Claude Opus 4.7, GPT-5.4, Kimi K2.6, Gemini 3.1 Pro, DeepSeek V3.2: benchmarks, context windows, agent reliability, and cost — so you reach for the right one.
If you are asking which AI model is best for coding in 2026, or cheapest for bulk automation, or which handles long documents without truncating them, this post has those answers. Five frontier models shipped in early 2026: Claude Opus 4.7, GPT-5.4, Kimi K2.6, Gemini 3.1 Pro, and DeepSeek V3.2. All of them are capable. None of them is best at everything. Pick the wrong one for the job and you pay more, get worse output, or both.
This post covers four categories that actually matter for builders: coding, long documents, multi-step agent tasks, and cost. Each model gets a fair look. The goal is a fast answer to "which model do I reach for right now?"
Five different companies. Five different bets on what matters most.
Model
Maker
Input / Output (per 1M tokens)
Context Window
Claude Opus 4.7
Anthropic
$5 / $25
1M tokens
GPT-5.4
OpenAI
$2.50 / $15
256K tokens
Kimi K2.6
Moonshot
$3 / $15
512K tokens
Gemini 3.1 Pro
Google
$2 / $12
2M tokens
DeepSeek V3.2
DeepSeek
$1 / $4
128K tokens
The price spread is real but not always in the direction you'd expect. DeepSeek V3.2 costs $1 per million input tokens. GPT-5.4 costs $2.50 for the same amount. Claude Opus 4.7 at $5 input is actually the most expensive on input, twice GPT-5.4's price.
Context windows vary by 16x from smallest to largest. DeepSeek's 128K window handles a medium codebase. Gemini's 2M window fits an entire monorepo without truncation. That gap is not a footnote. For the right workloads, it is the whole decision.
Each model reflects a different priority. Anthropic built Opus 4.7 for accuracy and long-running coherence. OpenAI built GPT-5.4 for speed and retrieval quality. Moonshot built Kimi K2.6 to be affordable with strong multilingual support. Google built Gemini 3.1 Pro around a huge context window as the primary differentiator. DeepSeek built V3.2 to be the cheapest capable model in the field, full stop.
None of those bets is wrong. They are just different, and different tasks call for different bets.
The short answer: yes, for messy real-world coding. For clean, well-specified tasks, they are nearly even.
The standard way to evaluate coding models is SWE-Bench, a set of real GitHub issues where the model has to write a fix that passes the test suite. It is a good benchmark. It also skews toward clean, well-specified problems where the goal is clear.
CursorBench runs a different kind of evaluation. It uses real prompts from Cursor users. Messy, underspecified, half-broken codebases. The kind of problems actual developers bring to an AI every day.
Model
Score
Benchmark
Claude Opus 4.7
70%
CursorBench
GPT-5.4
68%
SWE-Bench
Gemini 3.1 Pro
63%
SWE-Bench
Kimi K2.6
58%
HumanEval
DeepSeek V3.2
52%
HumanEval
Opus 4.7 leads CursorBench at 70%. GPT-5.4 comes close at 68% on SWE-Bench. When the benchmarks are directly comparable, the two models are nearly even on clean problems. When the problems get messy and underspecified, the gap widens in Opus 4.7's favor.
What makes Opus 4.7 different on hard coding tasks is self-correction. Most models generate code, declare it done, and move to the next step. Opus 4.7 reviews what it just wrote, spots the type error or logic gap, and fixes it in the same pass. On hard problems that take multiple reasoning steps, that compounds. One fewer debugging loop per session adds up across a full week of engineering work.
GPT-5.4 is fast and strong on well-defined tasks. Give it a clear spec and it executes reliably. Give it a vague or half-broken codebase and it drifts more than Opus 4.7 does. For daily coding on a clean, well-tested repo, the difference is small. For debugging sessions in a legacy system with no tests and inconsistent patterns, the gap is real.
Gemini 3.1 Pro at 63% is a solid coding model, especially when the task requires pulling context from a large codebase. The 2M window means it can read the whole thing. Where it falls behind is on the hardest reasoning problems, the kind where you need the model to hold a complex chain of logic across many steps without losing the thread.
Kimi K2.6 and DeepSeek V3.2 score lower on coding benchmarks, but benchmarks do not capture everything. DeepSeek V3.2 in particular is surprisingly capable on standard implementation tasks for its price. If the prompt is clear and the problem is not ambiguous, it delivers. It just does not belong on the hard stuff, and it will let you know when it is out of its depth.
Context window size and document reasoning quality are two different things. A huge window is useless if the model loses track of what it read. Strong reasoning over text is limited if the document does not fit in the first place.
Both dimensions matter. They just matter for different tasks.
Model
Context Window
Long-Doc Strength
Gemini 3.1 Pro
2M tokens
Biggest window. Entire codebases fit without truncation.
Claude Opus 4.7
1M tokens
21% fewer doc errors. Best reasoning over long text.
Kimi K2.6
512K tokens
Strong on Chinese-language documents.
GPT-5.4
256K tokens
Good retrieval. Shorter window limits large source sets.
DeepSeek V3.2
128K tokens
Works for medium-length documents. Hits limits on large ones.
The AI model with the longest context window is Gemini 3.1 Pro at 2M tokens. That is genuinely useful for real workloads: a large monorepo, a full set of legal contracts, a year of financial filings from a public company. Nothing gets truncated. If the task is "read everything and extract what matters," Gemini is the right tool because it is the only model in this group that can hold all of it at once.
Opus 4.7's edge is accuracy over what it reads. On dense source material where precise reasoning matters, it produces 21% fewer errors than its predecessor. That gap shows up most clearly in legal and financial work where a wrong clause or misread number has consequences. You can fit more raw text into Gemini, but Opus 4.7 does more with the text it reads.
A practical combination for large, high-stakes documents: use Gemini 3.1 Pro for the initial pass across the full document. It can read everything without cutting anything off. Then use Opus 4.7 for the sections that require careful reasoning. You get the full picture from Gemini and the accuracy from Opus 4.7 on the parts that matter.
Kimi K2.6 is strong on Chinese-language documents. That is a specific but real use case. Moonshot has invested heavily in multilingual performance, and it shows. If your documents are in Chinese, Kimi K2.6 is worth testing before defaulting to any of the English-first models in this group.
GPT-5.4 retrieves well within its 256K window. The constraint is the window itself. A single large contract or a moderate codebase fits. A set of five large contracts or a complex multi-module repo does not. For teams working with smaller documents or running frequent shorter queries, 256K is fine. For teams doing document-heavy work across large source sets, it is a binding constraint.
DeepSeek V3.2's 128K window works for medium documents. A typical engineering spec, a legal contract under 60 pages, a financial report for one quarter. Anything larger and you are chunking it, which adds complexity and risks losing cross-section context. For bulk document tasks where the documents are short and well-structured, DeepSeek is still cost-effective. For complex long-form analysis, the window is genuinely limiting.
Agent tasks are where the real separation between models shows up. A model that is great at one-shot prompts can fall apart when it has to run for 20 steps, use tools, and keep track of what it already did.
The failure mode looks the same across models: the agent starts losing coherence around step 10 to 15. It forgets what it already checked. It tries an approach it already tried. It produces a "done" message when the task is half-finished. That pattern is what makes autonomous work unreliable.
Model
Agent Quality
Speed
Cost
Claude Opus 4.7
Best
Medium
$$$
GPT-5.4
Strong
Fast
$$$
DeepSeek V3.2
Good
Fast
$
Gemini 3.1 Pro
Good
Medium
$$
Kimi K2.6
Decent
Fast
$$
Opus 4.7 stays coherent across hours of work. It has the lowest tool error rate of the group. On agent chains that involve reading files, calling APIs, writing code, and verifying the result, it does not lose the thread. Its self-correction behavior, the same property that helps it in coding, applies to agent runs too. When a tool call returns an unexpected result, Opus 4.7 adjusts rather than proceeding on a false assumption.
The practical payoff is that you can set Opus 4.7 on a multi-hour task, walk away, and come back to actual results. Not "the agent got 60% through and then started repeating itself." Real, verifiable completion.
GPT-5.4 is strong on short chains. For a 3-to-5-step task where each step is well-defined and the model can verify its own output quickly, it is fast and reliable. It is also the fastest model in this group, which matters for interactive workflows where you are watching the agent work and course-correcting in real time. On longer chains where state has to carry across many steps, reliability drops compared to Opus 4.7. Not broken. Just less consistent at the long end.
DeepSeek V3.2 is the right call for lightweight agent work at volume. Bulk tagging tasks, simple classification pipelines, templated generation across large datasets, structured data extraction from well-formatted documents. It costs a quarter of what Opus 4.7 costs. For tasks that do not need deep reasoning, the savings add up fast. Running 10 million tokens of bulk processing through DeepSeek instead of Opus saves about $61 for that batch alone.
Gemini 3.1 Pro handles agent tasks that require enormous context as input. Its tool use is reliable. When the task is "read this entire codebase and then do something with it," the 2M window means it does not have to summarize or truncate before acting. For tasks that are context-heavy but not deeply reasoning-heavy, Gemini is a reasonable choice at a mid-range price.
Kimi K2.6 handles simple agent tasks. It starts to struggle when the flow requires multi-hop reasoning across many tool calls or when the task requires holding a complex state across steps. Keep it on simpler chains, especially in Chinese-language contexts where it performs above the benchmark numbers.
Headline prices only tell half the story. The actual cost depends on what you are running.
Daily coding sessions (roughly 200K tokens each):
Model
Cost per Session
DeepSeek V3.2
$0.26
Gemini 3.1 Pro
$0.75
Kimi K2.6
$0.90
Opus 4.7
$1.75
GPT-5.4
$1.60
For coding sessions, DeepSeek is 6x cheaper than Opus 4.7. GPT-5.4 is actually cheaper than Opus 4.7 per session at these prices, but that advantage disappears on hard tasks where Opus 4.7's self-correction saves debugging time.
Long document analysis (500K token job):
Model
Cost
Notes
DeepSeek V3.2
$0.70
128K limit requires chunking above that
Gemini 3.1 Pro
$1.90
Fits comfortably within 2M window
Kimi K2.6
$2.25
Fits within 512K window
Opus 4.7
$3.75
Fits within 1M window
GPT-5.4
$3.25
256K limit requires chunking
For document work, Gemini 3.1 Pro has the biggest window at the second-lowest price. GPT-5.4 costs less than Opus 4.7 but still requires chunking for anything over 256K tokens.
High-volume automation (10M tokens per month, bulk tasks):
Model
Monthly Cost
DeepSeek V3.2
$14
Gemini 3.1 Pro
$35
Kimi K2.6
$39
Opus 4.7
$75
GPT-5.4
$78
At bulk volumes, DeepSeek V3.2 is not just cheaper. It is in a different price category entirely. $14 versus $130 for the same token volume is not a small optimization. It is a fundamentally different operating cost.
The right model depends on what you are actually doing. Four scenarios with clear answers:
Hard coding, debugging, code review. Use Claude Opus 4.7. It catches its own mistakes. It clears the hard class of problems that trip up other models. At $5/$25, it is more expensive than GPT-5.4 per token, but it saves the debugging rounds that cost more in time than in API fees. If you are asking which AI model should I use for coding in 2026, Opus 4.7 is the answer for anything non-trivial.
Giant documents. Legal, finance, contracts, large codebases. Use Gemini 3.1 Pro. The 2M context window fits everything without truncation. Nothing gets cut off. For situations where you need to reason carefully over the full document, pair Gemini with Opus 4.7: Gemini reads the whole source, Opus handles the analysis sections that need precision.
Bulk automation with many cheap calls. Use DeepSeek V3.2. At $1/$4, it is the cheapest frontier AI model available right now, costing a quarter of what Opus 4.7 costs and delivering accurate results on well-defined tasks. Tagging, classification, templated generation, lightweight summarization. The savings on 10 million tokens a month are not marginal.
Long agent runs, hours of autonomous work. Use Claude Opus 4.7. It does not stop early. It holds the lowest tool error rate of the group. For work where you want to walk away and come back to a finished result, Opus 4.7 is the most consistent option here.
The default pair for most builders. Opus 4.7 handles the tasks where quality decides the outcome. DeepSeek V3.2 handles the tasks where volume and cost decide the outcome. Those two together cover 90% of what most builders actually need.
The Claude vs GPT comparison question comes up constantly. Here is the direct breakdown.
GPT-5.4 wins on web research. Its BrowseComp score is 89.3% versus Claude's 79.3%. If your workflow involves heavy internet retrieval, GPT-5.4 is meaningfully better at pulling accurate answers from the web. It is also the faster model for short, interactive tasks.
Claude Opus 4.7 wins on coding, agents, and finance/legal accuracy. The 10 point gap on BrowseComp does not matter if you are not doing live web research. For codebases, autonomous agents, and document analysis where precision drives outcomes, Opus 4.7 is more reliable.
GPT-5.4 costs $2.50/$15 per million tokens. Claude Opus 4.7 costs $5/$25. GPT-5.4 is actually cheaper on both input and output. The case for Claude is not price: it is quality on hard tasks. Self-correction, agent coherence, and finance/legal accuracy are where the extra cost earns back.
The conversational feel of GPT-5.4 is a real thing, not just preference. It is snappier and feels more natural for back-and-forth chat. That matters for some workflows, particularly customer-facing applications. For builder workflows where output quality and reliability matter more than conversational tone, Claude Opus 4.7 is the better default.
The marketing around AI models wants you to believe one model is best at everything. None of these five is.
Gemini 3.1 Pro has the biggest context window and the most competitive pricing of the non-DeepSeek models. Opus 4.7 has the best reasoning and the best agent coherence. DeepSeek V3.2 has the best price by a wide margin. GPT-5.4 has strong retrieval speed and web research quality. Kimi K2.6 has a specific edge on Chinese-language work at a competitive price.
The question is never "which model is best." It is "which model is right for this task." Get that question right, and you spend less, finish faster, and fix fewer mistakes on the other side.
It depends on the task. For coding, agents, and finance/legal document work, Claude Opus 4.7 wins. It scores 70% on CursorBench versus GPT-5.4's 68% on SWE-Bench and holds the lowest tool error rate for multi-step agents. GPT-5.4 is actually cheaper ($2.50/$15 per million tokens vs Claude's $5/$25) and wins on web research (BrowseComp 89.3% vs 79.3%). The case for Claude is quality on hard tasks, not price.
DeepSeek V3.2 Speciale is the cheapest frontier AI model available right now, at $1 per million input tokens and $4 per million output tokens. That is roughly 59x cheaper on output than Claude Opus 4.7 ($25 output) and about 7.5x cheaper than Gemini 3.1 Pro ($12 output). DeepSeek V3.2 carries an MIT license, making it usable commercially without restrictions. The trade-off: 128K context window, no tool calling in the Speciale variant, and it is not suited for the hardest reasoning tasks.
Claude Opus 4.7 is the best AI model for coding in 2026, scoring 70% on CursorBench with real developer prompts. Its key edge is self-correction: it reviews its own code output in the same pass, catches type errors and logic gaps before you see them, and outperforms other models on messy, underspecified codebases. GPT-5.4 is close at 68% on clean SWE-Bench tasks. For high-volume, well-defined coding at low cost, DeepSeek V3.2 punches above its weight at $0.26 per session.
Gemini 3.1 Pro has the longest context window of any model in this comparison, at 2 million tokens. That is 2x Claude Opus 4.7's 1M window, nearly 4x Kimi K2.6's 512K, and 15x DeepSeek V3.2's 128K. The 2M window means an entire large monorepo, a year of legal contracts, or a full financial filing history fits in a single context without truncation or chunking. Gemini 3.1 Pro is in preview status as of this writing.
Yes, for tasks where quality drives outcomes. At $5/$25 per million tokens, Opus 4.7 is more expensive than GPT-5.4 ($2.50/$15) but delivers better results on coding and agents. It is more expensive than Gemini 3.1 Pro ($2/$12) and significantly more expensive than DeepSeek ($1/$4). The value calculation: use Opus 4.7 for hard coding, debugging, multi-hour agent runs, and high-stakes document analysis. Route bulk processing and simple tasks to DeepSeek. That split captures the quality where it matters without overpaying.
DeepSeek V3.2 is best at high-volume, well-defined tasks where cost is the primary constraint. It scores 96% on AIME math benchmarks and IMO gold-level competition problems, making it exceptional at mathematical reasoning. It is the top open-source model for competitive coding. For bulk automation: tagging, classification, structured extraction, templated generation at scale, it costs $14 per 10 million tokens versus $130 for GPT-5.4. The Speciale variant carries an MIT license. Key limitations: 128K context window and no tool calling in the Speciale variant.
No. Gemini 3.1 Pro is not available on a free tier. Only Flash-tier Gemini models are available for free. Gemini 3.1 Pro costs $2 per million input tokens and $12 per million output tokens, and it is currently in preview status. If you need a free tier for experimentation, use one of Google's Flash models instead.
It depends on whether your priority is fitting the document or reasoning accurately over it. For the longest raw context (fitting everything without truncation), Gemini 3.1 Pro at 2M tokens is the best AI model for long documents. For accurate reasoning over long, dense text (legal contracts, financial filings, technical specs), Claude Opus 4.7 produces 21% fewer document errors and is the better choice when precision matters. The optimal pattern for high-stakes long documents: Gemini for the full-document read, Claude Opus 4.7 for the sections that need careful analysis.