anthropic currently leads with a score of 96.4% on VulcanBench CII v1.

How many models are evaluated on VulcanBench CII v1?

2 AI models have been evaluated on VulcanBench CII v1 on BenchLM.

Compare Top Models on VulcanBench CII v1

Claude Opus 5 vs GPT-5.6 Sol
Last updated: August 24, 2026 · BenchLM version VulcanBench CII v1 2026

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