for friends, partners, groups making plans together
Group Trip
Friends planning a trip without flooding the group chat. Cast keeps each person's research private, the shared plan curated, and pulls everyone's preferences together when it's time to pick.
group-trip
14:08
where are we eating in porto saturday night?
14:08
👥grouppreferences gathered from 4 members
🍴cuisine signaltraditional Portuguese (3 of 4)
💸budget signal€10–25 / head feasible for everyone
📍location signalnear São Bento (2 of 4)
Three picks that fit the group:
· Cervejaria Gazela — €18/head, two-block walk from São Bento. Traditional petiscos, well-loved.
· O Buraco — €12/head, slight walk. Cheap traditional, busy with locals.
· Casa Guedes — €10/head, near São Bento. Famous for slow-roasted pork sandwich; single-dish place.
Want me to put it to a vote, or pick one?
preferences gathered privately · only the synthesis goes to the group
The situation
Three friends planning a trip to Portugal in October. Different budgets, different obsessions, different ideas of what makes a good vacation. Group chats devolve into noise. Spreadsheets get abandoned. Cast keeps each person's research and preferences private to them, curates the shared itinerary, and weighs everyone's input when the group needs to decide between options. Different opinions, one plan, less arguing.
How it behaves
One assistant for the whole group, with private space for each of you.
Private research per person — Sam's restaurant lookups, Priya's hike notes, your own destination and museum thinking. None of it leaks across
Shared itinerary, curated — destinations, dates, accommodations, agreed-on activities. Anyone can see, anyone can suggest, the assistant keeps it tidy
Group decisions, synthesized — when it's time to pick a restaurant or a flight, it pulls everyone's privately stated preferences into a short list with rationale
Each friend on the app they actually use — Sam on Telegram, Priya on Slack, you on the web. Same assistant, different doors
The two guarantees aren't the same kind. Each person's research sits behind a wall the others can't cross, including you, the organizer. The assistant just keeps the shared itinerary tidy.
How you'd build it
Setting up the group
group-trip
Three of us are planning a trip to Portugal in October — me, Sam, and Priya. We've got different budgets and very different ideas about what makes a good trip (Sam's all food, Priya hikes, I want some of both plus museums). Can you set us up something that helps without turning into another spreadsheet?
design
Yeah. Here's what I'd propose:
· you three as the people who can talk to it
· each of you has a private space — your own research, preferences, budget thoughts stay yours
· a shared itinerary the assistant curates — destinations, dates, accommodations, what's been agreed
· synthesis on demand — when you need to pick a restaurant or a hostel, it pulls everyone's preferences and budgets into a short list
A couple of things to nail down:
· Anyone in the group leading on logistics (booking, payments), or is that flexible?
· How tight is the budget conversation — should the assistant know each person's max, or stay neutral and surface ranges?
I'm leading on logistics — bookings, AirBnB hold, the group flight. On budgets: Priya's tight, Sam and I are middle. I'd rather the assistant know each cap privately and default to options that fit the tightest budget, with a way for people to opt up if they want.
design
Locked in:
· you: organizer; bookings and payment confirmations route to you, the others see decisions as they're made
· each person tells the assistant their max privately; default option set fits the tightest budget so nobody feels priced out
· anyone can ask 'show me higher tier' and it'll surface those for them only — others don't see those unless the group explicitly opts in
That's the assistant's brain. Connecting each of you to it lands in configure once we wrap.
The opening of the design conversation isn't 'how should this be built' — it's 'who's in this group and what's the trip about.' You sketch the friends and the dynamics; Cast translates that into a structure. Notice the user describes the people and their differences, not the architecture; the questions Cast asks back are about the group's needs, not Cast's mechanics.
Designing how the group decides
group-trip
When we need to pick something — like which AirBnB in Lisbon, or where to eat Saturday night — what does the assistant actually do?
design
Two patterns I'd build in:
· Quick pick — short list of three options that fit the group's preferences and budget. Each carries a one-line rationale ('matches the group's stated cuisine preferences, fits the tightest budget, two-block walk from the AirBnB'). You decide quickly or vote.
· Deep pick — when it matters more (the AirBnB, the rental car, the long ferry day), I'd gather each of your asks privately, show the group an anonymized synthesis ('three of you flagged proximity to Time Out Market, two prioritized walkability, one wants AC'), then propose options.
Both modes preserve the privacy contract — your individual asks stay yours; only the synthesis goes to the group.
Default to deep pick on accommodations and big spends; quick pick on day-to-day stuff like restaurants and activities. And if we can't agree, I want the assistant to say so honestly — not push us toward fake consensus.
design
Set:
· accommodations, transport, anything over €100/person — deep pick, full synthesis
· day-to-day — quick pick, three options, no synthesis writeup
· when preferences split (e.g., two want hiking, two want beach for Saturday) — I'd surface the split honestly with each side's reasoning, suggest a tiebreaker (compromise day, voting, alternating), but not push consensus
I'd start opinionated about tiebreakers and we'd refine in the first few decisions based on what the group actually does.
The whole point of the assistant is helping the group decide without devolving. That means designing how it handles decisions — when to recommend, when to vote, what to do when you can't agree. The user describes what kinds of decisions the group faces; Cast proposes patterns it can use.
Connecting each friend
group-trip
How does each friend actually reach the assistant? Sam only checks Telegram, Priya basically lives in Slack, and I'd just use the web.
design
Each person reaches the same assistant through whichever transport they actually use. The assistant doesn't change. Only how each person reaches it does.
· Sam → Telegram
· Priya → Slack
· you → web
Same conversation lane for all of you (the default), different transports per person. Each only ever sees their own private space and the shared itinerary. Access happens in configure once we wrap design here: each person messages from their own transport, and you approve them the first time. Handles are per-deployment, so it's deployment work, not design.
What if Sam loses his phone, or wants to add WhatsApp later? And if a fourth friend joins mid-planning — any limit?
configure
All configure-console things, all straightforward:
· Sam loses his phone: same Telegram account on the new one, and he's recognized automatically. His identity and threads stay his.
· Sam adds WhatsApp later: he messages from it, you approve that first contact, and both Telegram and WhatsApp now reach his identity.
· A fourth friend joins mid-planning: I'd let them in like the others. You decide what they see (probably the shared itinerary plus their own private space, probably not retroactive group decisions if you want to keep that intentional).
None of these change the assistant. It's all in the identity-and-transport layer.
Designing the assistant is one thing; getting each friend actually connected to it is another. That handoff lives in the configure console, separate from the design, because granting each person access on the transport they actually use is per-deployment operator work, not part of who the assistant is.
What stays separate
Cast enforces per-person privacy. Sam's research is Sam's, Priya's budget concerns are Priya's, and even as the organizer you can't see what each of them is exploring. The shared itinerary works differently. The assistant curates it according to its instructions, surfacing what's been decided and holding open questions until the group agrees. Two kinds of separation: a hard wall on private research, and curated discipline on shared plans.
weekly digest: this week's decisions, this week's open questions, anyone's ideas worth circulating
Blueprint highlight
One assistant for the group: private research per person, shared itinerary curated by the assistant, synthesis when the group needs to decide
Build it yourself
Install Cast, then describe this in the admin chat. The Design agent writes the agents, conversations, and ACL for you. The extensions you'd need are listed above.