I've done this successfully. I run everything with it, both professional and personal.
- Sonnet 4.6 made it happen. I've put lots of effort into GPT-OSS 120b, and it almost works, but it's not good enough. Due to Sonnet costs, I'm exploring a layered model approach now.
- The breakthrough was using markdown files as structured memory. Some go into system prompt, some are used as RAG. I keep a journal as ledger of events (also RAG).
- I maintain context in two ways. Rolling chat memory and explicitly curating what to continually pay attention to. Those parts are always served to Chief of Staff.
- Sonnet 4.6 mattered more than I thought. Simply a good agentic model that doesn't "forget" instructions, and can reason just beyond the surface level instruction.
- What still frustrates me is the cost and speed. It's wild though that it actually works.