You can’t use Astra. Here is what comes closest.

A committee of frontier models behind one prompt.

What it is

OpenRouter is a single API and chat interface in front of hundreds of models from every major lab. Its Fusion mode sends your prompt to several strong models in parallel and synthesizes one answer from the group.

What it shares with Astra

Astra’s announced direction is multiple agents working a problem together over a long horizon. Fusion is the nearest thing you can actually buy today: not one model’s first draft, but a reconciled answer from several. The mechanism is far simpler than what OpenAI describes — it is a structural echo, not an equivalent.

Best for

Hard questions where you would otherwise paste the same prompt into three chatbots and compare, and developers who want one key for every frontier model.

The honest limit

It does not sustain work over hours or days, and a committee of today’s models does not become Astra. It reduces single-model blind spots; it does not remove them.

The strongest single reasoning model you can use right now.

What it is

Anthropic’s current frontier model, generally available in the Claude apps and API. It is built for long, careful reasoning over large amounts of context, and for agentic work that runs tools over many steps.

What it shares with Astra

If Astra’s claim is “a model that stays with a hard problem,” this is the closest publicly available temperament: extended thinking, long documents, multi-step tool use. It has not solved open problems in mathematics, and no public model has.

Best for

Sustained analytical work: research synthesis, long documents, serious writing, and coding sessions that run for hours.

The honest limit

A single model, however strong, is still bounded by one context window and one session. The open-problem results Astra was announced with are not something you can reproduce by subscribing.

Where Astra’s capabilities will most likely surface first.

What it is

OpenAI’s shipping product, currently built around the GPT-5 family, with reasoning modes, agent features, and deep research tools.

What it shares with Astra

Astra is OpenAI’s own next family. Whatever OpenAI releases publicly — under the Astra name, as GPT-6, or otherwise — history says it lands in ChatGPT and the API first. Using ChatGPT today is the most direct way to be standing where the door will open.

Best for

General use, and anyone who wants to be on the platform Astra will almost certainly ship to.

The honest limit

Today’s ChatGPT is not Astra, and OpenAI has not said when, or in what form, Astra’s capabilities will reach it.

The other frontier lab’s answer, available now.

What it is

Google’s frontier model family, with long-context reasoning, deep research modes, and tight integration with Google’s products.

What it shares with Astra

Google is running the same race with a different bet. Its unrelated “Project Astra” assistant prototype shares nothing with OpenAI’s Astra but the name — a collision we cover separately.

Best for

Long-context research, multimodal work, and people already living in Google’s ecosystem.

The honest limit

Like every public model, it answers in minutes, not days. The name overlap with Google’s own Project Astra causes real confusion; check which “Astra” a headline means.