I'm using opencode here's one of the projects I've had it complete - just so you know exactly what it's getting done.

I have a large (300,000k loc) sims-like game that I've hand written over last 3 years.

I have a lot of internal administration tooling that has to be built to manage stuff like icons, NPC brain data, world lore, world actions, all kinds of 3d game data, etc, etc.

One example I had qwen do: Work with me to plan out a feature for an admin panel to manage searchable vector embeddings for each NPC's personality, this was around 600 loc across 4 files, back-end database, front-end UI logic, and front-end templating.

It made 3 small mistakes I told it to sort out and fix, which it did.

I essentially let it do it's thing while I was working on main game core coding. So I was pretty hands off and it planned things out nicely before-hand and got my approvals before it built it.

I really wouldn't call it "glorified auto complete"