Hearth: A Two-Year Solo Prototype for Long-Term Conversational Memory
(July 2024 – present)
A supportive conversational agent I have been building and living with since July 2024. Its memory layer separates writing a new memory from revising an existing one — a PATCH / INSERT write policy rather than an append-only log — so that what the system knows about a person accumulates as a revisable account rather than a transcript. It is where the question my PhD asks stopped being abstract.
CONTRIBUTION
- Sole author: concept, backend, memory architecture, and mobile client. No collaborators, no funding, no publication deadline, and no users other than myself — maintained across two years because I kept returning to it.
- FastAPI backend with a LangGraph-orchestrated conversation graph
- MongoDB memory store with a PATCH / INSERT write policy distinguishing revision from accumulation
- React Native mobile client, used intermittently but continuously since July 2024
RESEARCH RELEVANCE
This is the evidence of sustained devotion I would point to first, precisely because nothing external sustained it. It has one user and no audience. What two years of living with it taught me is that a memory system's hardest failures are not retrieval failures. NBChat would surface something accurate, relevant, and correctly retrieved — and it would still land badly, because it arrived at the wrong moment. Relevance optimisation has no way to represent that error; it has no action for holding, for cueing obliquely, for asking first, or for saying nothing. Naming that error — memory-timing-induced breakdown — and studying it in a population where mistiming carries real cost is the proposal this prototype produced.