Claude Opus 5 (Fast) API AI Agent

Claude Opus 5 (Fast) Pricing

An AI agent workload (50K input + 5K output tokens, 100 tasks/day) costs approximately $875.76/month on Qubax.

Why use Claude Opus 5 (Fast) for AI agents on Qubax?

• 🤖Autonomous agents that call APIs and external tools
• 🤖Multi-step reasoning for complex task completion
• 🤖Agent orchestration with LangChain, CrewAI, or custom frameworks
• 🤖Function calling for structured, reliable agent responses

About Claude Opus 5 (Fast)

Claude Opus 5 (Fast) is a speed-optimized variant of Anthropic's most capable Opus model, offering the same 1M token context window and strong performance across agentic coding, professional knowledge work, and long-horizon reasoning with lower latency. It supports a 1M-token context window and up to 128K output tokens per request. Native capabilities include reasoning, vision, tool calling, structured output, streaming, context caching. On Qubax it is served by 295 independent sellers, so pricing stays competitive and uptime stays high.

Claude Opus 5 (Fast) AI Agent — code example

from openai import OpenAI
import json

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

tools = [{
    "type": "function",
    "function": {
        "name": "get_weather",
        "parameters": {"type": "object", "properties": {"city": {"type": "string"}}},
    },
}]

resp = client.chat.completions.create(
    model="claude-opus-5-fast",
    messages=[{"role": "user", "content": "What's the weather in Tokyo?"}],
    tools=tools,
)
call = resp.choices[0].message.tool_calls[0]
print(json.loads(call.function.arguments))  # -> {"city": "Tokyo"}

More Anthropic models on Qubax

Claude Opus 5 (Fast) AI Agent FAQ