For me the answer is twofold.

Regarding commercial solutions:

- Subscription: Google AI Ultra (testing for 1 month rn to see what i can get out of argon, after that probably going back to Pro package)

- Harness: Antigravity IDE : from what i have tested on commercial harnesses this one i liked the most so far

Regarding selfhosted solutions:

- Inference host: Im owning a 5090 and im running the models locally - mostly use qwen 3.8 27b q5 atm, its a bit "slower" even on a 5090 but it fits the vram i have available while also being quite good in terms of result quality

- Harness: I tested alot and ended up writing my own harness ( https://github.com/laughingmandev/loa ) since none of the ones i tested (yes i tested openhands, hermes, etc...) did work well for me. While my own harness still needs some enhancements, its especially made for long running / complex tasks while beeing hands off (not permanently prompt jokey'ing ) and sturdy enaugh to work well with selfhosted/local run inference.

I use the gemini4argon/google agent atm to work on a c++ simulation and image asset generation for a game im working on. The complexity of this stuff just is to big for a local qwen 3.8 to fully grasp (its not that good at c++ either). Local image diffusion also is not that great.

For other stuff of low to medium complexity im working with my own agent/harness/setup - especially if the data is anyhow security relevant since im not leaking anything outside. From writing scripts/tools to analyzing infrastructure or discussing architecture.