Claude Opus 4.5 is Anthropic's frontier reasoning model released in November 2025, optimized for complex software engineering, agentic workflows, and long-horizon computer use. It offers strong multimodal capabilities, improved robustness to prompt injection, and a new effort parameter that lets developers trade off speed, depth, and token usage depending on task requirements. The model excels at autonomous research, multi-step debugging, spreadsheet and browser manipulation, and coordinated multi-agent setups, delivering substantial gains in structured reasoning and execution reliability.
Anthropic ProAnthropic Max (5x)Anthropic Max (20x)API|VisionReasoningWeb SearchFile|Proprietary Model
Knowledge Cutoff
2025-08-01
Input → Output Format
Context Memory
200KIN64KOUT
AI Performance Evaluation
Arena Overall Score
1473
±4As of 2026-04-23
Overall Rank
No.14
37,164 Votes
Arena by Ability
Hard Prompts
1500±5No.10
Expert Knowledge
1505±13No.10
Instruction Following
1485±7No.6
Conversation Memory
1487±8No.12
Creative
1468±9No.7
Coding
1531±7No.8
Math
1470±12No.14
Arena by Occupation
Creative Writing
1465±7No.9
Social Sciences
1489±8No.11
Media
1456±8No.10
Business
1468±8No.19
Healthcare
1489±13No.20
Legal
1487±12No.11
Software
1512±6No.11
Mathematics
1470±15No.19
Source:Arena Intelligence
Overall
AA Intelligence Index
50%↑11%
LiveBench
54%↓7%
ForecastBench
60%↑1%
Reasoning & Math
AA Math Index
91%↑18%
GPQA Diamond
87%↑5%
HLE
28%↑11%
MMLU-Pro
90%↑8%
AIME 2025
91%↑18%
LB Reasoning
48%↓12%
LB Math
64%↓9%
LB Data
44%↓5%
Coding
AA Coding Index
48%↑14%
LiveCodeBench
87%↑22%
LB Coding
78%↑5%
LB Agentic
50%↑7%
TAU2
90%↑16%
TerminalBench
47%↑16%
SciCode
50%↑9%
Language & Instructions
IFBench
58%↑1%
AA-LCR
74%↑12%
Hallucination (HHEM)
11%↑1%
Factual (HHEM)
89%↓1%
LB Language
77%↑5%
LB IF
29%↓17%
Output Speed
Standard Mode
51tok/s↓31
First Output 1.21s
Reasoning Mode
68tok/s↓20
First Output 10.52s
