v3.18.1 — Tabs: give your agent a spending limit it can't exceed

Tabs. Since v3.0.0, @dexterai/x402 grew from a one-shot x402 client into the full Tabs rail: open a capped spending tab for an AI agent, it pays per request with no signature on each charge, and one on-chain settle closes it. Live on Solana mainnet.

Tabs — buyer

• payUrlWithTab — open (or reuse) a lock-protected tab from a URL's own 402 challenge and pay against it.
• resolveTabTerms — read a URL's tab price + settlement terms without paying (consent screens, planners).
• createSolanaVaultAdapter — drive tabs over a passkey-rooted vault.

Tabs — seller

• tabOrExactMiddleware — advertise a tab and a one-shot price in one 402; tab and one-shot callers pay at the same price.
• requireTab + openSse — meter per request (charge / send / await end); you get paid for what you serve and the buyer can't drain mid-stream. You hold no key.

Step-4: lock is the default protection

• Accrued charges crystallize on-chain into a reservation sized to exactly what's accrued — not a whole-wallet freeze. The buyer keeps spending/withdrawing the rest of their balance; the seller is guaranteed the accrued amount. Proven on Solana mainnet (reservation guard, error 0x1781).
• resolveTabTerms reports settlement.protection: 'lock'.

Hardening

• Seller metering uses a durable per-channel ledger (off-chain delivered-cumulative + single-stream lease), closing a reused-tab over-delivery vector.

Install

npm install @dexterai/x402

The on-chain program (Hg3wRaydFtJhYrdvYrKECacpJYDsC9Px7yKmpncj2fhc) is live on Solana mainnet. Pre-audit; audit funding in flight.