anthropic/claude-opus-4-6

Claude Opus 4.6

Name: Claude Opus 4.6
Brand: Anthropic
Availability: InStock

Opus 4.6 is Anthropic’s strongest model for coding and long-running professional tasks. It is built for agents that operate across entire workflows rather than single prompts, making it especially effective for large codebases, complex refactors, and multi-step debugging that unfolds over time. The model shows deeper contextual understanding, stronger problem decomposition, and greater reliability on hard engineering tasks than prior generations. Beyond coding, Opus 4.6 excels at sustained knowledge work. It produces near-production-ready documents, plans, and analyses in a single pass, and maintains coherence across very long outputs and extended sessions. This makes it a strong default for tasks that require persistence, judgment, and follow-through, such as technical design, migration planning, and end-to-end project execution. For users upgrading from earlier Opus versions, see our [official migration guide here](https://openrouter.ai/docs/guides/guides/model-migrations/claude-4-6-opus)

2/4/2026

1,000,000 tokens

#2 Text (spanish)

Input: ¥850/M

Output: ¥4,200/M

Try in Chat Get API Key

Specifications

Modalities

Input

text

image

Output

text

Supported Parameters

include_reasoning

max_tokens

reasoning

response_format

stop

structured_outputs

temperature

tool_choice

tools

top_k

top_p

verbosity

Max Output Tokens

128,000

Code Examples

curl https://api.fastmetal.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "anthropic-claude-opus-4-6",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

How Claude Opus 4.6 actually answers

Real responses to our standard prompts, recorded on FastMetal.

Count the number of 'r's in 'strawberry'

Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.

I need to count the number of 'r's in the word 'strawberry'. Let me go through it letter by letter. **s** - not an r **t** - not an r **r** - this is an r ✓ (count: 1) **a** - not an r **w** - not an r **b** - not an r **e** - not an r **r** - this is an r ✓ (count: 2) **r** - this is an r ✓ (count: 3) **y** - not an r There are **3** r's in 'strawberry'.

3.2s response158 output tokens

Debug This Error

I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…

# Understanding the Error The error `Cannot read properties of undefined (reading 'map')` means that **`users` is `undefined`** when the component renders. You're trying to call `.map()` on a value that doesn't exist yet. This typically happens when: - The parent component doesn't pass the `users` prop - The data is being fetched asynchronously and hasn't loaded yet - The prop name is misspelled ## Solutions ### 1. Add a Default Parameter Value (Simplest Fix) ```javascript function UserList({ users = [] }) { return ( <ul> {users.map(user => <li key={user.id}>{user.name}</li>)} </ul> ); } ``` ### 2. Add a Guard with Optional Chaining ```javascript function UserList({…

10.5s response599 output tokens

Code Review

Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…

# Code Review: `get_data` Function ## Original Issues Identified 1. **Imports inside function** – reduces clarity and adds per-call overhead 2. **Bare `except`** – catches everything including `KeyboardInterrupt` and `SystemExit` 3. **`== True` comparison** – non-Pythonic 4. **Manual list building** – could use a list comprehension 5. **No logging** – failures happen silently 6. **No response validation** – assumes JSON is always a list of dicts with specific keys 7. **Magic numbers** – `timeout=10`, `sleep(2)` unexplained 8. **Vague function/variable names** – `r`, `data`, `get_data` --- ## Improved Version ```python import logging import time from typing import Any import requests fr…

19.9s response1223 output tokens

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Leaderboard

Text

🏆OverallELO: 1,497

🇯🇵JapaneseELO: 1,485

#11

🇨🇳ChineseELO: 1,549

🇰🇷KoreanELO: 1,458

🇬🇧EnglishELO: 1,507

frenchELO: 1,495

#20

germanELO: 1,493

spanishELO: 1,503

russianELO: 1,509

💻CodingELO: 1,548

🧮MathELO: 1,503

✍️Creative WritingELO: 1,477

📝Instruction FollowingELO: 1,499

🌶️Hard PromptsELO: 1,526

💬Multi-TurnELO: 1,512

Vision

🏆OverallELO: 1,294

Code

🏆OverallELO: 1,538

#15