diff --git a/.cspell/custom-words.txt b/.cspell/custom-words.txt
index ce73c361..2c233390 100644
--- a/.cspell/custom-words.txt
+++ b/.cspell/custom-words.txt
@@ -118,6 +118,7 @@ okhttp
 opentelemetry
 otelgrpc
 otelhttp
+otherpisp
 Otherville
 OURCYGPATTERN
 Palo
@@ -127,6 +128,10 @@ Payoneer
 paypal
 Payplug
 pids
+PISP
+Pisp
+pisp
+Pisps
 pmezard
 proguard
 Proguard
@@ -149,6 +154,7 @@ ropeproject
 RPCURL
 Rulebook
 screenreaders
+SECP
 setlocal
 sharedpref
 Shopcider
diff --git a/.github/workflows/linter.yaml b/.github/workflows/linter.yaml
index fea1b9c1..e6d040c0 100644
--- a/.github/workflows/linter.yaml
+++ b/.github/workflows/linter.yaml
@@ -23,7 +23,8 @@ jobs:
           LOG_LEVEL: WARN
           SHELLCHECK_OPTS: -e SC1091 -e 2086
           VALIDATE_ALL_CODEBASE: false
-          FILTER_REGEX_EXCLUDE: "^(\\.github/|\\.vscode/|code/samples/).*|CODE_OF_CONDUCT.md|CHANGELOG.md"
+          FILTER_REGEX_EXCLUDE: "^(\\.github/|\\.vscode/|code/samples/|code/web-client/).*|CODE_OF_CONDUCT.md|CHANGELOG.md"
+          VALIDATE_BIOME_LINT: false
           VALIDATE_BIOME_FORMAT: false
           VALIDATE_PYTHON_BLACK: false
           VALIDATE_PYTHON_FLAKE8: false
diff --git a/code/sdk/python/ap2/sdk/constraints.py b/code/sdk/python/ap2/sdk/constraints.py
index 48aed798..cc21094e 100644
--- a/code/sdk/python/ap2/sdk/constraints.py
+++ b/code/sdk/python/ap2/sdk/constraints.py
@@ -243,12 +243,20 @@ def evaluate(
         instrument = closed_mandate.payment_instrument
         if not instrument:
             return ['Missing payment instrument in closed mandate']
+        # Match on both type and id. Matching on id alone lets a closed
+        # instrument of a different type (e.g. {id: 'x', type: 'bank'}) satisfy
+        # an allowed {id: 'x', type: 'card'}, since id uniqueness is not defined
+        # across types. Requiring (type, id) prevents that instrument-type
+        # confusion.
         if any(
-            allowed.id == instrument.id
+            allowed.type == instrument.type and allowed.id == instrument.id
             for allowed in self.constraint.allowed
         ):
             return []
-        return [f'Payment instrument {instrument.id} not in allowed list']
+        return [
+            f'Payment instrument (type={instrument.type}, id={instrument.id}) '
+            'not in allowed list'
+        ]
 
 
 class AllowedPispEvaluator(PaymentConstraintEvaluator):
diff --git a/code/sdk/python/ap2/tests/constraints_tests.py b/code/sdk/python/ap2/tests/constraints_tests.py
index 910c97fc..783c1037 100644
--- a/code/sdk/python/ap2/tests/constraints_tests.py
+++ b/code/sdk/python/ap2/tests/constraints_tests.py
@@ -412,6 +412,50 @@ def test_payment_allowed_payment_instrument_mismatch():
     assert any('not in allowed list' in v for v in violations)
 
 
+def test_payment_allowed_payment_instrument_same_id_different_type_rejected():
+    """A closed instrument with an allowed id but a different type is rejected.
+
+    id uniqueness is not defined across instrument types, so matching on id
+    alone would let {id: 'pi-1', type: 'bank'} satisfy an allowed
+    {id: 'pi-1', type: 'card'}. Matching requires (type, id).
+    """
+    violations = check_payment_constraints(
+        _open_payment(
+            constraints=[
+                AllowedPaymentInstruments(
+                    allowed=[
+                        PaymentInstrument(id='pi-1', type='card')
+                    ],
+                ),
+            ]
+        ),
+        _closed_payment(
+            payment_instrument=PaymentInstrument(id='pi-1', type='bank')
+        ),
+    )
+    assert any('not in allowed list' in v for v in violations)
+
+
+def test_payment_allowed_payment_instrument_type_and_id_match():
+    """A closed instrument matching an allowed (type, id) passes."""
+    violations = check_payment_constraints(
+        _open_payment(
+            constraints=[
+                AllowedPaymentInstruments(
+                    allowed=[
+                        PaymentInstrument(id='pi-1', type='card'),
+                        PaymentInstrument(id='pi-1', type='bank'),
+                    ],
+                ),
+            ]
+        ),
+        _closed_payment(
+            payment_instrument=PaymentInstrument(id='pi-1', type='bank')
+        ),
+    )
+    assert violations == []
+
+
 # ── check_payment_constraints – budget ───────────────────────────────────