anthropic/claude-sonnet-4-5-20250929Closed APIBalanced Claude model for coding, analysis, agent workflows, and cost control
TECHNICAL SPECIFICATIONS
MODEL CONTEXT PROTOCOL (MCP) READINESS
✓ Claude Sonnet 4.5 natively supports OpenAI / Anthropic format tool calling and is fully compatible with MCP servers and agent loops.
MCP Context Window Recommendations
With a context capacity of 200,000 tokens, this model can handle moderately large MCP tool definitions and multi-turn conversation logs comfortably.
API CALL INVOCATION EXAMPLE
// Example: Calling Claude Sonnet 4.5 via OpenAI SDK
import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.ANTHROPIC_API_KEY,
});
const response = await client.chat.completions.create({
model: "anthropic/claude-sonnet-4-5-20250929",
messages: [{ role: "user", content: "Hello! Can you inspect MCP tools?" }],
});
console.log(response.choices[0].message.content);PRICING BY PROVIDER
Rates in USD per 1M tokens. Rates synchronized from models.dev public catalog.
This model supports prompt caching at $0.30 / 1M tokens, saving up to 90% on repetitive MCP tool definitions and system instructions.
MODEL RESOURCES
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