I'm presently in the process of building (read: directing claude/codex to build) my own AI agent from the ground up, and it's been an absolute blast.

Building it exactly to my design specs, giving it only the tool calls I need, owning all the data it stores about me for RAG, integrating it to the exact services/pipelines I care about... It's nothing short of invigorating to have this degree of control over something so powerful.

In a couple of days work, I have a discord bot that's about as useful as chatgpt, using open models, running on a VPS I manage, for less than $20/mo (including inference). And I have full control over what capabilities I add to it in the future. Truly wild.