GPT-6 Astra or GPT-5.6 Sol?
Evaluate Astra on difficult tasks that currently need retries or human repair. Keep Sol as a cost-conscious baseline for workflows that already meet your quality target. A larger token price alone cannot establish the cost of a successful task.
Testing demanding workflows and newer agent controls
Keeping a lower per-token baseline for established workflows
GPT-6 Astra
Complex coding, research and multi-step agent work with a configurable model
Official specification ↗GPT-5.6 Sol
Professional API workflows where token cost and reasoning controls matter
Official specification ↗Side-by-side comparison
| Category | GPT-6 Astra | GPT-5.6 Sol |
|---|---|---|
| Standard API input / 1M tokens | $10 | $4 |
| Standard API output / 1M tokens | $50 | $20 |
| Cached input / 1M tokens | $1 | $0.40 |
| Context / maximum output | 1,050,000 / 128,000 tokens | 1,050,000 / 128,000 tokens |
| Knowledge cutoff | April 30, 2026 | February 16, 2026 |
| Reasoning options | low, medium, high, xhigh, max | none, low, medium, high, xhigh, max |
| Billing caveat | Long-context, cache-write and tool fees can add cost | Long-context, cache-write and tool fees can add cost |
| Aivorix evaluation | No shared independent score recorded | Use the same tasks and harness before choosing |
| Company | OpenAI | OpenAI |
| Product category | Product · Reasoning Model | Product · Reasoning Model |
| Current pricing note | API / 1M tokens: $10 input, $1 cached input, $50 output; long-context/tool charges extra | API / 1M tokens: $4 input, $0.40 cached input, $20 output; long-context/tool charges extra |
| Best suited to | Complex coding, research and multi-step agent work with a configurable model | Professional API workflows where token cost and reasoning controls matter |
| Key capabilities | 1.05M-token context; up to 128K output; Text/image input and text output; Async tools and mid-turn steering; Reasoning effort from low to max | 1.05M-token context; up to 128K output; Text/image input and text output; Reasoning effort includes none; gpt-5.6 alias routes to Sol |
| Last verified | 2026-09-07 | 2026-09-07 |
| Official product source | https://developers.openai.com/api/docs/models/gpt-6-astra | https://developers.openai.com/api/docs/models/gpt-5.6-sol |
How we reached this verdict
We looked at the things that affect everyday use: what each product can do, how its plans are structured, where it fits into your existing workflow, and what the provider currently documents. Benchmark results are useful context, but they are not a universal winner score because test settings and tools vary.
Common questions
GPT-6 Astra or GPT-5.6 Sol: which should I choose?
Choose GPT-6 Astra for testing demanding workflows and newer agent controls. Choose GPT-5.6 Sol for keeping a lower per-token baseline for established workflows. Validate the decision with your own prompts and total task cost.
Is GPT-6 Astra cheaper than GPT-5.6 Sol?
Pricing units can differ. GPT-6 Astra: API / 1M tokens: $10 input, $1 cached input, $50 output; long-context/tool charges extra. GPT-5.6 Sol: API / 1M tokens: $4 input, $0.40 cached input, $20 output; long-context/tool charges extra. Check tool charges, plan limits, caching and long-context rules before comparing totals.
Which is better for coding and agent work?
Capability depends on the selected product surface, tools and harness. GPT-6 Astra is positioned for complex coding, research and multi-step agent work with a configurable model; GPT-5.6 Sol is positioned for professional api workflows where token cost and reasoning controls matter. Run the same repository task on both.
How do their context windows compare?
GPT-6 Astra lists Varies by included model and plan; GPT-5.6 Sol lists Varies by included model and plan. A larger limit does not by itself guarantee better retrieval or lower cost.
Official sources
Use these provider pages to confirm current features, pricing and availability.
AI tools change quickly. We checked this page on 2026-09-07. Before you subscribe, confirm the latest price, regional availability and usage limits on the provider website.