GPT-5.6 Terra

GPT-5.6 Terra is a balanced model from OpenAI for capable, cost-efficient everyday work. It is the first version of the gpt-terra line, released on 2026-07-09. It has a context window of 1,050,000 tokens and a maximum output of 128,000 tokens. Pricing starts at $1.50 per million input tokens and $2.00 per million output tokens, with cached input at $0.15 per million tokens. The weights are not open. It supports reasoning mode, tool calling, and accepts image, PDF, and text input, returning text. Knowledge cutoff is 2026-02-16.

First version of its line in the registry.

Range across the hosts that serve it: up to $4.00 per 1M input tokens.

• ·1.05M token context window
• ·128K max output tokens
• ·From $1.50 per M input tokens
• ·Supports reasoning and tool calling
• ·Accepts image, PDF, and text input

• Reach for it for processing long documents up to 1.05M tokens
• Reach for it for cost-sensitive workloads using cached input
• Reach for it for tasks needing reasoning and tool calls
• Reach for it for mixed image and text inputs

31 hosts serve this model at the price above · the maker's documentation

• 9那个教 ChatGPT 说话的人，做了一个「哑巴」模型2026-09-19

1 signal of the archive mention this model, each scored against the published bar. This list is rebuilt from the archive at every build, so it cannot go stale.

The registry keeps the six most recent versions of a line. Older ones stay in the file and can be surfaced without a rebuild.

What is the context window?

The context window is 1,050,000 tokens.

What does it cost?

Input from $1.50 per million tokens, output from $2.00 per million, cached input from $0.15 per million.

Are the weights open?

No, the weights are not open.