Shared Spaces — households, families, classes, teams

A Shared Space is a small group of people who share data implicitly via membership — the membership graph IS the share. Sits next to Personal and Org in the platform's architecture; neither a business entity nor a solo identity.

Four common kinds:

• **Household** — roommates, spouses, partners. Share grocery list, meal plan, household calendar, maintenance reminders.
• **Family** — parents + kids, extended family. Share appointments, school events, chores, family calendar.
• **Class** — students in a course or study group. Share assignments, notes, deadlines, presentation slots.
• **Team** — project collaborators on something that doesn't justify a full org. Share tasks, notes, deliverables.

You can belong to many spaces simultaneously. The membership-graph model means the same recipe can be visible to your household AND your extended-family space if you tag it with both.

To create a space:

1. Open the Shared Spaces section (entry point in your avatar menu — surfacing in Personal Home as well, incrementally)
2. Click "Create a space"
3. Pick a kind, name it (e.g. "The Smiths"), invite members by email
4. Each invitee gets an invitation; once accepted, they're a member and see your space-tagged items immediately

Membership stores at `groups/{groupId}` for the space profile and `groups/{groupId}/members/{uid}` for each member. Items in `users/{uid}/personalEvents`, `users/{uid}/recipes`, and `users/{uid}/groceryList` that carry a `sharedSpaceId` field are visible to every member of that space.

What spaces are NOT:

• Not an organization. There's no admin UI, no payroll, no marketplace, no public-facing surface.
• Not a folder. You don't "move" items into a space — you *tag* them with a space, and the same item can be tagged with multiple spaces (or with none, keeping it private).
• Not a chat. Member-to-member messaging plugs in incrementally; v1 is just the membership graph.

Safety: shared-space membership has a join gate (see Safety Mesh). Users with strong negative safety signals are blocked or flagged-for-review before they can join — protects households and family spaces from cross-space predator patterns.