Lower standard token rates.
OpenAI positions Sol for complex coding and agentic workflows. It supports optional reasoning effort from none through max and a 1.05M context window.
$2 input · $10 output / MTokOpen Sol reference ↗MODEL COMPARISON / VERIFIED 2026-09-26
GPT-6 Sol
vs Claude Opus 5.5.
Two models released on September 22, 2026 and aimed at serious coding and agentic work. This comparison separates official specifications and pricing from vendor performance claims.
Long-running agentic work.
Anthropic positions Opus 5.5 for long-running agentic coding and knowledge work. Adaptive thinking is always on and its 1M context is billed at standard rates.
$4 input · $20 output / MTokOpen Opus 5.5 signals ↗OFFICIAL SPECIFICATIONS
Side-by-side facts.
| Model | Provider | Positioning | Context | Max output | Thinking | Input | Cache read | Cache write | Output |
|---|---|---|---|---|---|---|---|---|---|
| GPT-6 Solgpt-6-sol | OpenAI | Complex coding and agentic workflows | 1,050,000 | 128,000 | Optional; none through max | $2.00 | $0.20 | $2.50 | $10.00 |
| Claude Opus 5.5claude-opus-5-5 | Anthropic | Long-running agentic coding and knowledge work | 1,000,000 | 128,000 | Adaptive; always on | $4.00 | $0.20 | $5.00 / $8.00 | $20.00 |
Prices shown are standard per 1M tokens. Claude cache-write pricing is $5 for a 5-minute cache and $8 for a 1-hour cache. GPT-6 Sol cache write is $2.50 per 1M tokens at the listed standard short-context rate.
COST EXAMPLES
Same tokens, different billing.
Short-context request
GPT-6 Sol$0.3100K input + 10K output
Claude Opus 5.5$0.6100K input + 10K output
Monthly standard volume
GPT-6 Sol$3010M input + 1M output
Claude Opus 5.5$6010M input + 1M output
Single long-context request
GPT-6 Sol$2.75500K input + 50K output
Claude Opus 5.5$3500K input + 50K output
The 500K + 50K example applies OpenAI’s published long-context uplift to Sol and Anthropic’s standard Opus 5.5 rates. It excludes tool calls, regional processing and service-tier adjustments.
CONTEXT ECONOMICS
The gap narrows on very long prompts.
Sol’s standard uncached token prices are half of Opus 5.5. Above 272K input tokens, however, Sol’s full request moves to higher long-context rates while Anthropic says Opus 5.5 keeps standard pricing across its 1M context window.
CACHE READS
Both list $0.20 / MTok.
At standard rates, both vendors list $0.20 per million cached or cache-read input tokens. Their cache-write pricing and long-context billing differ, so agent cost depends on the shape of the workload rather than headline input price alone.
REASONING CONTROL
Optional vs always-on thinking.
GPT-6 Sol lets API users select reasoning effort from none to max. Claude Opus 5.5 uses adaptive thinking that cannot be disabled; Anthropic lists medium as its default effort.
BENCHMARK CAUTION
Keep vendor claims attributable.
Launch benchmark charts can use different harnesses, effort settings and comparison models. SXF keeps this page centered on directly comparable official specifications rather than declaring a benchmark winner from mismatched tests.
OFFICIAL SOURCES
OpenAI · GPT-6 Sol model card↗OpenAI · API pricing↗Anthropic · Claude Opus 5.5 model card↗Anthropic · Opus 5.5 announcement↗QUICK ANSWERS
How much cheaper is GPT-6 Sol than Claude Opus 5.5 at standard token rates?
At the official standard rates, GPT-6 Sol is priced at $2 input and $10 output per million tokens, while Claude Opus 5.5 is $4 input and $20 output. The uncached input and output rates are therefore half as high for Sol.
Do GPT-6 Sol and Claude Opus 5.5 have the same context window?
No. OpenAI lists a 1,050,000-token context window for GPT-6 Sol. Anthropic lists 1,000,000 tokens for Claude Opus 5.5. Both list a 128,000-token maximum output.
How do long-context prices differ?
OpenAI states that GPT-6 Sol requests above 272K input tokens use 2x input/cache rates and 1.5x output rates for the full request. Anthropic states that the 1M context window is standard and long-context requests are billed at standard pricing.
How does reasoning control differ?
GPT-6 Sol supports reasoning effort from none through max. Claude Opus 5.5 uses adaptive thinking that is always on, with medium as the default effort.
Which model is positioned for coding and agents?
Both vendors position these models for coding and agentic work. OpenAI describes Sol as built for complex coding and agentic workflows; Anthropic describes Opus 5.5 as built for long-running agentic coding and knowledge work.