GPT-6 Astra vs GPT-6.1 Sol

$1.54 / task
Wins 1 of 5 benchmarks
$0.21 / task
Wins 1 of 5 benchmarks
Arena Text · creative writing Arena Text · creative writing: Human pairwise preferences in the stated text vote pool
GPT-6 Astra · max1,450
GPT-6.1 Sol · max1,458
Harvey LAB-AA 1.1 Harvey LAB-AA 1.1: Legal agents work from case documents; every rubric criterion must pass and material hallucinations receive no credit
GPT-6 Astra · max8.6
GPT-6.1 Sol · max6.9
EQ-Bench Longform Creative Writing 1.11 Longform Creative Writing 1.11: Models plan, revise and write a story across eight turns, graded with a writing rubric
GPT-6 Astra82.8
GPT-6.1 Sol—
EQ-Bench Creative Writing v3 Creative Writing v3 · Elo: Judge-rated creative writing under the v3 prompt set and pairwise ranking
GPT-6 Astra2,173.3
GPT-6.1 Sol—
Lech Mazur Short-Story Lech Mazur Short-Story · comparison score: Judges compare stories written to ten required elements; the comparison score can be negative
GPT-6 Astra · high3.4
GPT-6.1 Sol—

Specs

SpecGPT-6 AstraGPT-6.1 Sol
Input, per 1M$10$2
Output, per 1M$50$10
Cost per task?$1.54$0.21
Speed, tok/s5945
Context1.05M1.05M
WeightsClosedClosed
ReleasedSep 2026Sep 2026
See images✓✓
Read PDFsPartialPartial
Hear audio——
Watch video——
Call tools✓✓
Force a tool callPartialPartial
Return strict JSON✓✓
Search the web✓✓
Run code✓✓
Use a computer✓✓

What breaks when you switch

GPT-6 Astra → GPT-6.1 Sol
Remove unsupported parameters›

With reasoning enabled, remove temperature, top_p and top_logprobs, plus Chat Completions logprobs or Responses message.output_text.logprobs includes.

Responses API for tool calling · Chat Completions›

Use Responses for tools; Chat Completions supports this model without tool calling.

No none or minimal reasoning›

The none and minimal reasoning efforts are unsupported; choose low, medium, high, xhigh or max.

More than 272K input tokens›

Prompts above 272K input tokens charge 2× input and cache rates and 1.5× output rates for the entire request.

Cache writes billed at 1.25x›

Cache writes cost 1.25× the uncached input token rate.

Ultrafast prices 6x Standard›

Ultrafast mode costs 6× Standard token prices.

GPT-6.1 Sol → GPT-6 Astra
Monitoring can return HTTP 403›

Misalignment monitoring can return HTTP 403 before streaming or errors after output; match misalignment_policy_violation and handle stream errors.

No none reasoning effort›

The none reasoning effort is unsupported on GPT-6 Astra and GPT-6.1 Sol; use low instead.

Remove unsupported sampling parameters›

When reasoning effort is not none, remove temperature, top_p and top_logprobs, plus Chat Completions logprobs or Responses output logprobs inclusion.