Claude Opus 4.6 API

Overview

Claude Opus 4.6 is Anthropic's most capable model, built for hard problems: complex refactors, multi-step agents, deep analysis, and research-grade reasoning. When output quality matters more than cost, this is the model you reach for.

What Claude Opus 4.6 is best for

• Hard code refactors and architecture work
• Long-horizon autonomous agents
• Research, analysis, and technical writing
• Tasks where a wrong answer is expensive
• 🧠 Extended thinking available

Strengths and tradeoffs

Strengths: Best-in-class reasoning and instruction following, strong on code, 200K context, extended thinking support.

Tradeoff: Highest price per token. For simple or high-volume tasks, Sonnet or Haiku is usually the smarter spend.

Pricing

Estimate your own usage with the API cost calculator or count tokens with the token counter.

Quick start (Python)

Claude Opus 4.6 runs through KissAPI's OpenAI-compatible endpoint, so any OpenAI SDK works. Just change the base URL and model id:

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_KISSAPI_KEY",
    base_url="https://api.kissapi.ai/v1",
)

resp = client.chat.completions.create(
    model="claude-opus-4-6",
    messages=[{"role": "user", "content": "Explain async/await in one paragraph."}],
)
print(resp.choices[0].message.content)

Works with Cursor, Claude Code, Cline, Aider, and any OpenAI-compatible client.

Frequently asked questions

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