As of: 2026-10-23 13:24 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/p/x-anthropicai-2113390212911083894/

# “New on our Frontier Red Team blog: using Claude to formally verify software at large…”

Anthropic (@AnthropicAI), X, 2026-10-22.
Source: https://x.com/AnthropicAI/status/2113390212911083894

## Archived text

> New on our Frontier Red Team blog: using Claude to formally verify software at large scale.
> 
> Formal verification can prove that code is free of certain bugs, but historically it has only been feasible for small codebases (or required a lot of expert time).
> 
> With AI models, however, this is beginning to change. In collaboration with @theoremlabs, we used Claude to prove security properties in over one hundred real-world open-source libraries over the span of a few weeks.
> 
> Read our research in full here: https://www.anthropic.com/research/formal-verification

Archived 2026-10-23 via fxtwitter (unofficial).
Counts: 1,064,084 views, 6,929 likes, 701 reposts, 442 replies (at fetch time)

## Cited in

- 2026-10-22: [Claude formally verifies 123 open-source libraries](https://postcutoff.com/e/2026-10-22-anthropic-formal-verification-oss-fuzz-rocq/)