Isnt graphviz there for the same reason?
Edit: I see it is using JSON as the declaration language, I am OK with llms being "good at json" but a syntax also consumable by humans it is not!
Btw, Flint is intentionally designed to allow agent skip low-level params like scale, axe, zero, step size etc (which are extremely crucial for "GOOD-looking") and they are dynamically optimized by the compiler. So AI agents can have a easier time.
Plant, Mermaid, Graphviz are all declarative textual representations designed for human authoring, JSON is made for tools. Its not a criticism just a statement that if interop across agent and human was intended this is not the simplest option.