diff --git a/.cspell/custom-words.txt b/.cspell/custom-words.txt
index ce73c361..eb298395 100644
--- a/.cspell/custom-words.txt
+++ b/.cspell/custom-words.txt
@@ -185,3 +185,9 @@ XVCJ
 Yapily
 Zalopay
 Zalora
+codegen
+datamodel
+pisp
+PISP
+pyca
+SECP
diff --git a/code/sdk/python/ap2/sdk/generated/payment_receipt.py b/code/sdk/python/ap2/sdk/generated/payment_receipt.py
index 5b381535..2bb7e647 100644
--- a/code/sdk/python/ap2/sdk/generated/payment_receipt.py
+++ b/code/sdk/python/ap2/sdk/generated/payment_receipt.py
@@ -50,6 +50,10 @@ class PaymentReceiptSuccess(BaseModel):
         ...,
         description='A unique identifier for the transaction confirmation at the network. Present only if status is Success.',
     )
+    rail_confirmation_verified: bool | None = Field(
+        default=None,
+        description='Meaningful only if status is Success. True only if the issuer independently confirmed psp_confirmation_id and network_confirmation_id against the actual payment rail (PSP/network) before issuing this receipt, rather than merely generating them. Absent or false means these confirmation IDs are self-declared by the issuer and MUST NOT be treated as evidence that payment-rail settlement occurred: presence of a confirmation ID proves the issuer asserted a claim, not that the claim was checked.',
+    )
 
 
 class PaymentReceiptError(BaseModel):
@@ -82,6 +86,10 @@ class PaymentReceiptError(BaseModel):
         default=None,
         description='A unique identifier for the transaction confirmation at the network. Present only if status is Success.',
     )
+    rail_confirmation_verified: bool | None = Field(
+        default=None,
+        description='Meaningful only if status is Success. True only if the issuer independently confirmed psp_confirmation_id and network_confirmation_id against the actual payment rail (PSP/network) before issuing this receipt, rather than merely generating them. Absent or false means these confirmation IDs are self-declared by the issuer and MUST NOT be treated as evidence that payment-rail settlement occurred: presence of a confirmation ID proves the issuer asserted a claim, not that the claim was checked.',
+    )
 
 
 class PaymentReceipt(RootModel[PaymentReceiptSuccess | PaymentReceiptError]):
diff --git a/code/sdk/python/ap2/sdk/receipt_wrapper.py b/code/sdk/python/ap2/sdk/receipt_wrapper.py
index 3927bd97..34a2f8a7 100644
--- a/code/sdk/python/ap2/sdk/receipt_wrapper.py
+++ b/code/sdk/python/ap2/sdk/receipt_wrapper.py
@@ -45,6 +45,8 @@ def create_payment_receipt(
         self,
         payment_mandate_content: PaymentMandate,
         reference: str,
+        psp_confirmation_id: str | None = None,
+        network_confirmation_id: str | None = None,
     ) -> PaymentReceipt:
         """Creates a PaymentReceipt model instance.
 
@@ -52,6 +54,18 @@ def create_payment_receipt(
           payment_mandate_content: The closed payment mandate whose PISP this
             receipt inherits as its issuer (when present).
           reference: The payment mandate reference this receipt binds to.
+          psp_confirmation_id: The PSP's own confirmation identifier for this
+            payment, obtained by actually checking the payment rail (e.g. the
+            PSP's settlement/charge API response). If omitted, a locally
+            generated placeholder is used instead and the receipt's
+            `rail_confirmation_verified` field is left unset -- callers MUST
+            NOT treat the resulting receipt as proof that payment-rail
+            settlement occurred unless they supply a real, rail-checked value
+            here (see https://github.com/google-agentic-commerce/AP2/issues/327).
+          network_confirmation_id: The network's own confirmation identifier
+            for this payment. Same caveat as `psp_confirmation_id`: omitting
+            it means the receipt's confirmation IDs are self-declared, not
+            independently verified.
 
         Returns:
           A PaymentReceipt model instance.
@@ -67,11 +81,16 @@ def create_payment_receipt(
             issuer=issuer,
             reference=reference,
         )
+        rail_confirmation_verified = (
+            psp_confirmation_id is not None
+            and network_confirmation_id is not None
+        )
         return PaymentReceipt(
             **base,
             payment_id=payment_id,
-            psp_confirmation_id=payment_id,
-            network_confirmation_id=payment_id,
+            psp_confirmation_id=psp_confirmation_id or payment_id,
+            network_confirmation_id=network_confirmation_id or payment_id,
+            rail_confirmation_verified=rail_confirmation_verified,
         )
 
     def create_checkout_receipt(
diff --git a/code/sdk/python/ap2/tests/receipt_wrapper_tests.py b/code/sdk/python/ap2/tests/receipt_wrapper_tests.py
index c3cfaf75..6ac4dcbe 100644
--- a/code/sdk/python/ap2/tests/receipt_wrapper_tests.py
+++ b/code/sdk/python/ap2/tests/receipt_wrapper_tests.py
@@ -59,6 +59,46 @@ def test_create_payment_receipt_no_pisp(issuer_key):
     assert receipt.root.iss == ''
 
 
+def test_create_payment_receipt_defaults_to_unverified(issuer_key):
+    """Without real rail confirmation IDs, the receipt is honestly unverified.
+
+    Regression test for
+    https://github.com/google-agentic-commerce/AP2/issues/327: a Success
+    receipt must not silently imply payment-rail evidence it does not have.
+    """
+    client = ReceiptClient()
+    reference = 'test_reference'
+    payment_mandate_content = _payment_mandate(pisp=None)
+
+    receipt = client.create_payment_receipt(payment_mandate_content, reference)
+
+    assert receipt.root.status == 'Success'
+    # Placeholder confirmation IDs are still populated (unchanged behavior for
+    # existing callers) ...
+    assert receipt.root.psp_confirmation_id == receipt.root.payment_id
+    assert receipt.root.network_confirmation_id == receipt.root.payment_id
+    # ... but the receipt now says so honestly instead of staying silent.
+    assert receipt.root.rail_confirmation_verified is False
+
+
+def test_create_payment_receipt_with_real_rail_confirmation(issuer_key):
+    """Real, caller-supplied confirmation IDs mark the receipt as verified."""
+    client = ReceiptClient()
+    reference = 'test_reference'
+    payment_mandate_content = _payment_mandate(pisp=None)
+
+    receipt = client.create_payment_receipt(
+        payment_mandate_content,
+        reference,
+        psp_confirmation_id='psp-real-123',
+        network_confirmation_id='network-real-456',
+    )
+
+    assert receipt.root.psp_confirmation_id == 'psp-real-123'
+    assert receipt.root.network_confirmation_id == 'network-real-456'
+    assert receipt.root.rail_confirmation_verified is True
+
+
 def test_create_checkout_receipt():
     """Test creation of a CheckoutReceipt."""
     client = ReceiptClient()
diff --git a/code/sdk/schemas/ap2/payment_receipt.json b/code/sdk/schemas/ap2/payment_receipt.json
index f58ef045..da21c2c6 100644
--- a/code/sdk/schemas/ap2/payment_receipt.json
+++ b/code/sdk/schemas/ap2/payment_receipt.json
@@ -40,6 +40,10 @@
     "network_confirmation_id": {
       "type": "string",
       "description": "A unique identifier for the transaction confirmation at the network. Present only if status is Success."
+    },
+    "rail_confirmation_verified": {
+      "type": "boolean",
+      "description": "Meaningful only if status is Success. True only if the issuer independently confirmed psp_confirmation_id and network_confirmation_id against the actual payment rail (PSP/network) before issuing this receipt, rather than merely generating them. Absent or false means these confirmation IDs are self-declared by the issuer and MUST NOT be treated as evidence that payment-rail settlement occurred: presence of a confirmation ID proves the issuer asserted a claim, not that the claim was checked."
     }
   },
   "required": [