### Install Rust + WASM Toolchain

Source: https://docs.terminal3.io/developers/adk/get-started/prerequisites/set-up-dev-env

Install the WASI Preview 2 build target and optionally the wasm-tools for inspecting WASM binaries.

```bash
rustup target add wasm32-wasip2          # WASI Preview 2 build target
cargo install wasm-tools                 # optional — inspect/verify the component
```

--------------------------------

### Install wasm-tools

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/build-contract

Installs the `wasm-tools` utility, which is used to inspect WebAssembly components.

```bash
cargo install wasm-tools
```

--------------------------------

### Tenant-Owned Namespace Example

Source: https://docs.terminal3.io/t3n/how-t3n-works/z-namespace

Provides a concrete example of a canonical tenant-owned namespace, showing a specific tenant DID suffix and a map name.

```text
z:8f3a0123456789abcdef0123456789abcdefc91d:secrets
```

--------------------------------

### Install the T3N SDK

Source: https://docs.terminal3.io/developers/adk/get-started/prerequisites/set-up-dev-env

Install the Terminal3 SDK package using npm. Node.js version 18 or higher is required.

```bash
npm install @terminal3/t3n-sdk
```

--------------------------------

### Verifiable Credential (VC) JSON-LD Example

Source: https://docs.terminal3.io/intro/components/vc

An example of a Verifiable Credential formatted in JSON-LD, including context, issuer, issuance date, and credential subject.

```json
{
  "@context": [
    "https://www.w3.org/2018/credentials/v1"
  ],
  "id": "https://app.terminal3.io/credentials/58473",
  "type": ["VerifiableCredential", "UniversityDegreeCredential"],
  "issuer": "did:key:terminal3",
  "issuanceDate": "2023-01-01T00:00:00Z",
  "credentialSubject": {
		"id": "did:ethr:0xebfeb1f712ebc6f1c276e12ec21",
	    "degree": {
	      "type": "BachelorDegree",
	      "name": "Bachelor of Science and Arts"
	    }
	},
  "proof": { ... }
}
```

--------------------------------

### DID Document Example

Source: https://docs.terminal3.io/intro/components/did

This JSON object represents a DID document, which contains information associated with a DID, such as cryptographic authentication methods. It includes the DID context, the DID itself, and authentication details.

```json
{
  "@context": [
    "https://www.w3.org/ns/did/v1",
    "https://w3id.org/security/suites/ed25519-2020/v1"
  ]
  "id": "did:example:123456789abcdefghi",
  "authentication": [{
    "id": "did:example:123456789abcdefghi#keys-1",
    "type": "Ed25519VerificationKey2020",
    "controller": "did:example:123456789abcdefghi",
    "publicKeyMultibase": "zH3C2AVvLMv6gmMNam3uVAjZpfkcJCwDwnZn6z3wXmqPV"
  }]
}
```

--------------------------------

### Add WASI Preview 2 Target and Build Release Artifact

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/build-contract

Installs the `wasm32-wasip2` target and builds the Rust contract as a release artifact. Ensure you have `crate-type = ["cdylib", "lib"]` in your `Cargo.toml`.

```bash
rustup target add wasm32-wasip2
cargo build --target wasm32-wasip2 --release
```

--------------------------------

### Authenticate to T3N Testnet and Get Tenant DID

Source: https://docs.terminal3.io/developers/adk/get-started/prerequisites/set-up-dev-env

Authenticate to the T3N testnet using the T3nClient and retrieve the tenant DID from the authenticated session. This DID must match the one admitted as a tenant.

```typescript
await t3n.handshake();
const did = await t3n.authenticate(createEthAuthInput(address));
const tenantDid = did.value; // did:t3n:<your-random-hex> — your onboarding DID
```

--------------------------------

### Set up T3nClient

Source: https://docs.terminal3.io/developers/adk/get-started/prerequisites/set-up-dev-env

Initialize a T3nClient instance, setting the environment, loading the WASM component, and providing the EthSign handler for authentication.

```typescript
import {
  T3nClient,
  TenantClient,
  setEnvironment,
  loadWasmComponent,
  eth_get_address,
  metamask_sign,
  createEthAuthInput,
  getNodeUrl,
} from "@terminal3/t3n-sdk";

setEnvironment("testnet");   // "testnet" | "production" — the SDK resolves the node URL for every client

const T3N_API_KEY = process.env.T3N_API_KEY!;   // your developer key from the claim page

const wasmComponent = await loadWasmComponent();   // all crypto runs inside the WASM component
const address = eth_get_address(T3N_API_KEY);

const t3n = new T3nClient({
  wasmComponent,   // no baseUrl — resolved from the active environment
  // EthSign is the only handler you provide — it signs the login challenge with
  // your key. The client adds the MlKemPublicKey and Random handlers itself.
  handlers: {
    EthSign: metamask_sign(address, undefined, T3N_API_KEY),
  },
});
```

--------------------------------

### Importing Host Interfaces in world.wit

Source: https://docs.terminal3.io/developers/adk/tips/capabilities-from-wit-import

This WIT code demonstrates importing host interfaces like kv-store, logging, tenant-context, and http-iface. Importing `http-iface` enables outbound HTTP requests for your contract.

```wit
world your-contract {
  import t3n:host/kv-store@0.1.0;
  import t3n:host/logging@0.1.0;
  import t3n:host/tenant-context@0.1.0;
  import t3n:host/http-iface@0.1.0;   // ← opting into outbound HTTP
}
```

--------------------------------

### Rust Contract Entry Point (lib.rs)

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/write-contract

Implements the `Guest` trait for the contract's dispatch function. It routes incoming calls to specific functions like 'search-offers' or 'book-offer' based on the input.

```rust
wit_bindgen::generate!({ world: "contract", path: "wit" });
use exports::t3n::contract::dispatch::{Guest, ContractInput, ContractOutput, ContractError};

struct Component;

impl Guest for Component {
    fn dispatch(input: ContractInput) -> Result<ContractOutput, ContractError> {
        match input.function.as_str() {
            "search-offers" => search::search_offers(input),  // no PII — plain http
            "book-offer"    => booking::book_offer(input),    // PII via http-with-placeholders
            other => Err(ContractError::UnknownFunction { name: other.to_string() }),
        }
    }
}

export!(Component);

```

--------------------------------

### Build TenantClient

Source: https://docs.terminal3.io/developers/adk/get-started/prerequisites/set-up-dev-env

Construct a TenantClient instance using the authenticated T3nClient, the active node URL, and the tenant DID. The TenantClient is used for managing your own deployment.

```typescript
const tenant = new TenantClient({
  t3n,
  baseUrl: getNodeUrl(),   // the active node from setEnvironment(); Call `setEnvironment("testnet")` (or `"production"`) — the SDK resolves the cluster URL for every client, so you never hardcode a node URL.
  tenantDid,
});
```

--------------------------------

### Print Component WIT Interface

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/build-contract

Uses `wasm-tools` to display the WebAssembly component's WIT interface, showing imported host interfaces and the contract entry point.

```bash
wasm-tools component wit target/wasm32-wasip2/release/your_contract.wasm
```

--------------------------------

### Rust Contract Using http-with-placeholders

Source: https://docs.terminal3.io/developers/adk/tips/placeholders-outbound-calls

This Rust code demonstrates how to construct a JSON body with profile placeholders and make an outbound HTTP POST request using the `http-with-placeholders` host interface. The host resolves `{{profile.<path>}}` markers from the calling user's profile before the request is sent.

```rust
use crate::bindings::t3n::host::http_with_placeholders as hwp;

// The {{profile.<path>}} markers are resolved host-side from the calling
// user's profile — this contract never sees the plaintext values.
let body = serde_json::json!({
    "data": {
        "type": "instant",
        "selected_offers": [req.offer_id],
        "passengers": [{
            "id": "passenger_0",
            "given_name":  "{{profile.first_name}}",
            "family_name": "{{profile.last_name}}",
            "born_on":     "{{profile.date_of_birth}}",
            "email":       "{{profile.verified_contacts.email.value}}",
        }]
    }
});

let resp = hwp::call(&hwp::Request {
    method:  "POST".to_string(),
    url:     "https://api.duffel.com/air/orders".to_string(),
    headers: vec![
        ("Authorization".to_string(), format!("Bearer {api_key}")),
        ("Duffel-Version".to_string(), "v2".to_string()),
        ("Content-Type".to_string(), "application/json".to_string()),
    ],
    body: Some(serde_json::to_vec(&body)?),
})?;
// resp.body — Duffel's response (booking id + PNR). The passport/name/DOB
// were substituted by the host; your WASM never held them.
```

--------------------------------

### Rust Search Offers Function (search.rs)

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/write-contract

Handles 'search-offers' requests using synchronous HTTP calls to an external API. This function is designed to not handle PII directly, making it suitable for plain HTTP requests.

```rust
use crate::bindings::t3n::host::{http_iface, logging};

pub fn search_offers(input: ContractInput) -> Result<ContractOutput, ContractError> {
    let req: SearchOffersRequest = serde_json::from_slice(&input.payload)
        .map_err(|e| ContractError::InvalidInput { detail: e.to_string() })?;
    let api_key = duffel_api_key()?;

    // Synchronous HTTP — the response is available in the same call (no PII in flight).
    let resp = http_iface::call(&http_iface::Request {
        method: "POST".to_string(),
        url: "https://api.duffel.com/air/offer_requests?return_offers=false".to_string(),
        headers: vec![
            ("Authorization".to_string(), format!("Bearer {api_key}")),
            ("Duffel-Version".to_string(), "v2".to_string()),
        ],
        body: Some(serde_json::to_vec(&req)?),
    })?;

    logging::info("searched offers");
    Ok(ContractOutput { payload: resp.body })
}

```

--------------------------------

### Invoke TEE Contract Functions with T3nClient

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/invoke-contract

This snippet demonstrates how an agent uses the `T3nClient` to authenticate and invoke functions on a TEE contract. It includes searching for offers and booking a selected offer, highlighting how PII is handled server-side via `http-with-placeholders`.

```typescript
import {
  T3nClient,
  loadWasmComponent,
  createEthAuthInput,
  eth_get_address,
  metamask_sign,
  getScriptVersion,
  getNodeUrl,
} from "@terminal3/t3n-sdk";

const agentKey = process.env.AGENT_KEY!;
const agentAddress = eth_get_address(agentKey);

const agentClient = new T3nClient({
  wasmComponent,   // node URL resolved from setEnvironment() — see set-up-dev-env
  handlers: {
    EthSign: metamask_sign(agentAddress, undefined, agentKey),
  },
});

await agentClient.handshake();
await agentClient.authenticate(createEthAuthInput(agentAddress));

const TENANT_SCRIPT = `z:${tenantDid.slice("did:t3n:".length)}:travel/contracts`;
const scriptVersion = await getScriptVersion(getNodeUrl(), TENANT_SCRIPT);

// 1. Search for offers (no PII)
const search = await agentClient.executeAndDecode({
  script_name: TENANT_SCRIPT,
  script_version: scriptVersion,
  function_name: "search-offers",
  input: { origin: "LHR", destination: "JFK", departure_date: "2026-07-15", cabin_class: "economy", adult_count: 1 },
});
const offer = search.offers[0];

// 2. Book the chosen offer. No PII in the input — name, DOB and email are
//    resolved host-side from the user's profile via http-with-placeholders,
//    and only when the user's grant authorizes this agent (see the grant above).
const booking = await agentClient.executeAndDecode({
  script_name: TENANT_SCRIPT,
  script_version: scriptVersion,
  function_name: "book-offer",
  input: {
    offer_id:       offer.id,
    passenger_id:   offer.passenger_ids[0],  // opaque Duffel id from search — not PII
    total_amount:   offer.total_amount,
    total_currency: offer.total_currency,
  },
});
// booking.pnr → the flight booking reference. The passenger's name never left the enclave.
```

--------------------------------

### TEE Node Execution Flow Sequence Diagram

Source: https://docs.terminal3.io/t3n/how-t3n-works/tees

Illustrates the sequence of operations for executing a TEE contract on a T3N node, from client request to encrypted response, including data fetching and decryption steps.

```mermaid
sequenceDiagram
    participant C as Client
    participant TEE as TEE Node
    participant CAS as CAS (External Storage)
    participant KV as KV Store

    C->>TEE: action.execute(encrypted request)
    TEE->>TEE: Decrypt request 
    TEE->>KV: Get user profile ValueRef by DID
    KV-->>TEE: ValueRef (CID, storage location)
    TEE->>CAS: Fetch encrypted profile blob by CID
    CAS-->>TEE: Encrypted profile blob
    TEE->>TEE: Decrypt profile (AES-256-GCM with cluster CEK)

    TEE->>KV: Resolve TEE contract ValueRef from registry
    KV-->>TEE: TEE Contract ValueRef
    TEE->>CAS: Fetch TEE contract by CID
    CAS-->>TEE: TEE contract

    TEE->>TEE: Execute TEE contract (profile, input) in sandbox
    TEE-->>C: Encrypted response
```

--------------------------------

### Public Tenant Map Configuration

Source: https://docs.terminal3.io/t3n/how-t3n-works/z-namespace

Shows the required configuration for a tenant-owned map to be considered public, involving a specific naming convention and visibility setting.

```text
z:<tid>:public:<tail>
visibility = Public
```

--------------------------------

### Verify Contract File Name

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/build-contract

Confirms the existence and details of the compiled WASM component. The file name may differ if your package name contains hyphens, which are converted to underscores.

```bash
ls -lh target/wasm32-wasip2/release/*.wasm
```

--------------------------------

### Register WASM Contract

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/register-contract

Uploads a compiled WASM contract and registers it with a specified tail and version. Ensure you have an authenticated TenantClient, the WASM file path, and your tenant DID. The resulting contract ID is crucial for creating map ACLs.

```typescript
import {
  readFile
} from "fs/promises";

const WASM_PATH = "target/wasm32-wasip2/release/your_contract.wasm";
const CONTRACT_TAIL = "travel/contracts";
const CONTRACT_VERSION = "0.1.0";

const wasmBytes = await readFile(WASM_PATH);

const result = await tenant.contracts.register({
  tail: CONTRACT_TAIL,
  version: CONTRACT_VERSION,
  wasm: wasmBytes,
});

// This numeric ID is required in the next setup step when you create map ACLs.
const contractId = result.contract_id;
const tenantId = tenantDid.slice("did:t3n:".length);
const scriptName = `z:${tenantId}:${CONTRACT_TAIL}`;

console.log(`registered ${scriptName} as contract id ${contractId}`);
```

--------------------------------

### T3N Token Metering Flow

Source: https://docs.terminal3.io/t3n/how-t3n-works/tokens

Illustrates the flow of how a DID's token balance pays for metered contract execution, including compute fuel, host-function calls, and storage.

```text
Your DID balance
  |
  | pays for
  v
Metered contract execution
  - WASM compute fuel
  - host-function calls such as kv.put or cas.write
  - storage deposit and storage rent
  - contract registration when the admin request bills your DID
```

--------------------------------

### WIT Definition for Contract World

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/write-contract

Declares the host interfaces that your contract can import and use. The host links your contract against a matching tenant world.

```wit
package acme:travel-contract@0.1.0;

world contract {
  import t3n:host/kv-store@0.1.0;
  import t3n:host/logging@0.1.0;
  import t3n:host/tenant-context@0.1.0;
  import t3n:host/http-iface@0.1.0;   // synchronous HTTP — call a third-party API
  // PII-safe variant: the host substitutes {{profile.*}} markers from the
  // caller's profile so plaintext PII never enters the contract.
  import t3n:host/http-with-placeholders@0.1.0;

  export t3n:contract/dispatch@0.1.0;
}
```

--------------------------------

### Retrieve Duffel API Key

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/write-contract

This Rust function retrieves the Duffel API key from the host's secrets store. It uses `kv_store::get` to fetch the key and handles potential errors like missing credentials or invalid encoding.

```rust
use crate::bindings::t3n::host::kv_store;

fn duffel_api_key() -> Result<String, ContractError> {
    let bytes = kv_store::get("secrets", "duffel_api_key")? 
        .ok_or(ContractError::CredentialsNotConfigured)?;
    String::from_utf8(bytes)
        .map_err(|_| ContractError::InternalError { detail: "invalid api key encoding".into() })
}
```

--------------------------------

### Canonical Tenant-Owned Namespace Format

Source: https://docs.terminal3.io/t3n/how-t3n-works/z-namespace

Illustrates the structure of a tenant-owned resource name in T3N, which includes the 'z:' prefix, tenant DID suffix, and a tenant-local name.

```text
z:<tid>:<tail>
```

--------------------------------

### Cargo.toml for WASM Component Compilation

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/write-contract

Configures the Rust project to compile into a WASM component. It specifies dependencies like wit-bindgen and serde for efficient compilation and smaller artifact size.

```toml
[package]
name = "your-contract"
version = "0.1.0"
edition = "2021"

# crate-type cdylib is what makes the wasm32-wasip2 target emit a
# WASM *component* (not a bare module). Keep "lib" too so the
# business logic stays unit-testable natively.
[lib]
crate-type = ["cdylib", "lib"]

[dependencies]
# wit-bindgen's macro generates the bindings from wit/world.wit at
# compile time — no separate codegen step.
wit-bindgen = { version = "0.49", default-features = false, features = ["macros", "realloc"] }
serde = { version = "1.0", default-features = false, features = ["derive", "alloc"] }
serde_json = { version = "1.0", default-features = false, features = ["alloc"] }

# Small, self-contained artifact — keeps registration under the size cap.
[profile.release]
opt-level = "s"
lto = true
codegen-units = 1
strip = true

```

--------------------------------

### Seed API Key using map-entry-set

Source: https://docs.terminal3.io/developers/adk/tips/seed-api-key

Use this snippet to write an API key into the secrets map. The key is stored in `process.env.DUFFEL_API_KEY` and is written to the map under the key `duffel_api_key`. This operation bypasses ACLs and is only visible within the TEE.

```typescript
await tenant.executeControl("map-entry-set", {
  map_name: tenant.canonicalName("secrets"),
  key:      "duffel_api_key",
  value:    process.env.DUFFEL_API_KEY!,
});

console.log("API key sealed in z:<tid>:secrets — not visible outside the TEE");
```

--------------------------------

### T3N Multi-Region Architecture Diagram

Source: https://docs.terminal3.io/t3n/how-t3n-works/architecture

Visual representation of the T3N network topology, illustrating two distinct regions with TEE clusters and regional storage. Shows cross-region communication for key sharing and in-region/remote access for storage.

```text
+------------------------------------------------+
| REGION 1                                       |
| (local data processing & residency required)   |
|                                                |
|  +----------------------------------+          |
|  | TEE Cluster 1                    |          |
|  |   [Node 1] <--> [Node 2]         |<--------->|      +-----------------------------------+
|  +----------------+-----------------+          |      | REGION 2                          |
|                   ^                            |      | (no data residency)               |
|                   |                            |      |                                   |
|                   v                            |      |  +-----------------------------+  |
|  +----------------+-----------------+          |      |  | TEE Cluster 2               |  |
|  | Regional Storages                |<--------->|------|  |   [Node 3] <--> [Node 4]    |  |
|  |   [Content Addressable Storage]  |          |      |  +---------------+-------------+  |
|  |   [Regulatory Vault]             |          |      |                  ^                |
|  +----------------------------------+          |      |                  |                |
|                                                |      |                  |                |
+------------------------------------------------+      +-----------------------------------+

Connections
-----------
  Cluster 1  <-->  Cluster 2   (cross-region threshold key sharing)
  Cluster 1  <-->  Regional Storages    (in-region storage)
  Cluster 2  <-->  Regional Storages    (remote access to Region 1 storages)
```

--------------------------------

### Book Offer WASM Contract

Source: https://docs.terminal3.io/developers/adk/get-started/walkthrough/write-contract

This Rust code defines a WASM function to book an offer. It constructs a JSON payload for the booking request, including passenger details and payment information. PII fields are marked with placeholders for privacy.

```rust
fn book_offer_wasm(req: BookOfferReq) -> Result<Booking, String> {
    use serde_json::json;

    let api_key = get_api_key()?;
    let order_body = json!({
        "data": {
            "type": "instant",
            "selected_offers": [req.offer_id],
            "passengers": [{
                "id": req.passenger_id,
                // Resolved from the user's profile (privacy-preserving path):
                "given_name": "{{profile.first_name}}",
                "family_name": "{{profile.last_name}}",
                "born_on": "{{profile.date_of_birth}}",
                "gender": "{{profile.gender}}",
                "email": "{{profile.verified_contacts.email.value}}",
                // Demo-hardcoded (no profile source):
                "title": "mr",
                "passport_number": "X12345678",
                "passport_country_code": "GB",
                "passport_expiry_date": "2030-01-01",
                "phone_number": "+442071234567",
            }],
            "payments": [{
                "type": "balance",
                "amount": req.total_amount,
                "currency": req.total_currency,
            }]
        }
    });
```