Microsoft has released Microsoft-Decision-1, a small model that picks between fixed answer options instead of writing text. Microsoft built it on Alibaba’s open-weight Qwen3.5-9B and then post-trained it, according to the Foundry model card.
Achint Srivastava, a vice president of software engineering in Microsoft’s Office of the CTO, announced the model in a blog post on 9 October. Microsoft will soon rebase it on other models, including OpenAI’s and its own MAI models, he wrote. The post does not say why.
“Decision models are quickly emerging as an important new category in AI,” Srivastava wrote.
What the model does
Given a fixed set of options, Microsoft-Decision-1 returns a calibrated probability score for each one. It handles yes or no questions, multiple choice and ratings. It can also grade AI responses and agent actions against a rubric.
Microsoft lists uses such as routing, classification, prioritisation, verification and workflow control. The model takes text only and has a 32,000-token context window, the model card says. It should not be the sole basis for consequential decisions about people, such as credit or employment, the card adds.
Microsoft’s own benchmarks
Microsoft said the model scored the highest accuracy in its 36-benchmark comparison. That covered nearly 150,000 questions kept blind from training.
In its tests, the model was 2.5 times faster than the runner-up, H2O-Lightning-4B v1.1. It was 35 times faster than OpenAI’s GPT-6 Sol. When Microsoft reworded or reordered the same request, the model changed its decision 1.3% of the time on average.
Microsoft also tested it on 5,250 requests across 11 safety benchmarks. These covered harmful content, jailbreak attempts and prompt injection.
Internal tests and pricing
Xbox Research used the model to sort more than 10,000 pieces of player feedback and reviews into themes. Microsoft said it was competitive with GPT-6 Sol on quality, over 14 times faster and 200 times cheaper. The Copilot team found it competitive with GPT5.6 Luna and 100 times faster.
Input costs $0.042 per million tokens, and output tokens are free. The model is available in Microsoft Foundry and through OpenRouter, the model router Stripe bought in August.
A crowded category
Microsoft later updated its post to add benchmarks for Jev, from TypeSafe AI. Jev launched three weeks before Microsoft’s model, as Thomas Claburn reported for The Register. It became the fastest-adopted model on Vercel this year. Microsoft said its model was 2.8 times faster than Jev in its latency test, The Register reported.
OpenAI’s Decisions API is in public beta. Cloudflare, Strands, Liquid AI, Perplexity and Snowflake have also announced decision models, according to The Register. More than 100 such models now compete for attention, the outlet said.