run402-mcp
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MCP server for Run402 — full-stack backend infrastructure for AI agents: Postgres, auth, storage, serverless functions and atomic deploys. Paid with x402/MPP. Includes $0.03 image generation.
384 lines • 17.1 kB
JavaScript
/**
* Minimal NIP-47 (Nostr Wallet Connect) client for the agent's Lightning
* wallet: the budgeted sub-wallet Run402 minted on its Hub (`run402 init
* lightning`). One standing relay WebSocket per pairing, NIP-44 v2 only,
* requests matched to replies by event id. The pairing URI carries the
* client's secret key: this module never logs or returns it.
*
* Node ≥ 22 (global `WebSocket`).
*/
import { createCipheriv, createHash, randomBytes, timingSafeEqual } from "node:crypto";
import { schnorr, secp256k1 } from "@noble/curves/secp256k1.js";
import { expand, extract } from "@noble/hashes/hkdf.js";
import { hmac } from "@noble/hashes/hmac.js";
import { sha256 } from "@noble/hashes/sha2.js";
export const NWC_REQUEST_KIND = 23194;
export const NWC_RESPONSE_KIND = 23195;
const DEFAULT_TIMEOUT_MS = 30_000;
const RELAY_HANDSHAKE_TIMEOUT_MS = 10_000;
// Short: a one-shot CLI process must not linger on an open relay socket after its
// last request; reconnecting costs one handshake and long-lived callers keep
// the socket warm by talking.
const RELAY_IDLE_CLOSE_MS = 1_500;
export class NwcError extends Error {
code;
constructor(code, message) {
super(message);
this.code = code;
this.name = "NwcError";
}
}
export function parseNwcUri(uri) {
let url;
try {
url = new URL(uri.replace(/^nostr\+walletconnect:\/\//i, "nostr+walletconnect://"));
}
catch {
throw new NwcError("BAD_URI", "pairing URI is not a URL");
}
if (!/^nostr\+walletconnect:$/i.test(url.protocol))
throw new NwcError("BAD_URI", "pairing URI must use nostr+walletconnect://");
const walletPubkey = (url.host || url.pathname.replace(/^\/+/, "")).toLowerCase();
const relayUrl = url.searchParams.get("relay") ?? "";
const secretHex = (url.searchParams.get("secret") ?? "").toLowerCase();
if (!/^[0-9a-f]{64}$/.test(walletPubkey))
throw new NwcError("BAD_URI", "pairing URI lacks the wallet pubkey");
if (!/^wss?:\/\//.test(relayUrl))
throw new NwcError("BAD_URI", "pairing URI lacks a relay");
if (!/^[0-9a-f]{64}$/.test(secretHex))
throw new NwcError("BAD_URI", "pairing URI lacks the connection secret");
const clientPubkey = Buffer.from(schnorr.getPublicKey(Buffer.from(secretHex, "hex"))).toString("hex");
return { walletPubkey, relayUrl, secretHex, clientPubkey };
}
// --- NIP-44 v2 ------------------------------------------------------------
function calcPaddedLen(unpaddedLen) {
if (unpaddedLen <= 32)
return 32;
const nextPower = 1 << (Math.floor(Math.log2(unpaddedLen - 1)) + 1);
const chunk = nextPower <= 256 ? 32 : nextPower / 8;
return chunk * (Math.floor((unpaddedLen - 1) / chunk) + 1);
}
export function nip44ConversationKey(secretHex, peerPubkeyHex) {
const shared = secp256k1.getSharedSecret(Buffer.from(secretHex, "hex"), Buffer.from("02" + peerPubkeyHex, "hex"), true);
return extract(sha256, shared.subarray(1, 33), new TextEncoder().encode("nip44-v2"));
}
function messageKeys(conversation, nonce) {
const keys = expand(sha256, conversation, nonce, 76);
return { chacha: keys.subarray(0, 32), chachaNonce: keys.subarray(32, 44), hmacKey: keys.subarray(44, 76) };
}
function chacha20(key, nonce12, data) {
const cipher = createCipheriv("chacha20", Buffer.from(key), Buffer.concat([Buffer.alloc(4), Buffer.from(nonce12)]));
return Buffer.concat([cipher.update(Buffer.from(data)), cipher.final()]);
}
export function nip44Encrypt(conversation, plaintext, nonce = randomBytes(32)) {
const bytes = new TextEncoder().encode(plaintext);
if (bytes.length < 1 || bytes.length > 65_535)
throw new NwcError("BAD_PAYLOAD", "plaintext length out of range");
const padded = new Uint8Array(2 + calcPaddedLen(bytes.length));
padded[0] = bytes.length >> 8;
padded[1] = bytes.length & 0xff;
padded.set(bytes, 2);
const keys = messageKeys(conversation, nonce);
const ciphertext = chacha20(keys.chacha, keys.chachaNonce, padded);
const mac = hmac(sha256, keys.hmacKey, Buffer.concat([Buffer.from(nonce), Buffer.from(ciphertext)]));
return Buffer.concat([Buffer.from([2]), Buffer.from(nonce), Buffer.from(ciphertext), Buffer.from(mac)]).toString("base64");
}
export function nip44Decrypt(conversation, payload) {
if (payload.startsWith("#"))
throw new NwcError("UNSUPPORTED_ENCRYPTION", "unknown NIP-44 version");
const data = Buffer.from(payload, "base64");
if (data.length < 99 || data[0] !== 2)
throw new NwcError("BAD_PAYLOAD", "NIP-44 payload is malformed");
const nonce = data.subarray(1, 33);
const ciphertext = data.subarray(33, data.length - 32);
const mac = data.subarray(data.length - 32);
const keys = messageKeys(conversation, nonce);
const expected = Buffer.from(hmac(sha256, keys.hmacKey, Buffer.concat([nonce, ciphertext])));
if (!timingSafeEqual(expected, mac))
throw new NwcError("BAD_PAYLOAD", "NIP-44 MAC mismatch");
const padded = chacha20(keys.chacha, keys.chachaNonce, ciphertext);
const length = (padded[0] << 8) | padded[1];
return new TextDecoder().decode(padded.subarray(2, 2 + length));
}
export function signNwcEvent(secretHex, kind, tags, content) {
const pubkey = Buffer.from(schnorr.getPublicKey(Buffer.from(secretHex, "hex"))).toString("hex");
const created_at = Math.floor(Date.now() / 1000);
const id = createHash("sha256").update(JSON.stringify([0, pubkey, created_at, kind, tags, content])).digest("hex");
const sig = Buffer.from(schnorr.sign(Buffer.from(id, "hex"), Buffer.from(secretHex, "hex"))).toString("hex");
return { id, pubkey, created_at, kind, tags, content, sig };
}
function verifyEvent(event) {
try {
const id = createHash("sha256").update(JSON.stringify([0, event.pubkey, event.created_at, event.kind, event.tags, event.content])).digest("hex");
if (id !== event.id)
return false;
return schnorr.verify(Buffer.from(event.sig, "hex"), Buffer.from(id, "hex"), Buffer.from(event.pubkey, "hex"));
}
catch {
return false;
}
}
class Relay {
url;
clientPubkey;
socket = null;
opening = null;
pending = new Map();
idle = null;
subId = randomBytes(8).toString("hex");
constructor(url, clientPubkey) {
this.url = url;
this.clientPubkey = clientPubkey;
}
async send(request, timeoutMs) {
const socket = await this.connected(timeoutMs);
return new Promise((resolve, reject) => {
const timer = setTimeout(() => {
this.pending.delete(request.id);
this.armIdle();
reject(new NwcError("TIMEOUT", "no wallet response within the timeout"));
}, timeoutMs);
this.pending.set(request.id, { resolve, reject, timer });
if (this.idle) {
clearTimeout(this.idle);
this.idle = null;
}
try {
socket.send(JSON.stringify(["EVENT", request]));
}
catch (error) {
this.settle(request.id, new NwcError("RELAY_CLOSED", error instanceof Error ? error.message : "send failed"));
}
});
}
close() {
if (this.idle) {
clearTimeout(this.idle);
this.idle = null;
}
const socket = this.socket;
this.socket = null;
this.opening = null;
if (socket) {
try {
socket.close();
}
catch { /* closed */ }
}
for (const id of [...this.pending.keys()])
this.settle(id, new NwcError("RELAY_CLOSED", "relay connection closed"));
}
armIdle() {
if (this.idle)
clearTimeout(this.idle);
this.idle = setTimeout(() => this.close(), RELAY_IDLE_CLOSE_MS);
this.idle.unref?.();
}
settle(id, error, event) {
const entry = this.pending.get(id);
if (!entry)
return;
this.pending.delete(id);
clearTimeout(entry.timer);
if (error)
entry.reject(error);
else
entry.resolve(event);
if (this.pending.size === 0)
this.armIdle();
}
connected(timeoutMs) {
if (this.socket && this.socket.readyState === WebSocket.OPEN)
return Promise.resolve(this.socket);
if (this.opening)
return this.opening;
this.opening = new Promise((resolve, reject) => {
let socket;
try {
socket = new WebSocket(this.url);
}
catch (error) {
this.opening = null;
reject(new NwcError("RELAY_UNREACHABLE", error instanceof Error ? error.message : "cannot open relay"));
return;
}
let opened = false;
const handshake = setTimeout(() => {
if (!opened) {
this.opening = null;
try {
socket.close();
}
catch { /* */ }
reject(new NwcError("RELAY_UNREACHABLE", "relay handshake timed out"));
}
}, Math.min(timeoutMs, RELAY_HANDSHAKE_TIMEOUT_MS));
socket.addEventListener("open", () => {
opened = true;
clearTimeout(handshake);
this.socket = socket;
this.opening = null;
socket.send(JSON.stringify(["REQ", this.subId, { kinds: [NWC_RESPONSE_KIND], "#p": [this.clientPubkey], since: Math.floor(Date.now() / 1000) - 60 }]));
resolve(socket);
});
socket.addEventListener("message", (message) => this.onMessage(String(message.data)));
socket.addEventListener("error", () => {
if (!opened) {
clearTimeout(handshake);
this.opening = null;
reject(new NwcError("RELAY_UNREACHABLE", "relay connection failed"));
}
});
socket.addEventListener("close", () => {
if (this.socket === socket)
this.socket = null;
if (!opened) {
clearTimeout(handshake);
this.opening = null;
reject(new NwcError("RELAY_UNREACHABLE", "relay closed during handshake"));
}
for (const id of [...this.pending.keys()])
this.settle(id, new NwcError("RELAY_CLOSED", "relay closed the connection"));
});
});
return this.opening;
}
onMessage(raw) {
let message;
try {
message = JSON.parse(raw);
}
catch {
return;
}
if (!Array.isArray(message))
return;
if (message[0] === "EVENT" && message[1] === this.subId && message[2] && typeof message[2] === "object") {
const event = message[2];
if (event.kind !== NWC_RESPONSE_KIND || !Array.isArray(event.tags))
return;
const ref = event.tags.find((tag) => tag[0] === "e" && typeof tag[1] === "string");
if (ref?.[1])
this.settle(ref[1], null, event);
return;
}
if (message[0] === "OK" && typeof message[1] === "string" && message[2] === false) {
this.settle(message[1], new NwcError("RELAY_REJECTED", typeof message[3] === "string" ? message[3] : "relay rejected the request"));
}
}
}
const relays = new Map();
function relayFor(connection) {
const key = `${connection.relayUrl}|${connection.clientPubkey}`;
let relay = relays.get(key);
if (!relay) {
relay = new Relay(connection.relayUrl, connection.clientPubkey);
relays.set(key, relay);
}
return relay;
}
/** Closes every standing relay connection (process exit, tests). */
export function closeNwcConnections() {
for (const relay of relays.values())
relay.close();
relays.clear();
}
/**
* One NIP-47 call. Throws `NwcError` with the wallet's error code
* (`INSUFFICIENT_BALANCE`, `QUOTA_EXCEEDED`, `NOT_FOUND`, `UNAUTHORIZED`, …)
* or a transport code (`TIMEOUT`, `RELAY_UNREACHABLE`, `RELAY_REJECTED`, `RELAY_CLOSED`, `BAD_RESPONSE`).
*/
export async function nwcRequest(connection, method, params, options = {}) {
const timeoutMs = options.timeoutMs ?? DEFAULT_TIMEOUT_MS;
const transport = options.transport ?? ((c, request, t) => relayFor(c).send(request, t));
const key = nip44ConversationKey(connection.secretHex, connection.walletPubkey);
const content = nip44Encrypt(key, JSON.stringify({ method, params }));
const request = signNwcEvent(connection.secretHex, NWC_REQUEST_KIND, [["p", connection.walletPubkey], ["encryption", "nip44_v2"]], content);
const response = await transport(connection, request, timeoutMs);
if (response.pubkey !== connection.walletPubkey || !verifyEvent(response)) {
throw new NwcError("BAD_RESPONSE", "response is not signed by the wallet service");
}
let body;
try {
body = JSON.parse(nip44Decrypt(key, response.content));
}
catch (error) {
throw error instanceof NwcError ? error : new NwcError("BAD_RESPONSE", "response payload is not JSON");
}
if (body.error && typeof body.error === "object") {
throw new NwcError(typeof body.error.code === "string" ? body.error.code : "OTHER", typeof body.error.message === "string" ? body.error.message : "wallet error");
}
if (body.result_type !== undefined && body.result_type !== method)
throw new NwcError("BAD_RESPONSE", `unexpected result_type ${String(body.result_type)}`);
if (body.result === undefined || body.result === null)
throw new NwcError("BAD_RESPONSE", "response carries no result");
return body.result;
}
/** The agent-side wallet verbs the Lightning rail needs. Amounts are in sats. */
export class NwcWallet {
options;
connection;
constructor(pairingUri, options = {}) {
this.options = options;
this.connection = parseNwcUri(pairingUri);
}
call(method, params) {
return nwcRequest(this.connection, method, params, this.options);
}
/** The node behind the pairing: its network name, pubkey, and permitted methods. */
async getInfo() {
const result = await this.call("get_info", {});
return {
network: typeof result.network === "string" ? result.network.toLowerCase() : null,
pubkey: typeof result.pubkey === "string" ? result.pubkey.toLowerCase() : null,
methods: Array.isArray(result.methods) ? result.methods.map(String) : [],
};
}
async getBalanceSats() {
const result = await this.call("get_balance", {});
return Math.floor(Number(result.balance ?? 0) / 1_000);
}
/** Remaining budget in sats, or null when the wallet has no budget. */
async getBudgetSats() {
let result;
try {
result = await this.call("get_budget", {});
}
catch (error) {
if (error instanceof NwcError && (error.code === "NOT_IMPLEMENTED" || error.code === "RESTRICTED"))
return null;
throw error;
}
const total = result["total_budget"];
if (total === undefined || total === null)
return null;
const renews = result["renews_at"];
return {
usedSats: Math.floor(Number(result["used_budget"] ?? 0) / 1_000),
totalSats: Math.floor(Number(total) / 1_000),
renewsAtSeconds: typeof renews === "number" ? renews : null,
};
}
/** Pays a BOLT11 invoice; returns the preimage (hex) the wallet reports. */
async payInvoice(bolt11) {
const result = await this.call("pay_invoice", { invoice: bolt11 });
const preimage = typeof result.preimage === "string" ? result.preimage.toLowerCase() : "";
if (!/^[0-9a-f]{64}$/.test(preimage))
throw new NwcError("BAD_RESPONSE", "pay_invoice returned no preimage");
return { preimage, feesPaidMsat: typeof result.fees_paid === "number" ? result.fees_paid : null };
}
/** Looks an invoice up by payment hash; a settled outgoing payment carries its preimage. */
async lookupInvoice(paymentHash) {
try {
const result = await this.call("lookup_invoice", { payment_hash: paymentHash });
const preimage = typeof result.preimage === "string" && /^[0-9a-f]{64}$/i.test(result.preimage) ? result.preimage.toLowerCase() : null;
return { state: typeof result.state === "string" ? result.state.toLowerCase() : null, preimage };
}
catch (error) {
if (error instanceof NwcError && error.code === "NOT_FOUND")
return null;
throw error;
}
}
}
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