diff --git a/.gitignore b/.gitignore
index 1d80fbf..23a38f5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -72,5 +72,7 @@ Untitled.ipynb
 *.iml
 # End of https://www.toptal.com/developers/gitignore/api/python
 
+# asdf / mise version managers (local dev only; supported versions live in setup.cfg + CI)
+.tool-versions
 mise.toml
 .claude
diff --git a/lago_python_client/models/__init__.py b/lago_python_client/models/__init__.py
index fbd141a..7fcf802 100644
--- a/lago_python_client/models/__init__.py
+++ b/lago_python_client/models/__init__.py
@@ -234,7 +234,7 @@
 from .payment_request import PaymentRequest as PaymentRequest
 from .payment_method import PaymentMethod as PaymentMethod, PaymentMethodResponse as PaymentMethodResponse
 from .plan import Plan as Plan
-from .subscription import Subscription as Subscription
+from .subscription import ActivationRuleInput as ActivationRuleInput, Subscription as Subscription
 from .tax import (
     Tax as Tax,
 )
diff --git a/lago_python_client/models/subscription.py b/lago_python_client/models/subscription.py
index 408ec60..807ca74 100644
--- a/lago_python_client/models/subscription.py
+++ b/lago_python_client/models/subscription.py
@@ -8,6 +8,11 @@
 from .plan import PlanOverrides
 
 
+class ActivationRuleInput(BaseModel):
+    type: Optional[str]
+    timeout_hours: Optional[int]
+
+
 class Subscription(BaseModel):
     plan_code: Optional[str]
     external_customer_id: Optional[str]
@@ -20,6 +25,7 @@ class Subscription(BaseModel):
     payment_method: Optional[PaymentMethod]
     invoice_custom_section: Optional[InvoiceCustomSectionInput]
     consolidate_invoice: Optional[bool]
+    activation_rules: Optional[List[ActivationRuleInput]]
 
 
 class Subscriptions(BaseModel):
@@ -28,6 +34,16 @@ class Subscriptions(BaseModel):
     terminated_at: Optional[str]
 
 
+class ActivationRuleResponse(BaseResponseModel):
+    lago_id: Optional[str]
+    type: Optional[str]
+    timeout_hours: Optional[int]
+    status: Optional[str]
+    expires_at: Optional[str]
+    created_at: Optional[str]
+    updated_at: Optional[str]
+
+
 class SubscriptionResponse(BaseResponseModel):
     lago_id: str
     lago_customer_id: Optional[str]
@@ -57,6 +73,9 @@ class SubscriptionResponse(BaseResponseModel):
     payment_method: Optional[PaymentMethod]
     applied_invoice_custom_sections: Optional[AppliedInvoiceCustomSections]
     consolidate_invoice: Optional[bool]
+    cancellation_reason: Optional[str]
+    activated_at: Optional[str]
+    activation_rules: Optional[List[ActivationRuleResponse]]
 
 
 class SubscriptionsResponse(BaseResponseModel):
diff --git a/tests/fixtures/subscription.json b/tests/fixtures/subscription.json
index 24412ab..ffc6074 100644
--- a/tests/fixtures/subscription.json
+++ b/tests/fixtures/subscription.json
@@ -37,6 +37,19 @@
           "name": "Section Name"
         }
       }
+    ],
+    "cancellation_reason": "payment_failed",
+    "activated_at": "2022-04-29T09:00:00Z",
+    "activation_rules": [
+      {
+        "lago_id": "ar_123",
+        "type": "payment",
+        "timeout_hours": 48,
+        "status": "pending",
+        "expires_at": "2022-04-29T10:59:51Z",
+        "created_at": "2022-04-29T08:59:51Z",
+        "updated_at": "2022-04-29T08:59:51Z"
+      }
     ]
   }
 }
diff --git a/tests/test_subscription_client.py b/tests/test_subscription_client.py
index 2512e42..b0af46b 100644
--- a/tests/test_subscription_client.py
+++ b/tests/test_subscription_client.py
@@ -8,6 +8,7 @@
 from lago_python_client.exceptions import LagoApiError
 from lago_python_client.mixins import DEFAULT_TIMEOUT
 from lago_python_client.models import (
+    ActivationRuleInput,
     Charge,
     ChargeFilter,
     FixedCharge,
@@ -108,6 +109,26 @@ def test_valid_create_subscriptions_request_with_payment_method(httpx_mock: HTTP
     assert response.payment_method.payment_method_id == "pm_123"
 
 
+def test_valid_create_subscriptions_request_with_activation_rules(httpx_mock: HTTPXMock):
+    client = Client(api_key="886fe239-927d-4072-ab72-6dd345e8dd0d")
+
+    httpx_mock.add_response(
+        method="POST",
+        url="https://api.getlago.com/api/v1/subscriptions",
+        content=mock_response(),
+    )
+    subscription = create_subscription()
+    subscription.activation_rules = [ActivationRuleInput(type="payment", timeout_hours=48)]
+    response = client.subscriptions.create(subscription)
+
+    assert response.external_customer_id == "5eb02857-a71e-4ea2-bcf9-57d3a41bc6ba"
+    assert response.cancellation_reason == "payment_failed"
+    assert response.activated_at == "2022-04-29T09:00:00Z"
+    assert response.activation_rules[0].type == "payment"
+    assert response.activation_rules[0].timeout_hours == 48
+    assert response.activation_rules[0].status == "pending"
+
+
 def test_invalid_create_subscriptions_request(httpx_mock: HTTPXMock):
     client = Client(api_key="invalid")