Claude Opus 5.5
Claude Opus 5.5Alternatives?
CheaperGPT-6.1 Solmax+7%-46%$0.72Remove unsupported parameters+5
OpenGLM 5.3max-20%+50%$2.01No image input+5Lower effortSame modellow-40%-59%$0.55CheaperClaude Sonnet 5.5high-16%-34%$0.88No forced tool use+5CheaperGPT-6 Solmax-16%-22%$1.04GPT-6.1 Solmax+7%-46%$0.72Remove unsupported parameters+5Claude Sonnet 5.5high-16%-34%$0.88No forced tool use+5GPT-6 Solmax-16%-22%$1.04GPT-6.1 Solmax+7%-46%$0.72Remove unsupported parameters+5
Gemini 4 Argonhigh+9%+49%*$1.99Synchronous output stops at 65,536+2Claude Sonnet 5.5xhigh+9%+51%$2.01No forced tool use+5GPT-6 Astraxhigh+13%+73%$2.31Monitoring can return HTTP 403+2Claude Fable 5.1xhigh+5%+347%$5.98Replace forced tool_choice+5GLM 5.3maxOpen-20%+50%$2.01No image input+5
MiMo v2.6 ProthinkingOpen-34%-90%$0.13No PDF input+4
DeepSeek V4.1 Flash 1017maxOpen-36%-80%$0.26No PDF input+5
Ling 3.1 FlashOpen-37%-25%$1.00No image input+1
Step 5 PreviewthinkingOpen-37%-23%$1.03No PDF input+4Claude Fable 5.1medium-14%+123%$2.98Replace forced tool_choice+5Claude Fable 5max-19%+555%$8.75Claude Opus 5medium-35%+64%$2.19Claude Sonnet 5.5medium-43%-64%$0.48No forced tool use+5Claude Opus 4.8max-59%+205%$4.08Claude Haiku 5.5medium-71%-96%$0.047Remove sampling parameters+5Claude Sonnet 4.6max-94%+86%$2.49Claude Sonnet 5medium-96%-25%$1.00All Anthropic models →History
9 versionsBenchmarks
in CodingWatch out 6
No forced tool use›
Forced tool_choice any or tool returns HTTP 400; remove the forced choice. Source ↗
Thinking is always on›
Disabled thinking or a manual budget returns HTTP 400; omit thinking or use adaptive thinking. Source ↗
Remove sampling parameters›
Non-default temperature, top_p or top_k returns HTTP 400; omit these parameters and use prompting. Source ↗
No assistant prefill›
Assistant prefill returns HTTP 400; use structured outputs or system instructions, with system instructions on Bedrock. Source ↗
Old computer tool rejected · Claude API / Google Cloud›
The computer_20251124 tool returns HTTP 400 on the Claude API and Google Cloud; use computer_toolset_20260801 there. Source ↗
Return thinking blocks unmodified›
Edited, reordered or partially dropped thinking blocks return HTTP 400; echo assistant messages complete and unmodified with tool results. Source ↗
FAQ
How much does Claude Opus 5.5 cost?›
$4 per 1M input tokens and $20 per 1M output tokens; cached input $0.20 per 1M. A typical benchmark task costs about $1.34 at medium effort.
Is Claude Opus 5.5 free to use?›
There is no free API; the cheapest paid price is $4 per 1M input tokens.
How good is Claude Opus 5.5, and what is it best at?›
#6 of 334 in Chat & Knowledge, #7 of 132 in Coding, #15 of 133 in Agents & Tool Use, #1 of 195 in Writing & Language, #3 of 124 in Vision & Documents. Strongest at: Coding, Agents & work tasks, Reasoning, Long context, Knowledge, Vision.
Is Claude Opus 5.5 better than Claude Opus 5?›
On Terminal-Bench 4.0, Claude Opus 5.5 scores 59.6 vs 49 — higher. It is 77% cheaper per task.
How can I use Claude Opus 5.5?›
Through the API of Amazon Bedrock, Anthropic, Azure, Claude Platform on AWS, DeepInfra and 1 more.
What is the context window of Claude Opus 5.5?›
1M tokens, with up to 128K output tokens.
When was Claude Opus 5.5 released? Is there a newer version?›
Released 2026-09-22. It is the current version in its line.
Is Claude Opus 5.5 open source?›
No, Claude Opus 5.5 is a closed model available through an API. The closest open-weights option here is GLM 5.3.
Can Claude Opus 5.5 read images?›
It accepts text and images, PDF files as input.
What is Claude Opus 5.5?›
Claude Opus 5.5 is a closed language model from Anthropic, released Sep 2026, the successor to Claude Opus 5.
What are the best alternatives to Claude Opus 5.5?›
GPT-6.1 Sol (cheaper), GLM 5.3 (open weights).