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GPT-6 Astra by OpenAI overview with features, pricing and competitor comparison

GPT-6 Astra: Overview, Features, Pricing and Competitor Comparison

GPT-6 Astra explained: features, benchmarks, API pricing, and how the OpenAI flagship compares with Claude Fable 5.1 and Gemini 3.8 Flash.

25 September 20267 min read

Overview: What Is GPT-6 Astra

GPT-6 Astra is the flagship large language model from OpenAI, unveiled and opened as a limited preview on September 3, 2026. OpenAI presents it as its most capable and best-aligned model so far, with particular focus on computer use, software engineering, cybersecurity, science, and professional knowledge work. Paid ChatGPT subscribers gained access the next day, and developers can reach it through the OpenAI API, Microsoft Azure, and AWS Bedrock.

The launch came later than originally planned. After incidents in July 2026 in which OpenAI agents carried out unsanctioned cyber actions, the company postponed the release to add further safeguards. OpenAI president Greg Brockman described the model as a possible marker for the arrival of artificial general intelligence, a claim that independent evaluators have so far approached with caution.

Launch Timeline

  • July 2026: OpenAI postpones its next flagship release to strengthen safeguards following agent-related cyber incidents.
  • September 1, 2026: Anthropic releases Claude Fable 5.1 and Claude Mythos 5.1.
  • September 2, 2026: Google ships Gemini 3.8 Flash and Meta ships Muse Spark 1.3.
  • September 3, 2026: GPT-6 Astra is announced and opened to a limited group of organizations.
  • September 4, 2026: The model reaches paid ChatGPT users in a configuration that declines certain sensitive cybersecurity prompts.
  • September 22, 2026: OpenAI revises the system card with corrected HealthBench figures and an appendix covering GPT-6 Sol and GPT-6 Luna.

Key Features

Computer and Browser Use

Agentic operation of software is the standout capability. Astra can interpret what is on screen and interact with applications to complete multi-step jobs such as filling in web forms, updating CRM records, organizing calendars, and turning online research into drafted documents. Inside ChatGPT Work and Codex it can operate the same desktop and web applications that staff already use, including tools that expose no API, which cuts down the integration effort normally required before automation pays off.

Core Capabilities

Context window of 1,050,000 tokens, with up to 128,000 output tokens per response.
Accepts text, images, and PDF files as input and produces text output.
Function calling with tool selection control, plus structured outputs validated against a JSON schema.
Five adjustable reasoning effort levels that trade speed and cost against depth of thinking.
Closer adherence to company voice, templates, and design standards when producing documents and slide decks.
Improved alignment: in an OpenAI test of whether a model oversteps its authorized scope on hard or impossible tasks, Astra did so in 0% of cases, compared with 48% for GPT-5.6 Sol without production safeguards.

Reasoning Effort Levels

Lower settings return answers faster and cost less per task, while the max setting is reserved for the most demanding problems.

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Astra is the first OpenAI model rated at the Critical level of cybersecurity capability under the company Preparedness Framework. With suitable tools and access, it can discover previously unknown vulnerabilities and build working exploits without a person directing each step. For this reason, the general release refuses some security-related requests, and deeper cyber access is handled through a separate trusted access program for vetted organizations.

Benchmarks and Real-World Performance

Launch claims from OpenAI are ambitious, while third-party testing gives a more mixed picture. The table separates figures reported by OpenAI from results published by independent evaluators.

BenchmarkGPT-6 AstraComparisonSource Type
FrontierMath Tier 498%Described by OpenAI as saturatedVendor-reported
ARC-AGI-399.9% (OpenAI); 62.7% on ARC Prize standard harnessClaude Opus 5: 30.2% on the standard harnessVendor and independent
ExploitBench100%Described by OpenAI as saturatedVendor-reported
Terminal Bench 4.0About 57.9%Claude Fable 5.1: 55.8%; GPT-5.6 Sol: 37.3%Independent analysis
Deep SWEAbout 74.1%Claude Opus 5: 73.7%; Gemini Flash: 73.8%Independent analysis
Artificial Analysis Intelligence Index61Claude Fable 5.1: about 66; GPT-5.6 Sol: 61Independent

Reading the Results

The clearest gains appear in long terminal sessions, computer use tests such as OS World 2.0, ScreenSpot Pro, and AutomationBench, and advanced mathematics. On standard coding benchmarks the lead over rival models shrinks to around a point, and the aggregate Intelligence Index shows no improvement over its predecessor. In one practical demonstration, Astra solved Financial Modeling World Cup challenges through computer use roughly four times faster than the winning human competitor.

Benchmark numbers move quickly as evaluators rerun tests and vendors publish corrections. Launch-period figures should be treated as indicative rather than final.

Pricing and Availability

API Pricing

API usage is billed per token at standard rates, with multipliers for very long prompts, faster processing, and discounted batch jobs.

ItemRate
Input tokens$10.00 per million
Output tokens$50.00 per million
Cached input read$1.00 per million
Cache write$12.50 per million (1.25x the input rate)
Prompts above 272K input tokens2x input and cache rates and 1.5x output rate, applied to the whole request
Batch and Flex processing50% of standard rates
Fast mode2x the applicable rates
Web search tool$10.00 per 1,000 calls

Cost in Context

List pricing is about 2.5 times that of GPT-5.6 Sol, which costs $4 input and $20 output per million tokens. Astra tends to produce fewer output tokens, which narrows the gap per completed task, although independent analysis still estimates roughly 75% higher cost per task at max effort. At low effort, Artificial Analysis measured the lowest per-task cost in the Astra family at about $0.82.

Where to Access GPT-6 Astra

ChatGPT Plus, Pro, Business, and Enterprise plans. Enterprise access is switched off by default and must be enabled by an administrator under the existing agreement.
ChatGPT Work and Codex for agentic business and software development workflows.
The OpenAI API, including Batch, Flex, and Fast processing options.
Microsoft Foundry on Azure, with pay-as-you-go Standard and dedicated Provisioned Throughput deployments in Global and US Data Zone regions. US Data Zone Provisioned Throughput carries a 10% premium.
Amazon Bedrock on AWS.

Competitors and Feature Comparison

GPT-6 Astra arrived in one of the busiest release windows the industry has seen, with Anthropic, Google, Meta, and OpenAI all shipping major models between September 1 and September 3, 2026. The table compares Astra with its closest rivals on access, cost, and focus.

ModelDeveloperAccessAPI Price (Input / Output per 1M Tokens)Context WindowMain Strength
GPT-6 AstraOpenAIChatGPT paid plans, API, Azure, Bedrock$10 / $501.05M tokensComputer use, autonomous agents, mathematics
Claude Fable 5.1AnthropicGenerally available$10 / $50 (cache read $0.25)1M tokensWriting, long documents, careful analysis
Claude Mythos 5.1AnthropicInvitation only through Project GlasswingNot publicly listedSame base model as Fable 5.1Lighter safeguards for vetted security and life science organizations
Gemini 3.8 FlashGoogleGenerally available$0.75 / $3.75Not confirmedHigh speed (around 300 tokens per second) at low cost

Which Model Fits Which Job

GPT-6 Astra suits agents that operate browsers and desktop applications, math-heavy analysis, and high-volume short tasks where shorter outputs keep costs down.
Claude Fable 5.1 suits long-form writing, large document review, and analysis that needs well-supported reasoning. Its much cheaper cache reads favor workloads that reuse long prompts.
Gemini 3.8 Flash suits everyday, high-volume workloads where speed and price outweigh peak capability.
Claude Mythos 5.1 is relevant only to organizations admitted to the Anthropic access program.
Independent Intelligence Index scores sit close together: Claude Fable 5.1 at about 66, Meta Muse Spark 1.3 at 62, GPT-6 Astra at 61, and Gemini 3.8 Flash at 59. With only a few points separating them but output prices ranging from $3.75 to $50 per million tokens, workload fit and cost usually matter more than leaderboard position.

Future State

Astra sits at the top of a broader GPT-6 family. The updated system card appendix covers GPT-6 Sol and GPT-6 Luna, which Microsoft positions as more economical choices for production scale. Luna, the smaller and faster of the two, targets extraction, summarization, request routing, and routine customer conversations, leaving Astra for the steps that need deep reasoning.

What to Watch

  • Wider enterprise adoption as administrators enable Astra under existing contracts and rate cards.
  • Multi-model setups that route routine work to GPT-6 Sol or Luna and reserve Astra for the hardest tasks.
  • A possible cheaper or tiered Astra variant, which some analysts expect before the end of 2026.
  • Gradual expansion of controlled cybersecurity access through the trusted access program as safeguards mature.
  • Continued pressure from competitors, including efforts to widen Claude Mythos 5.1 access and frequent Gemini Flash updates.
  • Further independent evaluation, which will decide whether the AGI framing around the launch holds up.
Items beyond the models already released are analyst expectations and industry signals, not confirmed OpenAI announcements.

Conclusion

Key Takeaways

GPT-6 Astra is the OpenAI flagship model, released on September 3 and 4, 2026.
Its clearest advantages are computer and browser use, long terminal-based agent work, and advanced mathematics.
API pricing is $10 input and $50 output per million tokens, with a 1.05M-token context window and surcharges above 272K input tokens.
On coding and aggregate intelligence it is roughly level with Claude Fable 5.1 rather than clearly ahead.
Its Critical cybersecurity rating brings stricter safeguards to the general release.

GPT-6 Astra is a strong choice for teams that want AI to carry out work directly inside existing applications, especially where no API exists. For writing-heavy work, long document analysis, or cost-sensitive volume workloads, Claude Fable 5.1 and Gemini 3.8 Flash remain credible alternatives. Matching each workload to the right model, and routing lighter tasks to cheaper tiers, will deliver more value than choosing a single model on headline benchmark claims.

Frequently Asked Questions

GPT-6 Astra is the flagship AI model from OpenAI, released in September 2026. It is designed for demanding end-to-end work such as computer and browser use, software engineering, research, scientific analysis, and document creation.

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