feat: discover all protocols + l402.space bridge note

src/commands/discover.ts

@@ -6,7 +6,8 @@ export function registerDiscoverCommand(program: Command) {
   program
     .command("discover")
     .description(
-      "Search 402index.io for paid API services that accept bitcoin/lightning",
+      "Search 402index.io for paid API services (L402, x402, MPP). " +
+        "All are payable in sats with the fetch command.",
     )
     .option("-q, --query <text>", "Search query")
     .option(

src/test/fetch-bridge.test.ts

@@ -0,0 +1,60 @@
+import { describe, test, expect, vi, beforeEach } from "vitest";
+import type { NWCClient } from "@getalby/sdk";
+
+// Mock the underlying protocol handler so we can drive the wrapper's decision
+// logic: lightning-tools already pays L402/MPP/lightning-x402 directly and hands
+// back an unpaid 402 for anything it can't settle over lightning (e.g. USDC-only
+// x402). We assert our wrapper transparently retries those through l402.space.
+const fetch402Lib = vi.fn();
+vi.mock("@getalby/lightning-tools/402", () => ({
+  fetch402: (...args: unknown[]) => fetch402Lib(...args),
+}));
+
+const { fetch402 } = await import("../tools/lightning/fetch.js");
+
+const fakeClient = {} as NWCClient;
+
+beforeEach(() => {
+  fetch402Lib.mockReset();
+});
+
+describe("fetch402 l402.space bridge fallback", () => {
+  test("retries through l402.space when a direct fetch returns 402", async () => {
+    fetch402Lib
+      .mockResolvedValueOnce(new Response("nope", { status: 402 }))
+      .mockResolvedValueOnce(new Response("paid content", { status: 200 }));
+
+    const result = await fetch402(fakeClient, {
+      url: "https://x402.example/api",
+    });
+
+    expect(result.content).toBe("paid content");
+    expect(fetch402Lib).toHaveBeenCalledTimes(2);
+    expect(fetch402Lib.mock.calls[0][0]).toBe("https://x402.example/api");
+    expect(fetch402Lib.mock.calls[1][0]).toBe(
+      "https://l402.space/" + encodeURIComponent("https://x402.example/api"),
+    );
+  });
+
+  test("pays directly without the bridge when the first fetch succeeds", async () => {
+    fetch402Lib.mockResolvedValueOnce(
+      new Response("direct content", { status: 200 }),
+    );
+
+    const result = await fetch402(fakeClient, {
+      url: "https://l402.example/api",
+    });
+
+    expect(result.content).toBe("direct content");
+    expect(fetch402Lib).toHaveBeenCalledTimes(1);
+  });
+
+  test("does not double-bridge a url already pointing at l402.space", async () => {
+    fetch402Lib.mockResolvedValueOnce(new Response("nope", { status: 402 }));
+
+    await expect(
+      fetch402(fakeClient, { url: "https://l402.space/whatever" }),
+    ).rejects.toThrow("non-OK status: 402");
+    expect(fetch402Lib).toHaveBeenCalledTimes(1);
+  });
+});

src/tools/lightning/discover.ts

@@ -15,8 +15,9 @@ export async function discover(params: DiscoverParams) {
   if (params.health) url.searchParams.set("health", params.health);
   if (params.sort) url.searchParams.set("sort", params.sort);
 
-  // Filter to BTC (lightning) services server-side
-  url.searchParams.set("payment_asset", "BTC");
+  // No payment_asset filter: return services across all protocols (L402, x402,
+  // MPP). Non-lightning services (e.g. x402/USDC) can still be paid in sats by
+  // fetching them through the l402.space bridge - see the fetch command.
   url.searchParams.set("limit", String(requestedLimit));
 
   const controller = new AbortController();

src/tools/lightning/fetch.ts

@@ -3,6 +3,19 @@ import { NWCClient } from "@getalby/sdk";
 
 const DEFAULT_MAX_AMOUNT_SATS = 5000;
 
+// Non-lightning paid endpoints (e.g. USDC-only x402) can't be settled from a
+// lightning wallet directly, so lightning-tools hands their 402 back unpaid.
+// The l402.space bridge re-wraps any 402-gated upstream as an L402 (lightning)
+// challenge and settles the upstream cost on our behalf - we transparently
+// retry through it so callers only ever need a lightning balance. Native L402
+// (and lightning-payable x402/MPP) is paid directly and never touches the
+// bridge.
+const L402_SPACE_BRIDGE = "https://l402.space/";
+
+function bridgeUrl(url: string): string {
+  return `${L402_SPACE_BRIDGE}${encodeURIComponent(url)}`;
+}
+
 export interface Fetch402Params {
   url: string;
   method?: string;
@@ -13,27 +26,40 @@ export interface Fetch402Params {
 
 export async function fetch402(client: NWCClient, params: Fetch402Params) {
   const method = params.method?.toUpperCase();
-  const requestOptions: RequestInit = {
-    method,
-  };
 
-  if (method && method !== "GET" && method !== "HEAD") {
-    requestOptions.body = params.body;
-    requestOptions.headers = {
-      "Content-Type": "application/json",
-      ...params.headers,
-    };
-  } else if (params.headers) {
-    requestOptions.headers = params.headers;
-  }
+  // fetch402Lib mutates the RequestInit it's given (headers, cache, mode), so
+  // build a fresh one per attempt to keep the bridge retry clean.
+  const buildRequestOptions = (): RequestInit => {
+    const requestOptions: RequestInit = { method };
+    if (method && method !== "GET" && method !== "HEAD") {
+      requestOptions.body = params.body;
+      requestOptions.headers = {
+        "Content-Type": "application/json",
+        ...params.headers,
+      };
+    } else if (params.headers) {
+      requestOptions.headers = params.headers;
+    }
+    return requestOptions;
+  };
 
   const maxAmountSats = params.maxAmountSats ?? DEFAULT_MAX_AMOUNT_SATS;
 
-  const result = await fetch402Lib(params.url, requestOptions, {
+  let result = await fetch402Lib(params.url, buildRequestOptions(), {
     wallet: client,
     maxAmount: maxAmountSats,
   });
 
+  // A 402 here means lightning-tools couldn't satisfy the challenge over
+  // lightning and handed the response back. Retry once through the l402.space
+  // bridge, which converts it to an L402 lightning challenge we can pay.
+  if (result.status === 402 && !params.url.startsWith(L402_SPACE_BRIDGE)) {
+    result = await fetch402Lib(bridgeUrl(params.url), buildRequestOptions(), {
+      wallet: client,
+      maxAmount: maxAmountSats,
+    });
+  }
+
   const responseContent = await result.text();
   if (!result.ok) {
     throw new Error(