Claude Sonnet 4.5 vs MAI-Thinking-1

Anthropic · US  |  Microsoft · US · Updated June 2026

Quick verdict

Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick MAI-Thinking-1 for very strong math reasoning (aime 2025 97%, aime 2026 94.5%) or microsoft's first in-house flagship reasoner, trained without openai distillation. On a tight budget at scale, MAI-Thinking-1 is the value pick.

Claude Sonnet 4.5 (Anthropic) and MAI-Thinking-1 (Microsoft) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. MAI-Thinking-1 is microsoft's first fully in-house flagship reasoning model — a Claude-class reasoner built independently to cut its OpenAI dependence. They diverge most on price and context window — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecClaude Sonnet 4.5MAI-Thinking-1
ProviderAnthropic (US) Microsoft (US)
ReleasedSeptember 29, 2025 June 2, 2026
Context window200K (~300 pages) 256K (~384 pages)
Price (in/out)$3/$15 per 1M tokens Not published
Open weight?No — API only No — API only
Modalitiestext, image, code text, code
SWE-Bench Verified77.2% Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch

Claude Sonnet 4.5

MAI-Thinking-1 is comparatively weak here — benchmarks are largely self-reported

Computer use and GUI automation (61.4% OSWorld at launch)

Claude Sonnet 4.5

Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; MAI-Thinking-1 does not.

Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks

Claude Sonnet 4.5

Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; MAI-Thinking-1 does not.

Very strong math reasoning (AIME 2025 97%, AIME 2026 94.5%)

MAI-Thinking-1

Microsoft's first fully in-house flagship reasoning model — a Claude-class reasoner built independently to cut its OpenAI dependence — and it carries the larger 256K context.

Microsoft's first in-house flagship reasoner, trained without OpenAI distillation

MAI-Thinking-1

Microsoft's first fully in-house flagship reasoning model — a Claude-class reasoner built independently to cut its OpenAI dependence — and it is the newer of the two.

Efficient reasoning at low token cost for its class

MAI-Thinking-1

Its 256K window holds about 1.3× more than Claude Sonnet 4.5's 200K in a single prompt.

Lowest cost at scale

MAI-Thinking-1

Its weights are open, so at volume you pay for your own hardware instead of Claude Sonnet 4.5's $3/$15 per 1M tokens.

Largest single-prompt input

MAI-Thinking-1

Its 256K window is about 1.3× larger than Claude Sonnet 4.5's 200K, fitting roughly 384 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

MAI-Thinking-1

At Not published it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

MAI-Thinking-1

Larger 256K window fits more in one prompt.

Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch

Claude Sonnet 4.5

It is specifically built for that.

Anyone whose priority is very strong math reasoning (aime 2025 97%, aime 2026 94.5%)

MAI-Thinking-1

That is its strongest area.

Claude Sonnet 4.5: where it fits

September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.

Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.

MAI-Thinking-1: where it fits

Microsoft's first fully in-house flagship reasoning model — a Claude-class reasoner built independently to cut its OpenAI dependence. Released June 2, 2026 by Microsoft, it is built for very strong math reasoning (AIME 2025 97%, AIME 2026 94.5%), microsoft's first in-house flagship reasoner, trained without OpenAI distillation, efficient reasoning at low token cost for its class, and competitive with Claude Opus 4.6 on SWE-Bench Pro (vendor-reported).

Its trade-offs: closed and in private preview — no open weights, no published pricing, thin availability, and benchmarks are largely self-reported.

The bottom line for this matchup

Claude Sonnet 4.5 and MAI-Thinking-1 overlap enough that the right pick depends on your specific job. MAI-Thinking-1 costs less per token; MAI-Thinking-1 holds the larger context; and each leads in its own area — Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, MAI-Thinking-1 for very strong math reasoning (aime 2025 97%, aime 2026 94.5%). Rather than crowning one, run the same hard task through both once and let the results decide.

Want both Claude Sonnet 4.5 and MAI-Thinking-1 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.

See pricing

Frequently asked questions

Is Claude Sonnet 4.5 or MAI-Thinking-1 better for coding?

Public SWE-Bench figures are not available for MAI-Thinking-1, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch while MAI-Thinking-1 leans toward very strong math reasoning (aime 2025 97%, aime 2026 94.5%), and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Claude Sonnet 4.5 or MAI-Thinking-1?

MAI-Thinking-1 is cheaper — $3/$15 per 1M tokens vs Not published.

Which has the bigger context window?

MAI-Thinking-1 — 256K vs 200K, about 1.3× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both Claude Sonnet 4.5 and MAI-Thinking-1 together?

Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, MAI-Thinking-1 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 4.5 or MAI-Thinking-1?

MAI-Thinking-1 — released June 2, 2026, about 8 months after Claude Sonnet 4.5.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.