# @agenttrust-sdk/trustgate (/sdk)



The SDK is the facilitator-facing TypeScript package.

```bash
pnpm add @agenttrust-sdk/trustgate
```

## Imports [#imports]

```ts
import { mountTrustGate } from "@agenttrust-sdk/trustgate/express";
import { gatePayment, settle, dispute } from "@agenttrust-sdk/trustgate/client";
import {
  AtomicityNotEnforcedError,
  DEFAULT_DEVNET_PROGRAM_IDS,
  derivePolicyPda,
} from "@agenttrust-sdk/trustgate";
```

## gatePayment [#gatepayment]

`gatePayment()` is a read-only decision call.

```ts
type GateDecision =
  | { kind: "Allow" }
  | { kind: "Deny"; reasonCode: number; reasonName: string }
  | { kind: "RequireValidation"; capabilityHash: number[] };
```

The helper simulates the Anchor instruction and parses the return-data channel into the TypeScript union.

## mountTrustGate [#mounttrustgate]

`mountTrustGate(app, config)` adds x402 routes to an Express service in fewer than 50 lines.

```ts
await mountTrustGate(app, {
  rpcUrl: "https://api.devnet.solana.com",
  facilitatorKeypair,
  defaultPolicyId: 1,
  network: "solana-devnet",
  atomicityEnforced: true,
});
```

## Atomicity guard [#atomicity-guard]

`settle`, `dispute`, and middleware config require:

```ts
{ atomicityEnforced: true }
```

The marker is literal `true`, not `boolean`, and the runtime guard throws if a caller bypasses TypeScript with a cast.

## v0.1 surface [#v01-surface]

| API                         | Status                                       |
| --------------------------- | -------------------------------------------- |
| `gatePayment`               | implemented                                  |
| `mountTrustGate` `/verify`  | implemented                                  |
| `mountTrustGate` `/receipt` | implemented                                  |
| `settle`                    | guarded surface, transaction builder follows |
| `dispute`                   | guarded surface, transaction builder follows |

Source: `trustgate/sdk/src`.