GPT-6.1 Terra
Knows up to June 2026Missing 1,795 events
gpt-6.1-terra
$1 in, $5 out per 1M tokens
GPT-6 Luna
High-volume classification, extraction, routing, sub-agents.
Model idgpt-6-luna
Price$0.10 in, $0.50 out per 1M tokens
Checked8 October 2026
Knows up to May 2026
1,829events after its cutoff
82 historic, 419 major. 166 days of news.
It launched on 22 September 2026, already missing 406 of them.
How to call it
4 ways to use GPT-6 Luna, with the model id each provider expects.
| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| OpenAI API | gpt-6-luna |
https://api.openai.com/v1/responses |
developers.openai.com |
| Azure OpenAI (Microsoft Foundry) | gpt-6-luna |
learn.microsoft.com | |
| OpenRouter | openai/gpt-6-luna |
openrouter.ai | |
| Web app | chatgpt.com |
Pricing
| Input | $0.10 per 1M tokens |
|---|---|
| Cached input | $0.01 per 1M tokens |
| Output | $0.50 per 1M tokens |
| Cache write | $0.125 per 1M tokens |
As published: “per 1M tokens (USD), standard tier”.
Source: developers.openai.com, checked 8 October 2026.
Specs
- Input
- Text and images
- Output
- Text
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
- Open weights
- No
- Licence
- Proprietary
- Training cutoff
- May 2026
- Released
- 22 September 2026
- Status
- Current
- Type
- Reasoning model
What stands out
What its maker marketed at launch, and what people found later, each with its source.
1M context at $0.10/M
Cheapest OpenAI reasoning model with the full 1.05M context window and 128K output.
Agentic tools on the budget tier
Supports computer use, hosted shell, MCP and tool search like the larger models.
Free-tier ChatGPT model
Rolled out to ChatGPT free users and the desktop app at launch.
Decisions API model
Found after launch
Only model behind OpenAI’s Decisions API (POST /v1/decisions, public beta since 2026-10-06): typed predicate/choice/score answers from text and images, about 10x faster than the Responses API, billed at $0.10 per 1M input tokens with no output charge.
Intelligent UI in ChatGPT (October 2026 update)
Found after launch
On Oct 7 2026 an October update of this model replaced GPT-5.6 in the ChatGPT Chat tab for Free and Go users; it composes answers with native streamable UI components (charts, maps, forms, buttons, calculators, small games) and can start answering while still thinking. The API and Codex/Work keep the September version; the chat-latest snapshot tracks the ChatGPT model.
Four assistants, one scale
GPT-6 Luna is added as a fifth row. Each row runs from what the model knows (graphite) through the months between its cutoff and its launch (hatched) to today (pink).
- GPT-6 Astra 271 at launch, 1,863 today
- Claude Opus 5.5 372 at launch, 1,795 today
- Gemini 4 Hydrogen 1,863 at launch, 1,889 today
- Grok 4.7 387 at launch, 1,829 today
- GPT-6 Luna 406 at launch, 1,829 today
Show as a table
| Model | Cutoff | Released | Missing at launch | Missing today |
|---|---|---|---|---|
| GPT-6 Astra | April 2026 | 3 September 2026 | 271 | 1,863 |
| Claude Opus 5.5 | June 2026 | 22 September 2026 | 372 | 1,795 |
| Gemini 4 Hydrogen | March 2026 | 12 November 2026 | 1,863 | 1,889 |
| Grok 4.7 | May 2026 | 21 September 2026 | 387 | 1,829 |
| GPT-6 Luna | May 2026 | 22 September 2026 | 406 | 1,829 |
Notes
Most efficient GPT-6 model for focused, high-volume tasks; successor to GPT-5.6 Luna (the mini/nano tier). OpenRouter also lists openai/gpt-6-luna-pro.
curl https://api.openai.com/v1/responses \
-H "Authorization: Bearer $OPENAI_API_KEY" -H "Content-Type: application/json" \
-d '{"model":"gpt-6-luna","input":"Hello"}'
Sources: