Curious if others here are going beyond single-domain MCP servers and building full personal-OS style systems.
I spent the last few months building Sathi — one MCP exposing 70+ tools across 8 pillars (memory, tasks, habits, goals, finance, documents, skills, cross-pillar graph). The demo video in this post walks through a real day of using it.
A few things I'd genuinely love the community's take on:
**Tool surface area** — I landed on a query_X / manage_X pattern per pillar (~19 top-level tools fronting 64 logical ops). Is that too many? Too few? How are you organizing yours?
**State management** — I went fully stateless (re-auth every call) so parallel clients don't collide. Some folks swear by stateful. What's working for you?
**Cross-entity links** — I added a graph pillar so a task can reference a memory can reference a goal. Overkill for a personal tool? Or is this the actual unlock?
Stack: Next.js 16, Postgres + pgvector, MCP SDK.
Live: https://sathi.devfrend.com
Not trying to sell anything — genuinely want to compare notes with other MCP builders.