First frontier model family to clear a customer-by-customer US government review: limited preview June 26, full public release July 9, 2026. Pricing $5/$30 ($10/$45 above 272K context). Knowledge cutoff Feb 16, 2026.
Terminal-Bench 2.1 leader at 88.8% (91.9% ultra) — the top OpenAI agentic-coding result
94.6% GPQA Diamond and 90.4% BrowseComp — frontier science reasoning and agentic browsing
Artificial Analysis Coding Agent Index leader at 80 points, near Fable 5 intelligence at roughly one-third the cost
Weaknesses
Trails Claude Opus 5 badly on repository-level engineering (SWE-bench Pro 64.6% vs 79.2%)
Long-context surcharge ($10/$45 above 272K) and 2–3x ultra-mode costs stack up fast
Real-world use cases
What people actually use GPT-5.6 Sol for.
Tool-heavy terminal coding — 88.8% on Terminal-Bench 2.1 (91.9% in ultra mode, a state of the art)
Agentic web research at 90.4% BrowseComp with top-tier GPQA Diamond science reasoning (94.6%)
Long autonomous workflows using ultra mode's sub-agent orchestration
How GPT-5.6 Sol compares
The nearest models people weigh against it, and what actually separates them.
vs GPT-5 — Against GPT-5 (OpenAI), GPT-5.6 Sol costs about 6% more per token, takes 2.6x the context and answers slower. GPT-5 is the one to check first if the price difference matters more than the ceiling.
vs GPT-6 Astra — Against GPT-6 Astra (OpenAI), GPT-5.6 Sol runs about 80% cheaper per token. Take GPT-5.6 Sol unless you specifically need what GPT-6 Astra does better.
vs Claude Fable 5 — Against Claude Fable 5 (Anthropic), GPT-5.6 Sol runs about 80% cheaper per token and takes 1.1x the context. Take GPT-5.6 Sol unless you specifically need what Claude Fable 5 does better.
Price History
GPT-5.6 Sol pricing over time
↓20% since Aug 7
26 data points · tracked daily since Aug 7, 2026
Ready to try it?
Start using GPT-5.6 Sol
Frontier agentic coding, deep research, and hardest reasoning tasks. Start free — no card required.
GPT-5 is OpenAI's flagship multimodal model, superseding GPT-4o with significantly improved reasoning, instruction-following, and knowledge breadth. It handles text, images, and complex multi-step tasks with state-of-the-art performance across most benchmarks.
Verdict
OpenAI's best general-purpose model — a strong flagship pick that punches above its price on input costs while delivering top-tier reasoning and multimodal capability.
Quality score
87%
Pricing
$1.25/1M in
$10.00/1M out
Speed
Balanced
3/5 speed
Context
400k tokens
Pricing is asymmetric: cheap on input ($1.25/1M) but expensive on output ($10/1M), so it favors read-heavy or summarization tasks over verbose generation. The 400K context window is one of the largest available at this price tier. Supersedes GPT-4o, which remains available at lower cost for lighter workloads.
FlagshipMultimodalLong ContextOpenAIReasoning
Best for
High-stakes professional tasks requiring deep reasoning, precise instruction-following, and reliable multimodal understanding.
OpenAI's September 3, 2026 frontier release — the first GPT-6 model and OpenAI's answer to Claude Fable 5.1 two days earlier. State of the art on computer use (OSWorld 2.0 72.6% in ~47% less time than GPT-5.6 Sol), agentic coding (Terminal-Bench 4.0 57.9%), and frontier math (FrontierMath Tier 4 97.6%). $10/$50 per 1M tokens, 1.05M context, 128K output, knowledge cutoff April 30, 2026.
Verdict
OpenAI's frontier answer to Fable 5.1 — computer-use and agentic-coding leader at $10/$50.
Quality score
99%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
2/5 speed
Context
1.1M tokens
Released September 3, 2026. API ID gpt-6-astra; rolling out over the coming days to ChatGPT Plus, Pro, Business and Enterprise (usage inside existing allowances; GPT-6 Astra Pro for Pro/Business/Enterprise; Enterprise off by default), the OpenAI API, Microsoft Azure and Amazon Bedrock. Standard API pricing $10/$50 per 1M tokens; Fast mode is up to 2x speed at 2x price; cache reads and writes have separate rates. Model docs list 1,050,000 context, 128,000 max output, knowledge cutoff April 30, 2026, reasoning efforts up to 'max'. Published launch numbers (Astra / GPT-5.6 Sol / Fable 5.1 / Opus 5): OSWorld 2.0 72.6 / 65.7 / — / 70.2; Terminal-Bench 4.0 57.9 / 37.3 / 55.8 / 52.3; Terminal-Bench Science 0.1 64.6 / 22.4 / 52.6 / 30.0; FrontierMath Tier 4 v2 97.6 / 83.0 / 87.8 / 73.2; GPQA Diamond 96.0 / 94.6 / 93.7 / 93.7; Humanity's Last Exam w/ tools 57.2 / — / 65.0 / 63.6; AutomationBench 41.4 / 18.1 / 31.4 / 26.9; DeepSWE v1.1 74.1 / 72.7 / 67.4 / 73.7; ARC-AGI-2 95.0 / 92.5 / 90.0 / 90.4; ARC-AGI-3 99.9 (OpenAI responses-API harness; ARC Prize's stateless runs score far lower) / 7.8 / — / 30.2; ExploitBench 100.0 / 78.5 / — / 70; SRE-Bench 88.0 / 55.9; Artificial Analysis Intelligence Index v4.1.1 61.2 / 60.9 / 65.7 / 63.1. Meets the Critical threshold for cybersecurity under OpenAI's Preparedness Framework; advanced cyber workflows gated behind OpenAI Daybreak. All figures from OpenAI's launch post and model docs, verified September 4, 2026.
Computer use leaderFrontierAgenticReasoningLong contextPremiumNew
Best for
Computer and browser use, long-horizon agentic coding, and frontier math and science work
Anthropic's new Mythos-class flagship and the most capable coding model anyone can use — 80.3% SWE-Bench Pro, an 11-point jump over Opus 4.8. 1M context, 128K output, native parallel subagents. Released June 9, 2026.
Verdict
New global #1 — 80.3% SWE-Bench Pro, the most capable model generally available.
Quality score
98%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
2/5 speed
Context
1M tokens
Launched June 9, 2026 as the public, Mythos-class release. Available on the Claude API, Microsoft Foundry, and Google Vertex AI. Free for all users until June 22, 2026. Same underlying model as Claude Mythos 5, with safeguards that block specific high-risk cyber responses.
Coding leaderSWE-Bench Pro #1Mythos-classParallel subagentsAgenticLong contextPremiumNew
Best for
The hardest coding tasks, autonomous multi-step agents, and frontier-grade reasoning
GPT-5.6 Sol costs $2 per million input tokens and $10 per million output tokens on the API, with cached input at $0.2 per million. A month of 10M input and 2M output tokens runs about $40.00 at list price, before any batch or caching discounts.
What is the context window of GPT-5.6 Sol?
GPT-5.6 Sol has a 1.1M tokens context window, with up to 128k tokens of output per response. That is the total of prompt plus response the model can hold in one request.
What is the knowledge cutoff of GPT-5.6 Sol?
GPT-5.6 Sol's training data runs through February 16, 2026, and the model was released on July 9, 2026. For anything after that date it needs web search or documents in the prompt.
What is GPT-5.6 Sol best for?
GPT-5.6 Sol is best for frontier agentic coding, deep research, and hardest reasoning tasks. It is a strong fit when that workflow matters more than the tradeoffs around premium pricing and deliberate speed.
When should I avoid GPT-5.6 Sol?
Repo-level coding is the main job — Opus 5 leads SWE-bench Pro by ~15 points — or you're cost-sensitive (Terra is 60% cheaper at 1–4 points off).
What is a cheaper alternative to GPT-5.6 Sol?
GPT-5 (OpenAI) at $1.25/1M/1M input against GPT-5.6 Sol's $2.00/1M/1M — roughly 6% less per token all in. OpenAI's best general-purpose model — a strong flagship pick that punches above its price on input costs while delivering top-tier reasoning and multimodal capability. Compare it first if GPT-5.6 Sol's pricing is the thing stopping you.
What is a faster alternative to GPT-5.6 Sol?
GPT-6 Astra — deliberate against GPT-5.6 Sol's deliberate, with 1.1M tokens of context. Worth the swap when response time is what your users notice rather than the last few points of reasoning depth.
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