diff --git a/.stats.yml b/.stats.yml
index 49961a7f..d93eaabd 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,2 +1,2 @@
 configured_endpoints: 3
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/anthropic-fb94a03f85580f7eacef034518becfb463502e6d74b0f7932f6153239de23a5b.yml
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/anthropic-209cf750b141ebe030a31486ce555fa23b87436cd4235e997b989dfe70dd1b0b.yml
diff --git a/src/resources/beta/prompt-caching/messages.ts b/src/resources/beta/prompt-caching/messages.ts
index 77f4d475..4668d11d 100644
--- a/src/resources/beta/prompt-caching/messages.ts
+++ b/src/resources/beta/prompt-caching/messages.ts
@@ -583,6 +583,14 @@ export namespace MessageCreateParams {
    */
   export interface ToolChoiceAuto {
     type: 'auto';
+
+    /**
+     * Whether to disable parallel tool use.
+     *
+     * Defaults to `false`. If set to `true`, the model will output at most one tool
+     * use.
+     */
+    disable_parallel_tool_use?: boolean;
   }
 
   /**
@@ -590,6 +598,14 @@ export namespace MessageCreateParams {
    */
   export interface ToolChoiceAny {
     type: 'any';
+
+    /**
+     * Whether to disable parallel tool use.
+     *
+     * Defaults to `false`. If set to `true`, the model will output exactly one tool
+     * use.
+     */
+    disable_parallel_tool_use?: boolean;
   }
 
   /**
@@ -602,6 +618,14 @@ export namespace MessageCreateParams {
     name: string;
 
     type: 'tool';
+
+    /**
+     * Whether to disable parallel tool use.
+     *
+     * Defaults to `false`. If set to `true`, the model will output exactly one tool
+     * use.
+     */
+    disable_parallel_tool_use?: boolean;
   }
 
   export type MessageCreateParamsNonStreaming = PromptCachingMessagesAPI.MessageCreateParamsNonStreaming;
diff --git a/src/resources/messages.ts b/src/resources/messages.ts
index 2bcd89a1..9c5e46d7 100644
--- a/src/resources/messages.ts
+++ b/src/resources/messages.ts
@@ -690,6 +690,14 @@ export namespace MessageCreateParams {
    */
   export interface ToolChoiceAuto {
     type: 'auto';
+
+    /**
+     * Whether to disable parallel tool use.
+     *
+     * Defaults to `false`. If set to `true`, the model will output at most one tool
+     * use.
+     */
+    disable_parallel_tool_use?: boolean;
   }
 
   /**
@@ -697,6 +705,14 @@ export namespace MessageCreateParams {
    */
   export interface ToolChoiceAny {
     type: 'any';
+
+    /**
+     * Whether to disable parallel tool use.
+     *
+     * Defaults to `false`. If set to `true`, the model will output exactly one tool
+     * use.
+     */
+    disable_parallel_tool_use?: boolean;
   }
 
   /**
@@ -709,6 +725,14 @@ export namespace MessageCreateParams {
     name: string;
 
     type: 'tool';
+
+    /**
+     * Whether to disable parallel tool use.
+     *
+     * Defaults to `false`. If set to `true`, the model will output exactly one tool
+     * use.
+     */
+    disable_parallel_tool_use?: boolean;
   }
 
   export type MessageCreateParamsNonStreaming = MessagesAPI.MessageCreateParamsNonStreaming;
diff --git a/tests/api-resources/beta/prompt-caching/messages.test.ts b/tests/api-resources/beta/prompt-caching/messages.test.ts
index e0e73f98..e7e2fada 100644
--- a/tests/api-resources/beta/prompt-caching/messages.test.ts
+++ b/tests/api-resources/beta/prompt-caching/messages.test.ts
@@ -34,7 +34,7 @@ describe('resource messages', () => {
       stream: false,
       system: [{ text: "Today's date is 2024-06-01.", type: 'text', cache_control: { type: 'ephemeral' } }],
       temperature: 1,
-      tool_choice: { type: 'auto' },
+      tool_choice: { type: 'auto', disable_parallel_tool_use: true },
       tools: [
         {
           input_schema: {
diff --git a/tests/api-resources/messages.test.ts b/tests/api-resources/messages.test.ts
index 5592a7c4..870e9b53 100644
--- a/tests/api-resources/messages.test.ts
+++ b/tests/api-resources/messages.test.ts
@@ -34,7 +34,7 @@ describe('resource messages', () => {
       stream: false,
       system: [{ text: "Today's date is 2024-06-01.", type: 'text' }],
       temperature: 1,
-      tool_choice: { type: 'auto' },
+      tool_choice: { type: 'auto', disable_parallel_tool_use: true },
       tools: [
         {
           input_schema: {