Claude Opus 5.5
Claude Opus 5.5 is a flagship model developed by Anthropic designed for complex reasoning and long-horizon tasks. It supports large-scale data processing with a one-million-token context window and can interpret both text and image inputs.
Claude Opus 5.5 specs and pricing
- Provider: Anthropic
- Released: September 22, 2026
- Context window: 1M tokens
- Max output: 128K tokens
- Input: text, images, files
- Output: text
- Price: $4.00 input / $20 output per 1M tokens
- Reasoning: yes
- Tool calling: yes
What Claude Opus 5.5 is good at
- Complex coding projects involving multi-step changes
- Analyzing and synthesizing information from large document sets
- Executing long-horizon agentic workflows
To-dos to try with Claude Opus 5.5
- Analyze a large codebase to identify and refactor deprecated function patterns across multiple files.
- Upload a series of technical reports and summarize the core findings across all documents.
- Use tool calling to automate a multi-step research task based on provided file inputs.
FAQ
- Who developed Claude Opus 5.5? This model was developed by Anthropic as the successor to Claude Opus 5.
- Can this model process images? Yes, Claude Opus 5.5 is capable of accepting both text and image inputs.
- How much does Claude Opus 5.5 cost? Claude Opus 5.5 costs $4.00 per million input tokens and $20 per million output tokens through OpenRouter. In todo.is a typical agent step costs about 14 credits ($1 = 100 credits).
- What is the context window of Claude Opus 5.5? Claude Opus 5.5 can read up to 1M tokens at once and write up to 128K tokens in one reply.
- Can I use Claude Opus 5.5 without coding? Yes. In todo.is you pick Claude Opus 5.5 as your agent's model and write to-dos in plain words, on the web, the Android app, WhatsApp or Telegram. No API key needed: credits are included, or you can bring your own key.
JavaScript is required to use the todo.is app.