# GPT-6 Astra

> OpenAI's GPT-6 flagship. 1.05M context, image input, reasoning; the rate doubles above 272K prompt tokens.

Human version: https://kymaapi.com/models/gpt-6-astra
Live JSON: `GET https://kymaapi.com/v1/models` (no auth required)

## Facts

- **Model ID**: `gpt-6-astra`: pass this as `model` in the request body
- **Creator**: OpenAI
- **Released**: 2026-09-04
- **Context window**: 1M tokens
- **Max output**: 128K tokens per response, a hard ceiling, not a default
- **Price**: $13.50 in / $67.50 out per 1M, cached input $1.35 per 1M
- **Capabilities**: tools, vision, reasoning, caching

## Call it

```bash
curl https://kymaapi.com/v1/chat/completions \
  -H "Authorization: Bearer $KYMA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-6-astra", "messages": [{"role": "user", "content": "Hello"}]}'
```

## Positioning

GPT-6 Astra is OpenAI's GPT-6 flagship for the hardest reasoning and long-horizon agentic work. Reach for it when a task needs the strongest OpenAI model available and a 1.05M-token window.

## About

GPT-6 Astra went GA on 2026-09-04. OpenAI's model page lists a 1,050,000-token context window, 128,000 max output tokens, an April 30, 2026 knowledge cutoff and reasoning token support. Text is input and output; images are input only; audio and video are not supported.

On Kyma it is served through the OpenAI-compatible endpoint with exact cost reporting in the usage.cost field. Prompt caching is supported at this model's cached input rate. The rate doubles above 272K prompt tokens, exactly as OpenAI prices it.

It is a closed model available by API only. It is the successor to GPT-5.6 Sol in OpenAI's line-up and is priced above it.

## Use cases

- **Hardest reasoning**, Multi-step analysis, proofs and planning where the strongest OpenAI model is the point.
- **Long-horizon agents**, A 1.05M-token window and 128K output cap keep long agent sessions in one context.
- **Document and image understanding**, Image input plus the long window for contracts, decks and screenshots.

## Not ideal for

Cost-sensitive or high-volume traffic — this is a flagship rate, and prompts above 272K tokens bill at twice it.

## Pick something else when

- You want the previous OpenAI flagship at a lower rate → `gpt-5.6-sol`
- You want the best general default overall → `qwen-3.6-plus`

## See also

- All models: https://kymaapi.com/models.md
- Pricing: https://kymaapi.com/pricing.md
- Other models by OpenAI: https://kymaapi.com/models?q=OpenAI