diff --git a/packages/ack-pay/src/errors.ts b/packages/ack-pay/src/errors.ts
index 3765649..5397cce 100644
--- a/packages/ack-pay/src/errors.ts
+++ b/packages/ack-pay/src/errors.ts
@@ -1,6 +1,6 @@
 export class InvalidPaymentRequestTokenError extends Error {
-  constructor(message = "Invalid payment request token") {
-    super(message)
+  constructor(message = "Invalid payment request token", options?: ErrorOptions) {
+    super(message, options)
     this.name = "InvalidPaymentRequestTokenError"
   }
 }
diff --git a/packages/ack-pay/src/verify-payment-request-token.test.ts b/packages/ack-pay/src/verify-payment-request-token.test.ts
index 935a1de..f42dac5 100644
--- a/packages/ack-pay/src/verify-payment-request-token.test.ts
+++ b/packages/ack-pay/src/verify-payment-request-token.test.ts
@@ -15,6 +15,7 @@ import { generateKeypair, type Keypair } from "@agentcommercekit/keys"
 import { beforeEach, describe, expect, it } from "vitest"
 
 import { createSignedPaymentRequest } from "./create-signed-payment-request"
+import { InvalidPaymentRequestTokenError } from "./errors"
 import type { PaymentRequestInit } from "./payment-request"
 import { verifyPaymentRequestToken } from "./verify-payment-request-token"
 
@@ -78,18 +79,21 @@ describe("verifyPaymentRequestToken", () => {
     expect(result.parsed.issuer).toEqual(issuerDid)
   })
 
-  it("throws for invalid JWT format", async () => {
+  it("throws for invalid JWT format with original error as cause", async () => {
     const resolver = getDidResolver()
     resolver.addToCache(issuerDid, issuerDidDocument)
 
-    await expect(
-      verifyPaymentRequestToken("invalid.jwt.token", {
-        resolver,
-      }),
-    ).rejects.toThrow("Invalid payment request token")
+    const error = await verifyPaymentRequestToken("invalid.jwt.token", {
+      resolver,
+    }).catch((e) => e)
+
+    expect(error).toBeInstanceOf(InvalidPaymentRequestTokenError)
+    expect(error.message).toBe("Invalid payment request token")
+    expect(error.cause).toBeDefined()
+    expect(error.cause).toBeInstanceOf(Error)
   })
 
-  it("throws for expired JWT", async () => {
+  it("throws for expired JWT with original error as cause", async () => {
     // Create a JWT with an expiration date in the past
     const expiredPayload = {
       ...paymentRequest,
@@ -111,11 +115,13 @@ describe("verifyPaymentRequestToken", () => {
     const resolver = getDidResolver()
     resolver.addToCache(issuerDid, issuerDidDocument)
 
-    await expect(
-      verifyPaymentRequestToken(expiredToken, {
-        resolver,
-      }),
-    ).rejects.toThrow("Invalid payment request token")
+    const error = await verifyPaymentRequestToken(expiredToken, {
+      resolver,
+    }).catch((e) => e)
+
+    expect(error).toBeInstanceOf(InvalidPaymentRequestTokenError)
+    expect(error.cause).toBeDefined()
+    expect(error.cause).toBeInstanceOf(Error)
   })
 
   it("allows expired JWT when expiry verification is disabled", async () => {
@@ -150,7 +156,7 @@ describe("verifyPaymentRequestToken", () => {
     expect(result.parsed.issuer).toEqual(issuerDid)
   })
 
-  it("throws for JWT with invalid signature", async () => {
+  it("throws for JWT with invalid signature with original error as cause", async () => {
     const body = await createSignedPaymentRequest(paymentRequest, {
       issuer: issuerDid,
       signer,
@@ -168,14 +174,16 @@ describe("verifyPaymentRequestToken", () => {
       }),
     )
 
-    await expect(
-      verifyPaymentRequestToken(body.paymentRequestToken, {
-        resolver,
-      }),
-    ).rejects.toThrow("Invalid payment request token")
+    const error = await verifyPaymentRequestToken(body.paymentRequestToken, {
+      resolver,
+    }).catch((e) => e)
+
+    expect(error).toBeInstanceOf(InvalidPaymentRequestTokenError)
+    expect(error.cause).toBeDefined()
+    expect(error.cause).toBeInstanceOf(Error)
   })
 
-  it("throws for a JWT that does not contain a payment config", async () => {
+  it("throws for a JWT that does not contain a payment config without cause", async () => {
     // Create a JWT with valid format but missing payment config
     const invalidToken = await createJwt(
       { sub: "test-payment-request-id" },
@@ -188,10 +196,14 @@ describe("verifyPaymentRequestToken", () => {
     const resolver = getDidResolver()
     resolver.addToCache(issuerDid, issuerDidDocument)
 
-    await expect(
-      verifyPaymentRequestToken(invalidToken, {
-        resolver,
-      }),
-    ).rejects.toThrow("Payment Request token is not a valid PaymentRequest")
+    const error = await verifyPaymentRequestToken(invalidToken, {
+      resolver,
+    }).catch((e) => e)
+
+    expect(error).toBeInstanceOf(InvalidPaymentRequestTokenError)
+    expect(error.message).toBe(
+      "Payment Request token is not a valid PaymentRequest",
+    )
+    expect(error.cause).toBeUndefined()
   })
 })
diff --git a/packages/ack-pay/src/verify-payment-request-token.ts b/packages/ack-pay/src/verify-payment-request-token.ts
index c951390..d1c3d28 100644
--- a/packages/ack-pay/src/verify-payment-request-token.ts
+++ b/packages/ack-pay/src/verify-payment-request-token.ts
@@ -43,8 +43,8 @@ export async function verifyPaymentRequestToken(
         exp: options.verifyExpiry ?? true,
       },
     })
-  } catch (_err) {
-    throw new InvalidPaymentRequestTokenError()
+  } catch (err) {
+    throw new InvalidPaymentRequestTokenError(undefined, { cause: err })
   }
 
   const { success, output } = v.safeParse(