head-to-head
| Metric | Claude Opus 5 | GPT-5.6 Luna |
|---|---|---|
| SWE-bench Verified | 97.0% | 93.0% |
| SWE-bench Pro | — | — |
| Terminal-Bench | — | — |
| Input $ / 1M | $5 | — |
| Output $ / 1M | $25 | — |
| Context | — | — |
| Open weights | No | No |
| Access | API (claude-opus-5) · Claude Code · Claude Cowork · claude.ai (Pro, Max) | API |
| Maker | Anthropic | OpenAI |
what do the benchmarks actually say?
On SWE-bench Verified — real, human-validated GitHub issues resolved end-to-end — Claude Opus 5 posts 97.0% against 93.0% for GPT-5.6 Luna, a 4-point gap. Verified is the closest public proxy for "can it fix a real bug in a real repo without help", which is why it anchors our ranking.
A few points either way is real but not decisive: within that band, the agent scaffolding around the model — how it retrieves files, runs tests, and retries — often matters as much as the base model. Treat the gap as a lean, not a verdict.
which is cheaper to run?
Public per-token pricing isn't confirmed for both models, so we don't print a cost comparison yet.
when to pick each
The highest independently measured coding score on the board at 97.0%, at half the price of Fable 5. Strongest on short and medium tasks, though GPT-5.6 Sol still edges it on multi-hour work.
The cost outlier of the leaders: within striking distance of the top scores while costing a fraction per solved task, which makes it the obvious candidate for high-volume agent runs.
how were these scores verified?
We only print a number once it's confirmed against a primary source or an independent evaluation, and each row on our leaderboard records which kind it is:
- Claude Opus 5: Independent (vals.ai, observed Jul 25 2026, mini-swe-agent bash-only harness): SWE-bench Verified 97.00% ±0.76, the highest score on the board and 1st of the 75 systems vals.ai has run. Entered ranked Jul 25, 2026 after one day unranked: Anthropic published no SWE-bench Verified number at launch and still has not, so this is vals.ai's own measurement rather than a vendor claim. Read the #1 as a three-way tie, not a win — GPT-5.6 Sol is at 96.20% ±0.86 (a 0.8-point gap, ~0.7 sigma) and Claude Fable 5 at 95.00% ±0.98 (2.0 points, ~1.6 sigma), both inside the combined margin of error. We rank Opus 5 first only because it scored highest. Where the top two genuinely separate is task length, and not in Opus 5's favour: on the 1-to-4-hour tier Sol solves 98% against Opus 5's 90%, while Opus 5 leads on shorter work (98% under 15 minutes and 97% on 15-minute-to-1-hour tasks, vs 97% and 95% for Sol). Released Jul 24, 2026 at $5/$25 per 1M, the same price as Opus 4.8 and half of Fable 5. Anthropic's launch claims stay unreproducible (Frontier-Bench v0.1, CursorBench 3.2 and Zapier AutomationBench are proprietary), so this is the first externally checkable score the model has. Fast mode runs about 2.5x default speed at 2x base price.
- GPT-5.6 Luna: Independent (vals.ai, eval listed Jul 17 2026, mini-swe-agent bash-only harness): SWE-bench Verified 93.00% ±1.14. Added Jul 21, 2026 — this row was missing from the board even though vals.ai had already evaluated Luna, and our Kimi K3 note referenced its 93.0% score without ever listing it; adding it moves every row below it down one rank. Treat 3rd and 4th as a tie: Kimi K3's 93.40% ±1.11 is 0.4 points higher, well inside the combined margin of error (~0.25 sigma), so the ordering between them is not significant. Like the rest of the GPT-5.6 family, OpenAI has published no SWE-bench Verified figure of its own, so we rank on the independent number per our standing rule. The striking number is cost: vals.ai measured $0.21 per test against $1.15 for GPT-5.6 Sol, $1.92 for Claude Opus 4.8 and $2.05 for Claude Fable 5, at 201s median latency. Per-token list pricing not confirmed against OpenAI's own pricing page, so inPrice/outPrice stay blank rather than estimated.
Full reviewsClaude Opus 5, decoded
Ranked on our AI Coding Leaderboard, updated 2026-07-25. Scores are confirmed against primary sources; prices are per 1M input tokens and can change.
- Anthropicvals.ai — SWE-bench Verified (independent) — Independent (vals.ai, observed Jul 25 2026, mini-swe-agent bash-only harness): SWE-bench Verified 97.00% ±0.76, the highest score on the board and 1st of the 75 systems vals.ai has run. Entered ranked Jul 25, 2026 after one day unranked: Anthropic published no SWE-bench Verified number at launch and still has not, so this is vals.ai's own measurement rather than a vendor claim. Read the #1 as a three-way tie, not a win — GPT-5.6 Sol is at 96.20% ±0.86 (a 0.8-point gap, ~0.7 sigma) and Claude Fable 5 at 95.00% ±0.98 (2.0 points, ~1.6 sigma), both inside the combined margin of error. We rank Opus 5 first only because it scored highest. Where the top two genuinely separate is task length, and not in Opus 5's favour: on the 1-to-4-hour tier Sol solves 98% against Opus 5's 90%, while Opus 5 leads on shorter work (98% under 15 minutes and 97% on 15-minute-to-1-hour tasks, vs 97% and 95% for Sol). Released Jul 24, 2026 at $5/$25 per 1M, the same price as Opus 4.8 and half of Fable 5. Anthropic's launch claims stay unreproducible (Frontier-Bench v0.1, CursorBench 3.2 and Zapier AutomationBench are proprietary), so this is the first externally checkable score the model has. Fast mode runs about 2.5x default speed at 2x base price.
- OpenAIvals.ai — SWE-bench Verified (independent) — Independent (vals.ai, eval listed Jul 17 2026, mini-swe-agent bash-only harness): SWE-bench Verified 93.00% ±1.14. Added Jul 21, 2026 — this row was missing from the board even though vals.ai had already evaluated Luna, and our Kimi K3 note referenced its 93.0% score without ever listing it; adding it moves every row below it down one rank. Treat 3rd and 4th as a tie: Kimi K3's 93.40% ±1.11 is 0.4 points higher, well inside the combined margin of error (~0.25 sigma), so the ordering between them is not significant. Like the rest of the GPT-5.6 family, OpenAI has published no SWE-bench Verified figure of its own, so we rank on the independent number per our standing rule. The striking number is cost: vals.ai measured $0.21 per test against $1.15 for GPT-5.6 Sol, $1.92 for Claude Opus 4.8 and $2.05 for Claude Fable 5, at 201s median latency. Per-token list pricing not confirmed against OpenAI's own pricing page, so inPrice/outPrice stay blank rather than estimated.
- BenchmarkSWE-bench — the real-GitHub-issue benchmark