Pick Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously or multi-step coding, debugging, and tool use. Pick GPT-6 Sol for openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment or openai says it makes about half as many mistakes as gpt-5.6 sol.
Claude Sonnet 5 (Anthropic) and GPT-6 Sol (OpenAI) are two of the models people most often weigh against each other in 2026. Claude Sonnet 5 is anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. GPT-6 Sol is openAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Their biggest split is context window, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Context window: 1M vs 1.05M tokens — within a few percent of each other, so treat this as a tie and test on your own long inputs, since usable recall varies by model.
Recency: GPT-6 Sol is the newer model by about 3 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Sonnet 5
GPT-6 Sol
Provider
Anthropic (US)
OpenAI (US)
Released
June 30, 2026
September 22, 2026
Context window
1M (~1,500 pages)
1.05M tokens (~1,575 pages)
Price (in/out)
$2/$10 per 1M tokens
$2/$10 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Agentic workflows that plan, use tools, and run autonomously: Claude Sonnet 5 — Claude Sonnet 5 lists agentic workflows that plan, use tools, and run autonomously among its strengths; GPT-6 Sol does not.
Multi-step coding, debugging, and tool use: Claude Sonnet 5 — Claude Sonnet 5 lists multi-step coding, debugging, and tool use among its strengths; GPT-6 Sol does not.
Everyday professional and knowledge work: Claude Sonnet 5 — Claude Sonnet 5 lists everyday professional and knowledge work among its strengths; GPT-6 Sol does not.
OpenAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment: GPT-6 Sol — OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens — and it is the newer of the two.
OpenAI says it makes about half as many mistakes as GPT-5.6 Sol: GPT-6 Sol — GPT-6 Sol lists openAI says it makes about half as many mistakes as GPT-5.6 Sol among its strengths; Claude Sonnet 5 does not.
Priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30): GPT-6 Sol — GPT-6 Sol lists priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30) among its strengths; Claude Sonnet 5 does not.
Which should you pick?
Someone analysing very long documents or codebases: GPT-6 Sol — Larger 1.05M tokens window fits more in one prompt.
Anyone whose priority is agentic workflows that plan, use tools, and run autonomously: Claude Sonnet 5 — It is specifically built for that.
Anyone whose priority is openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment: GPT-6 Sol — That is its strongest area.
Claude Sonnet 5: where it fits
Anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. Released June 30, 2026 by Anthropic, it is built for agentic workflows that plan, use tools, and run autonomously, multi-step coding, debugging, and tool use, everyday professional and knowledge work, and long-document analysis and reasoning.
Its trade-offs are real: lower peak accuracy than Opus 4.8 on the hardest tasks, and an updated tokenizer that can use 1.0-1.35x more tokens for the same text. At $2 in / $10 out per million tokens, it sits in the mid price band.
GPT-6 Sol: where it fits
OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Released September 22, 2026 by OpenAI, it is built for openAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment, openAI says it makes about half as many mistakes as GPT-5.6 Sol, priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30), and 1.05M-token context window, input capped at 922K.
Its trade-offs: more reasoning capability than sibling GPT-6 Luna, but still positioned below flagship GPT-6 Astra, and cache-read pricing ($0.20/MTok) still costlier than Luna's ($0.01/MTok) for high-cache workloads. At $2 in / $10 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Sonnet 5 and GPT-6 Sol overlap enough that the right pick depends on your specific job. GPT-6 Sol holds the larger context; and each leads in its own area — Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously, GPT-6 Sol for openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment. Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Claude Sonnet 5 or GPT-6 Sol better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 5 leans toward agentic workflows that plan, use tools, and run autonomously while GPT-6 Sol leans toward openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 5 or GPT-6 Sol?
They are priced almost identically, so cost will not decide between them.
Which has the bigger context window?
Effectively neither — 1M vs 1.05M tokens is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Claude Sonnet 5 and GPT-6 Sol together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 5, GPT-6 Sol and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Sonnet 5 or GPT-6 Sol?
GPT-6 Sol — released September 22, 2026, about 3 months after Claude Sonnet 5.
Claude Sonnet 5 vs GPT-6 Sol
Anthropic · US | OpenAI · US · Updated June 2026
Quick verdict
Pick Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously or multi-step coding, debugging, and tool use. Pick GPT-6 Sol for openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment or openai says it makes about half as many mistakes as gpt-5.6 sol.
Claude Sonnet 5 (Anthropic) and GPT-6 Sol (OpenAI) are two of the models people most often weigh against each other in 2026. Claude Sonnet 5 is anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. GPT-6 Sol is openAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Their biggest split is context window, and the breakdown below shows exactly how that plays out for your workload.
Key differences at a glance
▸Context window: 1M vs 1.05M tokens — within a few percent of each other, so treat this as a tie and test on your own long inputs, since usable recall varies by model.
▸Recency: GPT-6 Sol is the newer model by about 3 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Sonnet 5
GPT-6 Sol
Provider
Anthropic (US)
OpenAI (US)
Released
June 30, 2026
September 22, 2026
Context window
1M (~1,500 pages)
1.05M tokens (~1,575 pages)
Price (in/out)
$2/$10 per 1M tokens
$2/$10 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Agentic workflows that plan, use tools, and run autonomously
Claude Sonnet 5
Claude Sonnet 5 lists agentic workflows that plan, use tools, and run autonomously among its strengths; GPT-6 Sol does not.
Multi-step coding, debugging, and tool use
Claude Sonnet 5
Claude Sonnet 5 lists multi-step coding, debugging, and tool use among its strengths; GPT-6 Sol does not.
Everyday professional and knowledge work
Claude Sonnet 5
Claude Sonnet 5 lists everyday professional and knowledge work among its strengths; GPT-6 Sol does not.
OpenAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment
GPT-6 Sol
OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens — and it is the newer of the two.
OpenAI says it makes about half as many mistakes as GPT-5.6 Sol
GPT-6 Sol
GPT-6 Sol lists openAI says it makes about half as many mistakes as GPT-5.6 Sol among its strengths; Claude Sonnet 5 does not.
Priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30)
GPT-6 Sol
GPT-6 Sol lists priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30) among its strengths; Claude Sonnet 5 does not.
Which should you pick?
Someone analysing very long documents or codebases
→ GPT-6 Sol
Larger 1.05M tokens window fits more in one prompt.
Anyone whose priority is agentic workflows that plan, use tools, and run autonomously
→ Claude Sonnet 5
It is specifically built for that.
Anyone whose priority is openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment
→ GPT-6 Sol
That is its strongest area.
Claude Sonnet 5: where it fits
Anthropic's most agentic Sonnet, with near-Opus-4.8 performance at Sonnet prices; the default model on Free and Pro. Released June 30, 2026 by Anthropic, it is built for agentic workflows that plan, use tools, and run autonomously, multi-step coding, debugging, and tool use, everyday professional and knowledge work, and long-document analysis and reasoning.
Its trade-offs are real: lower peak accuracy than Opus 4.8 on the hardest tasks, and an updated tokenizer that can use 1.0-1.35x more tokens for the same text. At $2 in / $10 out per million tokens, it sits in the mid price band.
GPT-6 Sol: where it fits
OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Released September 22, 2026 by OpenAI, it is built for openAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment, openAI says it makes about half as many mistakes as GPT-5.6 Sol, priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30), and 1.05M-token context window, input capped at 922K.
Its trade-offs: more reasoning capability than sibling GPT-6 Luna, but still positioned below flagship GPT-6 Astra, and cache-read pricing ($0.20/MTok) still costlier than Luna's ($0.01/MTok) for high-cache workloads. At $2 in / $10 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Sonnet 5 and GPT-6 Sol overlap enough that the right pick depends on your specific job. GPT-6 Sol holds the larger context; and each leads in its own area — Claude Sonnet 5 for agentic workflows that plan, use tools, and run autonomously, GPT-6 Sol for openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Sonnet 5 and GPT-6 Sol without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
Is Claude Sonnet 5 or GPT-6 Sol better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 5 leans toward agentic workflows that plan, use tools, and run autonomously while GPT-6 Sol leans toward openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 5 or GPT-6 Sol?
They are priced almost identically, so cost will not decide between them.
Which has the bigger context window?
Effectively neither — 1M vs 1.05M tokens is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Claude Sonnet 5 and GPT-6 Sol together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 5, GPT-6 Sol and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Sonnet 5 or GPT-6 Sol?
GPT-6 Sol — released September 22, 2026, about 3 months after Claude Sonnet 5.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.