# GPT-6.1 Terra

> GPT-6.1 Terra was released by OpenAI on October 26, 2026. OpenAI's GPT-6 model guide features four models: Astra, 6.1 Sol, 6.1 Terra and GPT-6 Luna. Terra is labeled fast and efficient, aimed at visual reasoning, precise computer use and clear, natural writing; OpenAI's examples include matching product photos to catalog entries, comparing technical drawings and acting on application screens.

Canonical: https://routemux.com/openai/gpt-6.1-terra
Provider: OpenAI

## Key facts

| Field | Value |
| --- | --- |
| Model ID | openai/gpt-6.1-terra |
| Official model ID | gpt-6.1-terra |
| Context window | 1.05M |
| Max output | 128K |
| Input modalities | text, image |
| Output modalities | text |
| Capabilities | Vision, Reasoning, Tool Calling, Coding, Cache, Paid Cache Write |
| Upstream release | 2026-10-26 |
| Availability | available |

## Pricing

- RouteMux input: $0.15 per 1M tokens
- RouteMux output: $0.75 per 1M tokens
- Official input: $1 per 1M tokens
- Official output: $5 per 1M tokens
- Cache read: $0.0075 per 1M tokens
- Cache write: $0.1875 per 1M tokens
- Saving vs official: 85%

Billing is prepaid wallet, charged per successful request only.

## API access

Base URL: https://api.routemux.com

Supported protocols:

- openai_chat
- openai_responses
- anthropic_messages

## What is GPT-6.1 Terra

GPT-6.1 Terra was released by OpenAI on October 26, 2026. OpenAI's GPT-6 model guide features four models: Astra, 6.1 Sol, 6.1 Terra and GPT-6 Luna. Terra is labeled fast and efficient, aimed at visual reasoning, precise computer use and clear, natural writing; OpenAI's examples include matching product photos to catalog entries, comparing technical drawings and acting on application screens.

The specs: a 1.05M-token context window (up to 922K input), 128K max output, text and image in, text out, and a knowledge cutoff of June 1, 2026. Reasoning effort takes none, low, medium, high, xhigh or max, with medium as the default; unlike Astra and 6.1 Sol it accepts none, so reasoning can be switched off. On RouteMux it supports tool calling and explicit prompt caching, and it is reachable over OpenAI Chat Completions, OpenAI Responses and Anthropic Messages.

When to stay on GPT-5.6 Terra: one conversation moves between GPT-5.6 Sol, Terra and Luna and should keep its reasoning (OpenAI's reasoning guide documents reuse across the three 5.6 tiers and does not list 6.1 Terra), or your prompts and evals were tuned against 5.6 Terra. For the move itself, OpenAI suggests running both models on representative images and workflows at the same reasoning effort.

At the standard tier (input up to 272K tokens) it bills $0.15 per 1M input tokens and $0.75 per 1M output tokens, with cached input at $0.0075 per 1M tokens. OpenAI lists $1, $5 and $0.05 for the same three.

## Key capabilities

- **Built for visual work and computer use** — OpenAI positions it for visual reasoning, precise computer use and clear, natural writing, with examples like matching product photos to catalog entries.
- **Reasoning can be turned off** — reasoning_effort takes none through max, defaulting to medium. GPT-6 Astra and 6.1 Sol reject none; 6.1 Terra accepts it.
- **Knowledge cutoff June 1, 2026** — About three and a half months later than GPT-5.6 Terra's February 16; the 1.05M context and 128K output match 5.6 Terra.

## Other variants in this family

- GPT-6 Astra (`openai/gpt-6-astra`)
- GPT-6.1 Sol (`openai/gpt-6.1-sol`)
- GPT-6 Sol (`openai/gpt-6-sol`)
- GPT-6 Luna (`openai/gpt-6-luna`)

## Sources

- [OpenAI — GPT-6.1 Terra model page](https://developers.openai.com/api/docs/models/gpt-6.1-terra)
- [OpenAI — Using GPT-6 (model guide)](https://developers.openai.com/api/docs/guides/latest-model)
- [OpenAI — Reasoning models guide](https://developers.openai.com/api/docs/guides/reasoning)
- [OpenAI — API changelog](https://developers.openai.com/api/docs/changelog)