diff --git a/.castiron.stats.yml b/.castiron.stats.yml
index 5163f06e2..cd6bea4b0 100644
--- a/.castiron.stats.yml
+++ b/.castiron.stats.yml
@@ -1,8 +1,8 @@
 schema_version: 1
-generation_id: 7843acb1-8aa3-496f-94e5-534cf4dad401
-openapi_spec_hash: 8d140aa0dc64006644485ae8bd392ef7
-openapi_transformed_spec_hash: ff03494596180c39501a59a825cfd47d
+generation_id: 2d4ae8bf-2a9b-4ccb-897f-70b290c9aaaa
+openapi_spec_hash: 0da20f2f738fd442b9384a102b042bc2
+openapi_transformed_spec_hash: 8ddaf5c9df9e4313ddcfdf9b7159b4fe
 config_hash: 687b8a0f9aff551a4cbf86b2ac82c288
-codegen_sha: e94296866fda8d502c197ef1efa4e9c5f9c75ae1
-codegen_hash: e0a95dbd83e20df47edc0c0e07a3dc6210bc663b83ed7cf38c42db74bf217eb9
-public_codegen_sha: fcbf15119800f60318af8cc58e2e4c48638992cd
+codegen_sha: a697e515acc5e1defef4842e6e021e3eed6aeefa
+codegen_hash: 3296b4c129aab733f5c5cd8b270fbf72c85482d6290e58ffde500e07a648c186
+public_codegen_sha: 9a8cc237de0338cd194bbb4c9ad52bf90746f464
diff --git a/api_reference/openapi.transformed.yml b/api_reference/openapi.transformed.yml
index 58b034b16..09166f9c0 100644
--- a/api_reference/openapi.transformed.yml
+++ b/api_reference/openapi.transformed.yml
@@ -83389,6 +83389,7 @@ components:
       - project_spend_limit_exceeded
       - organization_spend_limit_exceeded
       - organization_usage_limit_exceeded
+      - billing_not_active
       - credit_balance_exhausted
       - rate_limit_exceeded
       - flex_unavailable
@@ -83412,6 +83413,7 @@ components:
       - The project has reached its enforced spend limit.
       - The organization has reached its enforced spend limit.
       - The organization has reached its OpenAI-assigned usage limit.
+      - Billing is not active for the account.
       - The organization has no API credits remaining.
       - The request exceeds the available rate limit.
       - Flex processing is temporarily unavailable.
diff --git a/src/resources/beta/agents/agents.ts b/src/resources/beta/agents/agents.ts
index 0f7f6a232..5c1ed6ee2 100644
--- a/src/resources/beta/agents/agents.ts
+++ b/src/resources/beta/agents/agents.ts
@@ -5090,6 +5090,7 @@ export interface SessionTurnError {
    *   enforced spend limit.
    * - `organization_usage_limit_exceeded` - The organization has reached its
    *   OpenAI-assigned usage limit.
+   * - `billing_not_active` - Billing is not active for the account.
    * - `credit_balance_exhausted` - The organization has no API credits remaining.
    * - `rate_limit_exceeded` - The request exceeds the available rate limit.
    * - `flex_unavailable` - Flex processing is temporarily unavailable.
@@ -5119,6 +5120,7 @@ export interface SessionTurnError {
     | 'project_spend_limit_exceeded'
     | 'organization_spend_limit_exceeded'
     | 'organization_usage_limit_exceeded'
+    | 'billing_not_active'
     | 'credit_balance_exhausted'
     | 'rate_limit_exceeded'
     | 'flex_unavailable'