PayPal AI Hackathon · live in the PayPal sandbox

The agent can pay.
Only inside the mandate you approve.

TikTato is a live 1v1 tic-tac-toe arena where Tato, a Claude-powered wallet agent, buys coins with your saved PayPal account, with no redirect and never beyond the limits you set.

Try the live demo → ▶ Watch the 2-min demo

Demo login alice545 · Rimpel12 PayPal is already saved and Autopilot is on.

$0received through PayPal (sandbox)

0completed PayPal orders

0🤖 Autopilot charges, no redirect

0agent actions logged

0live matches played

✓ Balancedledger right now

Live numbers from the production database, refreshed on every visit.

The problem

Small top-ups break the game.
Agents could help, if they couldn't overspend.

✍️

Mandate = consent

The player approves exact terms once, in plain words: pack size, refill level, weekly cap and expiry.

🧱

Caps = safety

Every charge is checked on the server. The agent physically can't spend outside the mandate.

🔎

Audit = trust

Every agent action, every coin and every PayPal order is visible in a live dashboard.

Headline feature

Tato Autopilot

Agentic payments under a mandate the player approved.

1
Save PayPal onceVault v3 setup token → the buyer approves on PayPal → payment token. No card or account data is stored.
2
Approve a mandate“Buy a $5 pack when my balance falls below 200 coins, up to $20 per week, for 60 days.” The exact consent text is stored.
3
The agent pays inside itOrders v2 with the saved vault_id: no redirect, and never beyond the mandate.

Pack size and weekly cap from the mandate
At most 3 packs per day
2-minute cool-down, claimed atomically
The player's own weekly PayPal limit
Expiry date and auto-pause after declines
Pause or revoke in one tap

Autopilot mandate card in the wallet: $5 per top-up when below 200 coins, $20 weekly cap — The approved mandate

Tato charging the saved PayPal account for 475 coins with no redirect — A real charge, no redirect

Built deep on PayPal

Every PayPal call runs on the server

The browser never sees a secret, and the server sets every amount and credits it exactly once.

OAuth 2.0

POST /v1/oauth2/token

Client-credentials token. The secret stays in a server-only config.

Orders v2 · create

POST /v2/checkout/orders

Amount set by the server, PayPal-Request-Id idempotency, English experience context.

Orders v2 · capture

POST /v2/checkout/orders/{id}/capture

Checks COMPLETED, amount, currency and reference, then credits once. Handles ORDER_ALREADY_CAPTURED.

Vault v3 · setup token

POST /v3/vault/setup-tokens

The buyer approves saving PayPal for Autopilot. A lost redirect is recovered with GET.

Vault v3 · payment token

POST · DELETE /v3/vault/payment-tokens

Only the token and a masked email are kept. “Remove saved PayPal” deletes it at PayPal.

Off-session order

payment_source.paypal.vault_id

Autopilot charges with no redirect, inside the mandate's caps and cool-down.

Webhooks

POST /v1/notifications/verify-webhook-signature

Signature verified. Handles CHECKOUT.ORDER.APPROVED and PAYMENT.CAPTURE.COMPLETED as a backup credit path.

Exactly-once money

idem_key UNIQUE · WHERE coins >= ?

A double-entry ledger (player, escrow, platform), atomic debits and row-locked settlement.

📱 Player→🤖 Tato proposes→🛡️ Server checks mandate & limits→💳 PayPal Orders / Vault→🧾 Ledger, once

Tato preparing a $10 PayPal checkout card in chat — Tato prepares a checkout and stops: you approve on PayPal.

The AI

Tato, the AI wallet agent

Claude Opus 5.5 through the Anthropic SDK, in a server-side agent loop.

11 strict tools, run for the logged-in player only
Confirm cards for contests and mandates; PayPal approval for checkouts
Server-side fallback on refusals, low effort for fast chat, rate limits
Audit log of every message, tool call and approval
Ask for “free coins” and it can't help: no tool can create coins

get_walletlist_coin_packsstart_paypal_checkoutset_weekly_limitlist_open_contestspropose_contest_actionget_recent_matchesget_autopilotpropose_autopilotautopilot_topup_nowchange_autopilot

And it's a real game

Live 1v1 skill contests

Post an entry, an opponent accepts, both play live. Every move is validated on the server.

TikTato arena with the Play button and live contests — Arena · live contests

Live tic-tac-toe match with prize pool and move clock — Real-time board · 30 s clock

We have a winner screen showing +80 coins — Winner takes the pool − 20%

Entry100

×2 →

Pool in escrow200

−20% →

Winner receives160

DrawFull refund

Also: free practice against a minimax AI, weekly spending limits with a 24 h cool-down to raise them, 18+ only.

Trust

Every action is auditable

A live AG Grid dashboard: agent actions, the double-entry ledger, PayPal orders (🤖 Autopilot vs checkout) and matches, with filters, search, totals and CSV export.

Activity and audit dashboard built with AG Grid, showing KPI tiles and the ledger

2:33 demo

Watch it work, live footage only

For judges

Test it in 5 minutes

Log in as alice545 and tap Ask Tato: “What's my balance?”
Say “Top me up now”. Autopilot charges the saved PayPal with no redirect. Say it again, and the cool-down refuses.
Say “Buy $10 of coins” to get a real PayPal sandbox checkout. Pay with any sandbox personal account.
Post a contest. In a private window, log in as judge_blue and accept it. Play it out.
Open Activity → Platform: every agent action, PayPal order and ledger row, with “ledger balanced ✓”.

Account	Password	Use
alice545	`Rimpel12`	Main demo · Autopilot on · admin view
judge_blue	`TikTato-Judge-2026`	Second player
judge_red	`TikTato-Judge-2026`	Set up Autopilot from scratch

Open the live demo Code on GitHub (MIT)

The agent can pay.Only inside the mandate you approve.

Small top-ups break the game.Agents could help, if they couldn't overspend.