Rust is fast, both at run and compile time (both important for the speed of the agent loop), its nazi compiler excludes many categories of errors that LLMs might make, the compiler's helpful error messages give precious hints for the agent to iterate upon, it's relatively new so not encumbered with half a century of legacy cruft with obsolete syntax, it has many modern first class features, it neatly compiles into a single portable executable. It's the language that's best positioned to mitigate the issues of LLMs while leveraging their (and its own) strength.