Is Julia still as relevant in the age of AI agents?

I would think you could implement those 200 lines also in Julia with (or without!) AI. And you can already call Julia from R; and with this package it will likely get easier as it already has for Python to call Julia:

R is likely next, and AI has been helping greatly recently in the Julia ecosystem as with the MATLAB support (and at JuliaLang and elsewhere), here with 45 commits across 30 files:

I still think Julia is the better language for, and if you’re language agnostic, you might be able to move everything to Julia. AI can probably already do it as has been shown in other cases (in one recent case of large codebase translation by AI for C++ to Julia resulted in 6x speedup):

Now it’s a question of which is the best language.

Depending on exactly what you’re doing this might apply:

Same AI model, different results: Dyad Agent scored 0.899 versus Claude Code’s 0.533 across four physics problems, at similar cost and runtime.