A personal journaling system with an API. Capture on the phone, review on the web, and let an AI assistant read and write the same entries — no export step, no copy-paste.
Years of notes are worth nothing if the only way to use them is scrolling. Synapstack OS treats the journal as a database with a proper API, then hands an AI assistant a scoped key to it. Ask a question in Claude and it searches the actual entries. Tell it something worth keeping and it writes the entry itself.
Everything lands in the same D1 database. The MCP server is a second Worker with its own auth, so an AI client never touches the app's session.
Read tools work with a read-only grant. Write tools require read-write. There is no delete tool in v1 — an agent that can't delete can't quietly erase a decade of entries during a bad reasoning chain.
The working tree lives in OneDrive, so a committed .env would sync straight to someone else's cloud. Worker tokens live only in Cloudflare; API keys live only in the iOS Keychain. The rule is the point — the gitignore is just enforcement.
The web companion runs its own invite code plus Google or Apple sign-in. A separate edge access gate on top of that was redundant, so it came off — with a one-click restore path kept in place.
A WAF rule throttles credential hammering at the door. The real fix — failed-attempt lockout with exponential backoff — belongs in the Worker, where there are no plan limits on the counter.
Phone, browser, and AI assistant all read the same D1 rows through the same sync engine. Nothing is a mirror or an export, so nothing drifts.