Claude Opus 5.5
Claude Opus 5.5Alternatives?
CheaperGrok 4.7unstated-2%-63%$2 / $6Context: 1M → 500K+5
OpenGLM 5.3unstated-3%-73%$1.40 / $4.40No image input+5
CheaperMuse Spark 1.3unstated-2%-75%$1.25 / $4.25Only auto tool_choice is supported+5
CheaperGPT-6 Solunstated-2%-50%$2 / $10aCheaperAion 3.5unstated-3%-53%$3 / $6Context: 1M → 262K+2Grok 4.7unstated-2%-63%$2 / $6Context: 1M → 500K+5Muse Spark 1.3unstated-2%-75%$1.25 / $4.25Only auto tool_choice is supported+5GPT-6 Solunstated-2%-50%$2 / $10aAion 3.5unstated-3%-53%$3 / $6Context: 1M → 262K+2GLM 5.3unstatedOpen-3%-73%$1.40 / $4.40No image input+5GLM 5.3unstatedOpen-3%-73%$1.40 / $4.40No image input+5
Kimi K3unstatedOpen-6%-25%$3 / $15Sampling parameters are fixed+3Kimi K2.6unstatedOpen-7%-79%$0.95 / $4Context: 1M → 256KGLM 5.2unstatedOpen-8%-73%$1.40 / $4.40No image input+1
DeepSeek V4 Pro 0813unstatedOpen-11%-75%$1.32 / $3.96No image input+6Claude Opus 5unstated+2%—$5 / $25Claude Fable 5.1unstatedsame—$10 / $50Replace forced tool_choice+5Claude Fable 5unstated-2%—$10 / $50Claude Opus 4.7unstated-3%—$5 / $25Claude Opus 4.8unstated-4%—$5 / $25Claude Sonnet 4.6unstated-6%—$3 / $15Claude Sonnet 5unstated-7%—$2 / $10Claude Opus 4.6unstated-8%—$5 / $25All Anthropic models →History
9 versionsBenchmarks
in Writing & LanguageWatch 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 EQ-Bench Longform Creative Writing 1.11, Claude Opus 5.5 scores 84.6 vs 86.3 — lower.
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?›
Grok 4.7 (cheaper), GLM 5.3 (open weights).