Microsoft used AI to rewrite the Copilot runtime in Rust for $120,000

Sep 21, 2026 · Issue 8 · 7 sources, 7 articles

According to reports on September 21, Microsoft used artificial intelligence to rewrite the Copilot runtime: 800,000 lines of Rust code were produced for $120,000. The reports cite a performance gain of nearly 16x.

Who is affected and how

CTO

The cost and performance figures can support business cases for AI-assisted migration, but the source should be verified.

tech lead

Consider which legacy components could be earmarked for an AI-driven rewrite and how the result can be measured.

senior developer

Expect review and testing to be the main work in a large-scale rewrite.

Narrative: Software factory: agents now write code

Sources

• Microsoft uses AI to rewrite Copilot runtime: $120,000 for 800,000 lines of Rust code, nearly 16x performance boostbiggo finance · Sep 21, 2026
• Microsoft will get a boost from Azure and Copilot, Stifel sayscnbc.com · Sep 23, 2026
• Microsoft overhauls Copilot with Home, Code, and Autopilottechzine global · Sep 25, 2026
• New Microsoft Copilot Brings Home, Code, and Autopilot Together - Source EMEAnews.microsoft.com · Sep 25, 2026
• Introducing the new Copilot with Home, Code and Autopilot - The Official Microsoft Blogblogs.microsoft.com · Sep 25, 2026
• Microsoft Copilot Managed Runtime: Enterprise code execution for Microsoft 365 | Microsoft Copilot Blogmicrosoft.com · Sep 25, 2026
• Microsoft is restructuring Copilot with a focus on enterprise AI :: RE:UKRAINEre-ukraine.com · Sep 25, 2026

Machine-generated summary based on the titles and excerpts of the source articles. The facts come from the linked article.