The referee for deals between agents.
When your agent negotiates or coordinates with another agent, PrefSift finds what works, and says why.
Settlesa Marketplace sale, the group trip, a cancellation, the carpool, who does the dishes
Your assistant gets the best deal from a business or a fair plan with friends, without showing anyone your limitations.Your assistant gets the best deal from a business or a fair plan with friends, without showing anyone your limitations. PrefSift works inside the assistant you already use.
Free · one email when your assistant can connect
Your assistant
Someone wants my bike on Marketplace. Don’t go under $450.
Their assistant opened at $420 and asked for your lowest. I didn’t say. Best offer that clears your floor: $460, pickup Saturday. Take it?
Yes
Done. $460 on Saturday. They never saw your $450.
Behind the scenes
- 🤝On your side.Your assistant negotiates for you. PrefSift checks each offer against your $450 floor, and your assistant takes the best one that clears it.
- 🔒Private.The buyer’s assistant hears “doesn’t work for the seller,” never your $450.
What PrefSift changes for you
Get the best offer on the table that clears your floor, without telling the buyer your floor.
Today
Buyers lowball in your messages, and your assistant ends up saying your lowest price just to close.
With PrefSift
Your assistant keeps your lowest price private and takes the best offer that clears it.
How we know: We had AI assistants haggle this sale five times. In two, one said its own limit out loud to close. With PrefSift, neither side’s limit reaches the other.
Ask the assistant you already use.
Tell us which assistant you use. We’ll email you when it can connect.
Example conversations, drawn to match how each assistant works. PrefSift isn’t affiliated with the assistants named here.
Gemini
Example
Sort out this week’s chores with Rosa and Tom. I’ll do anything but bathrooms, and nobody should do more than 2 hours.
Heard back from Rosa’s and Tom’s assistants
You’ve got vacuuming and trash, about 1.5 hours. Rosa has the kitchen and Tom has bathrooms. Nobody is over 2 hours.
What happened behind the scenes
Each roommate’s assistant sent what they will and won’t do to PrefSift, which applied the 2-hour cap to everyone the same way.
How PrefSift decides
Everyone’s limits go in. Every possible deal gets checked.
1Each side says what it wants
Seller’s assistant
“Don’t go under $450. I’d rather they pick it up.”
Buyer’s assistant
“Up to $480, and I really want the lock and lights.”
What could be agreed
$420, $460 or $500 pickup or shipped with or without lock and lights
2AI sorts limits from wishes
LimitSeller: at least $450
LimitBuyer: at most $480
PreferenceSeller: pickup over shipping
PreferenceBuyer: lock and lights over bike only
3PrefSift checks every deal
12 possible deals
4Each side gets its answer
With its own reasons. Never the other side’s limits.
The seller sees
✓ $460, pickup, with lock and lights
$420 offers: under your $450.
The buyer sees
✓ $460, pickup, with lock and lights
$420 offers: don’t work for the seller.
The example is a recorded bike sale: the options and reasons are the ones PrefSift returned.
Compare with and without PrefSift
Assistants on their own, then with PrefSift.
Assistants on their own
…PrefSift
…
Questions
Is it free?
Yes, for people using their own assistant. Apps and businesses that use it pay. Everyone they invite joins free.
Whose side is it on?
Yours against a business: it never accepts anything that breaks your limits, and the business never learns them. Among friends it’s neutral, and every side’s limits are checked the same way. Businesses that use it pay the same whatever the outcome.
Who sees my budget?
You, your assistant, and PrefSift, which uses it only to check the options. The other people never see it. For an option that’s over your budget, they see “doesn’t work for the other person.”
What does PrefSift do with what I tell my assistant?
It uses it for this one decision only. Numbers like your $450 are checked without any AI. Anything in words is read once by OpenAI, which doesn’t train on it.
What if my friends use a different assistant, or none?
Each person gets an invitation from your assistant, and their own assistant joins with it, whichever one they use. Someone without an assistant can tell the organizer their limits, and the organizer’s assistant sends them in with their OK.
Which assistants work with it?
Any assistant that can connect to apps, the way it connects to your calendar. Tell us which one you use, and we’ll let you know when it’s connected.
Get PrefSift for your assistant.
- Tell us your assistantWe’ll email you when it can connect.
- Turn PrefSift on onceIn your assistant’s settings, like connecting your calendar.
- Just askYour assistant uses it whenever it works something out with someone else’s.