GPT-5 Chat (latest)

OpenAIReasoning

openai/gpt-5-chat-latestClosed API

Chat-tuned GPT model for conversational assistance, writing, and tool workflows

Benchmark Pricing$1.25 / 1M in$10.00 / 1M out$0.13 cache read

Context: 400,000 tokens•Max Output: 128,000 tokens•Knowledge: 2024-09-30•Released: 2025-08-07

TECHNICAL SPECIFICATIONS

Context Window400,000400K tokens

Max Output128,000128K tokens

LicenseProprietaryCloud API only

Input Modalities

TextVision

Function / Tool CallingNot Supported

Structured OutputsPrompt Based

MODEL CONTEXT PROTOCOL (MCP) READINESS

⚠ GPT-5 Chat (latest) does not natively advertise tool-calling capabilities. When connecting to MCP servers, function calling must be handled via structured prompt injection.

MCP Context Window Recommendations

With a context capacity of 400,000 tokens, this model can handle moderately large MCP tool definitions and multi-turn conversation logs comfortably.

API CALL INVOCATION EXAMPLE

// Example: Calling GPT-5 Chat (latest) via OpenAI SDK
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.OPENAI_API_KEY,
});

const response = await client.chat.completions.create({
  model: "openai/gpt-5-chat-latest",
  messages: [{ role: "user", content: "Hello! Can you inspect MCP tools?" }],
});

console.log(response.choices[0].message.content);