APEX-Agents Original Effort: Medium 52.5% mercor.com for Claude Opus 5.5 (medium) on APEX-Agents Original (opens in a new tab) Archived copy (opens in a new tab) Pass rate Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on APEX-Agents Original APEX-Agents Original Effort: Max 73.5% mercor.com for Claude Opus 5.5 (max) on APEX-Agents Original (opens in a new tab) Archived copy (opens in a new tab) Pass rate Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on APEX-Agents Original AutomationBench 1.0.6 Effort: Max 40.0% www-cdn.anthropic.com for Claude Opus 5.5 (max) on AutomationBench 1.0.6 (opens in a new tab) Task pass rate Reported September 22, 2026 System card Anthropic Self-reported Zapier AutomationBench Team Record for Claude Opus 5.5 on AutomationBench 1.0.6 BrowseComp 130-question subset — Mercor web research agent Effort: Max Configuration: Mercor web research agent, 100 steps, 3 hours 88.5% mercor.com for Claude Opus 5.5 (max) on BrowseComp 130-question subset — Mercor web research agent (opens in a new tab) Archived copy (opens in a new tab) BrowseComp Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on BrowseComp 130-question subset — Mercor web research agent Chartography October 2026 leaderboard Effort: Max Reported as: Adaptive/Max 66.3% surgehq.ai for Claude Opus 5.5 (Adaptive/Max) on Chartography October 2026 leaderboard (opens in a new tab) Archived copy (opens in a new tab) Chartography Pass@1 Reported October 7, 2026 Benchmark leaderboard Surge AI Independent Record for Claude Opus 5.5 on Chartography October 2026 leaderboard CharXiv Descriptive and reasoning — Mercor single-shot Effort: Max Configuration: Mercor single-shot agent 96.4% mercor.com for Claude Opus 5.5 (max) on CharXiv Descriptive and reasoning — Mercor single-shot (opens in a new tab) Archived copy (opens in a new tab) CharXiv Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on CharXiv Descriptive and reasoning — Mercor single-shot CursorBench 4.0 Effort: Low 43.7% cursor.com for Claude Opus 5.5 (low) on CursorBench 4.0 (opens in a new tab) Archived copy (opens in a new tab) CursorBench Accuracy Reported October 7, 2026 Benchmark leaderboard Cursor Independent Record for Claude Opus 5.5 on CursorBench 4.0 CursorBench 4.0 Effort: Medium 52.5% cursor.com for Claude Opus 5.5 (medium) on CursorBench 4.0 (opens in a new tab) CursorBench Accuracy Reported September 22, 2026 Benchmark leaderboard Cursor Independent Record for Claude Opus 5.5 on CursorBench 4.0 CursorBench 4.0 Effort: High 56.0% cursor.com for Claude Opus 5.5 (high) on CursorBench 4.0 (opens in a new tab) Archived copy (opens in a new tab) CursorBench Accuracy Reported October 7, 2026 Benchmark leaderboard Cursor Independent Record for Claude Opus 5.5 on CursorBench 4.0 CursorBench 4.0 Effort: xHigh 56.0% cursor.com for Claude Opus 5.5 (xhigh) on CursorBench 4.0 (opens in a new tab) Archived copy (opens in a new tab) CursorBench Accuracy Reported October 7, 2026 Benchmark leaderboard Cursor Independent Record for Claude Opus 5.5 on CursorBench 4.0 CursorBench 4.0 Effort: Max 57.8% cursor.com for Claude Opus 5.5 (max) on CursorBench 4.0 (opens in a new tab) CursorBench Accuracy Reported September 22, 2026 Benchmark leaderboard Cursor Independent Record for Claude Opus 5.5 on CursorBench 4.0 CWE-bench 1 — Claude Code Effort: High Configuration: Claude Code harness 67.0% cwe-bench.com for Claude Opus 5.5 (high) on CWE-bench 1 — Claude Code (opens in a new tab) Archived copy (opens in a new tab) CWE-bench Programmatic Pass@1 Reported October 7, 2026 Benchmark leaderboard Collinear AI Independent Record for Claude Opus 5.5 on CWE-bench 1 — Claude Code DeepSWE 1.1 Effort: Max 74.2% www-cdn.anthropic.com for Claude Opus 5.5 (max) on DeepSWE 1.1 (opens in a new tab) DeepSWE Pass@1 Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on DeepSWE 1.1 DeepSWE 1.1 — Mercor mini-swe-agent, 500 steps Effort: Max Configuration: Mercor mini-swe-agent, 500 steps, 2 hours 72.3% mercor.com for Claude Opus 5.5 (max) on DeepSWE 1.1 — Mercor mini-swe-agent, 500 steps (opens in a new tab) Archived copy (opens in a new tab) DeepSWE Pass@1 Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on DeepSWE 1.1 — Mercor mini-swe-agent, 500 steps Finance Agent Benchmark 2 — October 2026 evaluation 58.6% vals.ai for Claude Opus 5.5 on Finance Agent Benchmark 2 — October 2026 evaluation (opens in a new tab) Archived copy (opens in a new tab) Finance Agent Accuracy Reported October 6, 2026 Benchmark leaderboard Vals AI Independent Record for Claude Opus 5.5 on Finance Agent Benchmark 2 — October 2026 evaluation FrontierSWE 2 — October 2026 evaluation Configuration: Proximus harness, 5 trials, 20-hour budget 62.3% frontierswe.com for Claude Opus 5.5 on FrontierSWE 2 — October 2026 evaluation (opens in a new tab) Archived copy (opens in a new tab) FrontierSWE Score Reported October 7, 2026 Benchmark leaderboard Proximal Independent Record for Claude Opus 5.5 on FrontierSWE 2 — October 2026 evaluation Global MMLU Original Effort: Max 94.3% www-cdn.anthropic.com for Claude Opus 5.5 (max) on Global MMLU Original (opens in a new tab) Average accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Global MMLU Original GPQA Diamond — Epoch AI harness Effort: Max Configuration: Epoch AI harness 90.6% epoch.ai for Claude Opus 5.5 (max) on Graduate-Level Google-Proof Q&A Diamond — Epoch AI harness (opens in a new tab) Archived copy (opens in a new tab) GPQA Diamond Accuracy Reported October 7, 2026 Evaluated September 22, 2026 at 6:27 PM UTC Benchmark leaderboard Epoch AI Independent Record for Claude Opus 5.5 on Graduate-Level Google-Proof Q&A Diamond — Epoch AI harness GPQA Diamond — Mercor single-shot Effort: Max Configuration: Mercor single-shot agent 91.3% mercor.com for Claude Opus 5.5 (max) on Graduate-Level Google-Proof Q&A Diamond — Mercor single-shot (opens in a new tab) Archived copy (opens in a new tab) GPQA Diamond Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on Graduate-Level Google-Proof Q&A Diamond — Mercor single-shot HLAB October 2026 evaluation 3.8% vals.ai for Claude Opus 5.5 on Harvey's Legal Agent Benchmark October 2026 evaluation (opens in a new tab) Archived copy (opens in a new tab) HLAB Task Pass Rate Reported October 6, 2026 Benchmark leaderboard Vals AI Independent Record for Claude Opus 5.5 on Harvey's Legal Agent Benchmark October 2026 evaluation Humanity's Last Exam Full set — No tools Effort: Low Configuration: No tools 52.9% www-cdn.anthropic.com for Claude Opus 5.5 (low) on Humanity's Last Exam Full set — No tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — No tools Humanity's Last Exam Full set — No tools Effort: Medium Configuration: No tools 59.0% www-cdn.anthropic.com for Claude Opus 5.5 (medium) on Humanity's Last Exam Full set — No tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — No tools Humanity's Last Exam Full set — No tools Effort: High Configuration: No tools 59.6% www-cdn.anthropic.com for Claude Opus 5.5 (high) on Humanity's Last Exam Full set — No tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — No tools Humanity's Last Exam Full set — No tools Effort: xHigh Configuration: No tools 62.8% www-cdn.anthropic.com for Claude Opus 5.5 (xhigh) on Humanity's Last Exam Full set — No tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — No tools Humanity's Last Exam Full set — No tools Effort: Max Configuration: No tools 64.4% www-cdn.anthropic.com for Claude Opus 5.5 (max) on Humanity's Last Exam Full set — No tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — No tools Humanity's Last Exam Full set — With tools Effort: Low Configuration: With tools 57.4% www-cdn.anthropic.com for Claude Opus 5.5 (low) on Humanity's Last Exam Full set — With tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — With tools Humanity's Last Exam Full set — With tools Effort: Medium Configuration: With tools 63.0% www-cdn.anthropic.com for Claude Opus 5.5 (medium) on Humanity's Last Exam Full set — With tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — With tools Humanity's Last Exam Full set — With tools Effort: High Configuration: With tools 63.9% www-cdn.anthropic.com for Claude Opus 5.5 (high) on Humanity's Last Exam Full set — With tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — With tools Humanity's Last Exam Full set — With tools Effort: xHigh Configuration: With tools 66.4% www-cdn.anthropic.com for Claude Opus 5.5 (xhigh) on Humanity's Last Exam Full set — With tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — With tools Humanity's Last Exam Full set — With tools Effort: Max Reported as: adaptive thinking, max; with tools Configuration: With tools 67.7% anthropic.com for Claude Opus 5.5 (adaptive thinking, max; with tools) on Humanity's Last Exam Full set — With tools (opens in a new tab) Humanity's Last Exam Accuracy Reported September 22, 2026 Launch post Anthropic Self-reported Record for Claude Opus 5.5 on Humanity's Last Exam Full set — With tools Humanity's Last Exam Text only — Mercor single-shot Effort: Max Configuration: Mercor single-shot agent 57.4% mercor.com for Claude Opus 5.5 (max) on Humanity's Last Exam Text only — Mercor single-shot (opens in a new tab) Archived copy (opens in a new tab) Humanity's Last Exam Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on Humanity's Last Exam Text only — Mercor single-shot MedXpertQA MM — Mercor single-shot Effort: Max Configuration: Mercor single-shot agent 85.7% mercor.com for Claude Opus 5.5 (max) on MedXpertQA MM — Mercor single-shot (opens in a new tab) Archived copy (opens in a new tab) Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on MedXpertQA MM — Mercor single-shot MMLU-Pro Original — Mercor single-shot Effort: Max Configuration: Mercor single-shot agent 93.4% mercor.com for Claude Opus 5.5 (max) on MMLU-Pro Original — Mercor single-shot (opens in a new tab) Archived copy (opens in a new tab) Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on MMLU-Pro Original — Mercor single-shot MMMU-Pro 1,730 questions — Mercor single-shot Effort: Max Configuration: Mercor single-shot agent 87.4% mercor.com for Claude Opus 5.5 (max) on MMMU-Pro 1,730 questions — Mercor single-shot (opens in a new tab) Archived copy (opens in a new tab) MMMU-Pro accuracy Setting: Not stated Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on MMMU-Pro 1,730 questions — Mercor single-shot MILU Original Effort: Max 93.1% www-cdn.anthropic.com for Claude Opus 5.5 (max) on Multi-task Indic Language Understanding Benchmark Original (opens in a new tab) Average accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Multi-task Indic Language Understanding Benchmark Original PostTrainBench 1.2 — Claude Code Effort: Max Configuration: Claude Code harness 43.8% posttrainbench.com for Claude Opus 5.5 (Max) on PostTrainBench 1.2 — Claude Code (opens in a new tab) Archived copy (opens in a new tab) PostTrainBench Weighted Aggregate Reported October 6, 2026 Benchmark leaderboard PostTrainBench Independent PostTrainBench Team Record for Claude Opus 5.5 on PostTrainBench 1.2 — Claude Code Riemann-bench October 2026 leaderboard Effort: Max Reported as: Adaptive/Max 69.6% surgehq.ai for Claude Opus 5.5 (Adaptive/Max) on Riemann-bench October 2026 leaderboard (opens in a new tab) Archived copy (opens in a new tab) Riemann-bench Pass@1 Reported October 7, 2026 Benchmark leaderboard Surge AI Independent Record for Claude Opus 5.5 on Riemann-bench October 2026 leaderboard SimpleQA Verified Original — Epoch AI harness Effort: Max Configuration: Epoch AI harness 72.2% epoch.ai for Claude Opus 5.5 (max) on SimpleQA Verified Original — Epoch AI harness (opens in a new tab) Archived copy (opens in a new tab) Accuracy Reported October 7, 2026 Evaluated September 22, 2026 at 6:27 PM UTC Benchmark leaderboard Epoch AI Independent Record for Claude Opus 5.5 on SimpleQA Verified Original — Epoch AI harness SWE Atlas Codebase QnA — Mercor mini-swe-agent, 250 steps Effort: Max Configuration: Mercor mini-swe-agent, 250 steps, 1 hour 48.9% mercor.com for Claude Opus 5.5 (max) on SWE Atlas Codebase QnA — Mercor mini-swe-agent, 250 steps (opens in a new tab) Archived copy (opens in a new tab) Mean pass@1 Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on SWE Atlas Codebase QnA — Mercor mini-swe-agent, 250 steps SWE-bench Multilingual Effort: Max 93.9% www-cdn.anthropic.com for Claude Opus 5.5 (max) on SWE-bench Multilingual (opens in a new tab) Resolved Tasks Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on SWE-bench Multilingual SWE-bench Multilingual — Mercor mini-swe-agent, 1000 steps Effort: Max Configuration: Mercor mini-swe-agent, 1000 steps, 3 hours 95.5% mercor.com for Claude Opus 5.5 (max) on SWE-bench Multilingual — Mercor mini-swe-agent, 1000 steps (opens in a new tab) Archived copy (opens in a new tab) Resolved Tasks Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on SWE-bench Multilingual — Mercor mini-swe-agent, 1000 steps SWE-bench Verified — Mercor mini-swe-agent, 1000 steps Effort: Max Configuration: Mercor mini-swe-agent, 1000 steps, 3 hours 98.2% mercor.com for Claude Opus 5.5 (max) on SWE-bench Verified — Mercor mini-swe-agent, 1000 steps (opens in a new tab) Archived copy (opens in a new tab) Resolved Tasks Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on SWE-bench Verified — Mercor mini-swe-agent, 1000 steps SWE-bench Pro Public Effort: Max 89.9% www-cdn.anthropic.com for Claude Opus 5.5 (max) on SWE-bench Pro Public (opens in a new tab) Public tasks resolved Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on SWE-bench Pro Public Terminal-Bench 4.0 Effort: xHigh 66.4% anthropic.com for Claude Opus 5.5 (xhigh) on Terminal-Bench 4.0 (opens in a new tab) Terminal-Bench Accuracy Reported September 22, 2026 Launch post Anthropic Self-reported Record for Claude Opus 5.5 on Terminal-Bench 4.0 Terminal-Bench 4.0 Effort: Max 64.8% www-cdn.anthropic.com for Claude Opus 5.5 (max) on Terminal-Bench 4.0 (opens in a new tab) Terminal-Bench Accuracy Reported September 22, 2026 System card Anthropic Self-reported Record for Claude Opus 5.5 on Terminal-Bench 4.0 Terminal-Bench 4.0 — Claude Code Effort: Max Configuration: Claude Code harness 64.9% tbench.ai for Claude Opus 5.5 (max) on Terminal-Bench 4.0 — Claude Code (opens in a new tab) Archived copy (opens in a new tab) Terminal-Bench Accuracy Reported September 22, 2026 Benchmark leaderboard Terminal-Bench Independent Terminal-Bench Team Record for Claude Opus 5.5 on Terminal-Bench 4.0 — Claude Code Terminal-Bench 4.0 — Mercor mini-swe-agent Effort: Max Configuration: Mercor mini-swe-agent, 1000 steps, 8 hours 58.3% mercor.com for Claude Opus 5.5 (max) on Terminal-Bench 4.0 — Mercor mini-swe-agent (opens in a new tab) Archived copy (opens in a new tab) Terminal-Bench Accuracy Reported October 7, 2026 Benchmark leaderboard Mercor Independent Record for Claude Opus 5.5 on Terminal-Bench 4.0 — Mercor mini-swe-agent Terminal-Bench Science 0.1 Effort: Max Reported as: adaptive thinking, max 58.7% anthropic.com for Claude Opus 5.5 (adaptive thinking, max) on Terminal-Bench Science 0.1 (opens in a new tab) Terminal-Bench Accuracy Reported September 22, 2026 Launch post Anthropic Self-reported Record for Claude Opus 5.5 on Terminal-Bench Science 0.1 Vibe Code Bench 1.1 — OpenHands, October 2026 evaluation Configuration: OpenHands harness 90.3% vals.ai for Claude Opus 5.5 on Vibe Code Bench 1.1 — OpenHands, October 2026 evaluation (opens in a new tab) Archived copy (opens in a new tab) Vibe Code Bench Score Reported October 6, 2026 Benchmark leaderboard Vals AI Independent Record for Claude Opus 5.5 on Vibe Code Bench 1.1 — OpenHands, October 2026 evaluation