fix(x402-evm): inject EIP-712 USDC domain (verified on Base mainnet)

README.md

@@ -98,9 +98,9 @@ Current version: `0.3.0-beta.1`.
 | SQLite / D1 ledger           | Local and single-process paths                                  |
 | Stripe test mode             | Validated with configured test credentials                      |
 | Stripe production            | Beta; validate your webhook and deployment path                 |
-| x402 (EVM)                   | Experimental                                                    |
+| x402 (EVM)                   | Beta; EIP-712 USDC domain auto-injected, verified on Base mainnet (gasless via facilitator) |
 | x402 (Solana / SVM)          | Experimental; SVM "exact" scheme, facilitator verify/settle ([notes](examples/x402-solana-recovery/NOTES.md)) |
-| x402 mainnet                 | Not tested                                                      |
+| x402 mainnet                 | Smoke-tested with small live settles: EVM (Base) and Solana     |
 | MPP                          | Mocked / spec-path unless verified with real `mppx` integration |
 | Multi-instance production    | Requires durable idempotency; future work                       |
 

landing/index.html

@@ -421,7 +421,7 @@ <h2>Status</h2>
               <tr><td>SQLite / D1 ledger</td><td>Local and single-process paths</td></tr>
               <tr><td>Stripe test mode</td><td>Validated with configured test credentials</td></tr>
               <tr><td>Stripe production</td><td>Beta; validate your webhook and deployment path</td></tr>
-              <tr><td>x402 — EVM (Base, Polygon, Arbitrum, Optimism, Ethereum)</td><td>Experimental; mainnet not tested</td></tr>
+              <tr><td>x402 — EVM (Base, Polygon, Arbitrum, Optimism, Ethereum)</td><td>Beta; EIP-712 USDC domain auto-injected, verified on Base mainnet (gasless)</td></tr>
               <tr><td>x402 — Solana / SVM</td><td>Experimental; verified on devnet (gasless via x402 facilitators), mainnet not tested</td></tr>
               <tr><td>MPP</td><td>Mocked / spec-path unless verified with real mppx integration</td></tr>
             </tbody>

package.json

@@ -39,7 +39,7 @@
     "scenario:x402-testnet:challenge": "npm run build && node examples/x402-testnet-recovery/challenge.mjs",
     "scenario:x402-testnet:sign": "npm run build && node examples/x402-testnet-recovery/challenge.mjs | node examples/x402-testnet-recovery/sign-payload.mjs",
     "scenario:x402-testnet": "npm run build && node integrations/x402-testnet/scenario.mjs",
-    "test": "npm run build && node --test --test-force-exit src/__tests__/paidTool.test.mjs src/__tests__/mcp-adapter.test.mjs src/__tests__/stripe.test.mjs src/__tests__/webhook-handler.test.mjs src/__tests__/db-ledger.test.mjs src/__tests__/rail-adapter.test.mjs src/__tests__/x402-solana-rail.test.mjs src/__tests__/x402-solana-sign.test.mjs src/__tests__/policy.test.mjs src/__tests__/protocol-compliance.test.mjs src/__tests__/idempotency.test.mjs src/__tests__/concurrency.test.mjs src/__tests__/db-idempotency.integration.test.mjs src/__tests__/trace.test.mjs src/__tests__/firecrawl-integration.test.mjs src/__tests__/local-first.test.mjs",
+    "test": "npm run build && node --test --test-force-exit src/__tests__/paidTool.test.mjs src/__tests__/mcp-adapter.test.mjs src/__tests__/stripe.test.mjs src/__tests__/webhook-handler.test.mjs src/__tests__/db-ledger.test.mjs src/__tests__/rail-adapter.test.mjs src/__tests__/x402-evm-rail.test.mjs src/__tests__/x402-solana-rail.test.mjs src/__tests__/x402-solana-sign.test.mjs src/__tests__/policy.test.mjs src/__tests__/protocol-compliance.test.mjs src/__tests__/idempotency.test.mjs src/__tests__/concurrency.test.mjs src/__tests__/db-idempotency.integration.test.mjs src/__tests__/trace.test.mjs src/__tests__/firecrawl-integration.test.mjs src/__tests__/local-first.test.mjs",
     "prepublishOnly": "npm run typecheck && npm test"
   },
   "keywords": [

src/__tests__/x402-evm-rail.test.mjs

@@ -0,0 +1,109 @@
+/**
+ * x402 EVM Rail Adapter — EIP-712 domain injection.
+ *
+ * The EVM "exact" scheme (EIP-3009) requires the token's EIP-712 domain
+ * (name + version) in PaymentRequirements.extra, or the facilitator rejects
+ * verify with `invalid_exact_evm_missing_eip712_domain`. These tests assert the
+ * rail injects it for known USDC networks, honours an explicit override, and
+ * forwards it to the facilitator — all offline (fetch stubbed).
+ *
+ * Run: node --test src/__tests__/x402-evm-rail.test.mjs
+ */
+
+import { describe, it, beforeEach, afterEach } from "node:test";
+import assert from "node:assert/strict";
+import {
+  X402RailAdapter,
+  EVM_USDC_ADDRESSES,
+} from "../../dist/rail-adapters/x402-rail.js";
+
+const BASE = "eip155:8453";
+const BASE_SEPOLIA = "eip155:84532";
+const PAY_TO = "0x179516864079FA14a0a718cF767cCDc2483324b6";
+const FACILITATOR = "https://facilitator.example.test";
+
+const PARAMS = {
+  callerId: "0xCaller",
+  amount: 0.001,
+  currency: "usd",
+  toolName: "evm_tool",
+  publisherKey: "tg_evm",
+};
+
+function makeAdapter(overrides = {}) {
+  return new X402RailAdapter({
+    payTo: PAY_TO,
+    network: { kind: "evm", caip2: BASE },
+    facilitatorUrl: FACILITATOR,
+    x402Version: 2,
+    ...overrides,
+  });
+}
+
+describe("x402 EVM — EIP-712 domain in challenge", () => {
+  it("auto-injects USD Coin v2 for Base mainnet USDC", async () => {
+    const action = await makeAdapter().createChallenge(PARAMS);
+    const req = action.x402PaymentRequired.accepts[0];
+    assert.equal(req.asset, EVM_USDC_ADDRESSES[BASE]);
+    assert.equal(req.extra.name, "USD Coin");
+    assert.equal(req.extra.version, "2");
+  });
+
+  it("uses USDC v2 for Base Sepolia testnet", async () => {
+    const action = await makeAdapter({
+      network: { kind: "evm", caip2: BASE_SEPOLIA },
+    }).createChallenge(PARAMS);
+    const req = action.x402PaymentRequired.accepts[0];
+    assert.equal(req.extra.name, "USDC");
+    assert.equal(req.extra.version, "2");
+  });
+
+  it("honours an explicit eip712Domain override (custom token)", async () => {
+    const action = await makeAdapter({
+      network: { kind: "evm", caip2: "eip155:99999", asset: "0xabc" },
+      eip712Domain: { name: "MyToken", version: "1" },
+    }).createChallenge(PARAMS);
+    const req = action.x402PaymentRequired.accepts[0];
+    assert.equal(req.extra.name, "MyToken");
+    assert.equal(req.extra.version, "1");
+  });
+
+  it("does not attach feePayer for EVM", async () => {
+    const action = await makeAdapter().createChallenge(PARAMS);
+    assert.equal(
+      action.x402PaymentRequired.accepts[0].extra.feePayer,
+      undefined,
+    );
+  });
+});
+
+describe("x402 EVM — domain forwarded to the facilitator", () => {
+  const realFetch = globalThis.fetch;
+  let captured;
+
+  beforeEach(() => {
+    captured = [];
+    globalThis.fetch = async (url, init) => {
+      captured.push({ url: String(url), body: JSON.parse(init.body) });
+      return { ok: true, async json() { return { isValid: true, payer: PAY_TO }; } };
+    };
+  });
+  afterEach(() => {
+    globalThis.fetch = realFetch;
+  });
+
+  it("verify sends extra.name/version in paymentRequirements", async () => {
+    const adapter = makeAdapter();
+    const action = await adapter.createChallenge(PARAMS);
+    const proof = { rail: "x402", x402PaymentPayload: { x402Version: 2 } };
+
+    const result = await adapter.verifyPayment(proof, {
+      actionId: action.actionId,
+    });
+    assert.ok(result?.verified);
+    const sent = captured.find((c) => c.url.endsWith("/verify"));
+    assert.ok(sent, "verify was called");
+    assert.equal(sent.body.paymentRequirements.extra.name, "USD Coin");
+    assert.equal(sent.body.paymentRequirements.extra.version, "2");
+  });
+});

src/index.ts

@@ -58,6 +58,7 @@ export {
   MppRailAdapter,
   X402RailAdapter,
   EVM_USDC_ADDRESSES,
+  EVM_USDC_EIP712_DOMAINS,
   SOLANA_USDC_ADDRESSES,
 } from "./rail-adapters/index.js";
 export type {

src/rail-adapters/index.ts

@@ -7,6 +7,7 @@ export type { MppRailConfig } from "./mpp-rail.js";
 export {
   X402RailAdapter,
   EVM_USDC_ADDRESSES,
+  EVM_USDC_EIP712_DOMAINS,
   SOLANA_USDC_ADDRESSES,
 } from "./x402-rail.js";
 export type { X402RailConfig } from "./x402-rail.js";

src/rail-adapters/x402-rail.ts

@@ -51,6 +51,15 @@ export interface X402RailConfig {
    */
   feePayer?: string;
 
+  /**
+   * EIP-712 token domain (name + version) for EVM payments, surfaced to the
+   * facilitator via `PaymentRequirements.extra` so it can verify the EIP-3009
+   * signature. Auto-detected from `EVM_USDC_EIP712_DOMAINS` for known USDC
+   * networks; set this only for a non-USDC asset or a custom token. Ignored for
+   * Solana.
+   */
+  eip712Domain?: { name: string; version: string };
+
   /**
    * Facilitator URL for payment verification and settlement.
    *
@@ -85,6 +94,25 @@ export const EVM_USDC_ADDRESSES: Record<string, `0x${string}`> = {
   "eip155:10": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85", // Optimism
 };
 
+/**
+ * EIP-712 domain (name + version) for USDC on each EVM network. The facilitator
+ * needs this in `PaymentRequirements.extra` to verify the EIP-3009 signature —
+ * without it, verify fails with `invalid_exact_evm_missing_eip712_domain`.
+ * Circle's USDC uses name "USD Coin" v2 on mainnets; Base Sepolia testnet USDC
+ * uses "USDC" v2.
+ */
+export const EVM_USDC_EIP712_DOMAINS: Record<
+  string,
+  { name: string; version: string }
+> = {
+  "eip155:8453": { name: "USD Coin", version: "2" }, // Base mainnet
+  "eip155:84532": { name: "USDC", version: "2" }, // Base Sepolia
+  "eip155:1": { name: "USD Coin", version: "2" }, // Ethereum mainnet
+  "eip155:137": { name: "USD Coin", version: "2" }, // Polygon
+  "eip155:42161": { name: "USD Coin", version: "2" }, // Arbitrum
+  "eip155:10": { name: "USD Coin", version: "2" }, // Optimism
+};
+
 /** USDC mint addresses for Solana networks (SPL Token) */
 export const SOLANA_USDC_ADDRESSES: Record<string, string> = {
   "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp":
@@ -156,6 +184,19 @@ export class X402RailAdapter implements RailAdapter {
       extra.feePayer = this.config.feePayer;
     }
 
+    // EVM "exact" (EIP-3009) requires the token's EIP-712 domain so the
+    // facilitator can verify the authorization signature. Auto-detect for known
+    // USDC networks; otherwise honour an explicitly configured domain.
+    if (!this.isSolana) {
+      const domain =
+        this.config.eip712Domain ??
+        EVM_USDC_EIP712_DOMAINS[this.config.network.caip2];
+      if (domain) {
+        extra.name = domain.name;
+        extra.version = domain.version;
+      }
+    }
+
     const paymentRequirement: X402PaymentRequirement = {
       scheme: this.config.scheme ?? "exact",
       network: this.config.network.caip2,