Claude Opus 4.7 is verified: Anthropic officially announced it on Apr. 16, 2026 and said it is generally available.^[1] In the retrieved evidence, “GPT-5.5 Spud” appeared on third-party pages about upcoming OpenAI models rather than in a primary OpenAI release document, so the evidence does not support a clean Claude-vs-Spud head-to-head yet.^[2][3] On benchmark credibility, the strongest signals come from contamination-limited or contamination-resistant public benchmarks such as LiveBench and newer SWE-bench variants, not from release-day charts alone.^{[4][5][6][7][8]}

Key findings

• Model status: Claude Opus 4.7 is a real, released Anthropic model.^[1] In the retrieved evidence, mentions of “GPT-5.5 Spud” were on third-party pages describing “next” or unreleased OpenAI models.^[2][3]

• Benchmark credibility: LiveBench was explicitly designed to resist contamination by using recent-source questions, objective ground-truth scoring, and monthly updates.^[4] A later benchmark survey says dynamic benchmark designs like LiveBench reduce data-leakage risk.^[5]

• SWE-bench is useful, but raw leaderboard scores need caution: SWE-bench Live restricts tasks to issues created between Jan. 1, 2024 and Apr. 20, 2025 to reduce pretraining contamination, and its authors note that leaderboard setups can differ substantially.^[6] SWE-bench Pro is presented as a more contamination-resistant benchmark for longer-horizon software-engineering tasks.^[7]

• Contamination risk remains material: SWE-Bench++ argues that public GitHub-based software benchmarks face critical contamination risk and that solution leakage can skew rankings.^[9] A 2026 analysis of SWE-Bench leaderboards also reports recent Verified submissions with data contamination.^[10]

• Saturation and benchmark gaming are also real risks: one 2026 benchmarking paper says results that look strong on SWE-bench Verified can drop to 23% on SWE-bench Pro.^[11] SWE-ABS separately argues that Verified is approaching saturation and can show inflated success rates until tasks are adversarially strengthened.^[12]

• Independent replication is still thin: a broader 2025 assessment of major LLM evaluations says many claims now have clearer methods but still limited independent replication.^[8] Inference: that caution applies to fresh Opus 4.7 launch claims until stronger third-party replications appear.^[1][8]

• Practical takeaway: if you want the most trustworthy performance signal today, put the most weight on contamination-limited/resistant, publicly inspectable benchmarks and repeated third-party tests, and less weight on vendor launch charts.^{[4][5][7][8][9][10][11][12]}

Evidence notes

• I did not retrieve a primary OpenAI announcement, model card, or system card for “GPT-5.5 Spud.”

• I also did not retrieve a strong, independent, apples-to-apples replication of Claude Opus 4.7 versus a verified GPT-5.5 Spud model.

• Sources

  • ^[1] Anthropic, “Introducing Claude Opus 4.7” — https://www.anthropic.com/news/claude-opus-4-7
  • ^[2] Pasquale Pillitteri, “GPT-5.5 Spud and GPT Image 2: Complete Guide to OpenAI Next Models in 2026” — https://pasqualepillitteri.it/en/news/741/gpt-5-5-spud-gpt-image-2-openai-complete-guide-2026
  • ^[3] Idlen, “OpenAI Spud: GPT-6 Release Between April 14 and May 5, 2026” — https://www.idlen.io/news/openai-spud-gpt6-release-april-14-may-5-super-app-ambient-computing
  • ^[4] White et al., “LiveBench: A Challenging, Contamination-Limited LLM Benchmark” — https://arxiv.org/abs/2406.19314
  • ^[5] “A survey on large language model benchmarks” — https://arxiv.org/abs/2508.15361
  • ^[6] “Swe-bench goes live!” — https://arxiv.org/abs/2505.23419
  • ^[7] “Swe-bench pro: Can AI agents solve long-horizon software engineering tasks?” — https://arxiv.org/abs/2509.16941
  • ^[8] “From Benchmarks to Real-World Performance: A Data-Driven Assessment of Large Language Models in 2025” — https://papers.ssrn.com/sol3/papers.cfm?abstract_id=5991894
  • ^[9] “SWE-Bench++: A Framework for the Scalable Generation of Software Engineering Benchmarks from Open-Source Repositories” — https://arxiv.org/abs/2512.17419
  • ^[10] “What’s in a Benchmark? The Case of SWE-Bench in Automated Program Repair” — https://arxiv.org/abs/2602.04449
  • ^[11] “Towards Comprehensive Benchmarking Infrastructure for LLMs In Software Engineering” — https://arxiv.org/abs/2601.21070
  • ^[12] “SWE-ABS: Adversarial Benchmark Strengthening Exposes Inflated Success Rates on Test-based Benchmark” — https://arxiv.org/abs/2603.00520

Limitations / uncertainty

• Because “GPT-5.5 Spud” was not verified from primary-source material in the retrieved evidence, any direct Opus-4.7-vs-Spud ranking claim should be treated as provisional.^[2][3]

• Several benchmark-methodology sources here are recent arXiv or SSRN papers rather than final peer-reviewed journal versions.^{[4][5][6][7][8][9][10][11][12]}

Summary

The fact-checked conclusion is asymmetric: Claude Opus 4.7 is real and released, while “GPT-5.5 Spud” is not verified from primary-source material in the evidence I retrieved.^[1][2][3] For benchmark credibility, the best current evidence favors contamination-limited or contamination-resistant public evals such as LiveBench and SWE-bench Pro over static or vendor-only charts.^{[4][5][6][7][8][9][10][11][12]} If you want, I can turn this into a stricter buyer’s guide with a simple trust ranking for specific benchmarks like LiveBench, SWE-bench Verified, SWE-bench Pro, HumanEval, and vendor internal evals.