Is GPT-5 available on FastMetal?

Not at the moment. GPT-5.6 Sol, from the same lab, is available on the FastMetal API today.

What is the context window of GPT-5?

400,000 tokens, shared between the prompt and the response.

#106 on the public arena's Japanese board (ELO 1,364). Ranks move as the leaderboard is updated.

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openai/gpt-5

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GPT-5

GPT-5 is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. It is optimized for complex tasks that require step-by-step reasoning, instruction following, and accuracy in high-stakes use cases. It supports test-time routing features and advanced prompt understanding, including user-specified intent like "think hard about this." Improvements include reductions in hallucination, sycophancy, and better performance in coding, writing, and health-related tasks.

8/7/2025

400,000 tokens

#103 Vision (Overall)

Specifications

Modalities

Input

text

image

file

Output

text

Supported Parameters

include_reasoning

max_tokens

reasoning

response_format

seed

structured_outputs

tool_choice

tools

Max Output Tokens

128,000

Reasoning Configuration

Default: Thinking on (effort: medium)
Selectable effort levels: high
medium
low
minimal
Turning thinking off: Not possible (always thinks)

How to control thinking, and what it costs

Frequently asked questions

Is GPT-5 available on FastMetal?: Not at the moment. GPT-5.6 Sol, from the same lab, is available on the FastMetal API today.
What is the context window of GPT-5?: 400,000 tokens, shared between the prompt and the response.
How does GPT-5 rank?: #106 on the public arena's Japanese board (ELO 1,364). Ranks move as the leaderboard is updated.