diff --git a/.changeset/rich-buses-marry.md b/.changeset/rich-buses-marry.md
new file mode 100644
index 00000000..2183dd1d
--- /dev/null
+++ b/.changeset/rich-buses-marry.md
@@ -0,0 +1,5 @@
+---
+"@openai/agents-openai": patch
+---
+
+feat: handle unknown hosted tools in responses model
diff --git a/packages/agents-openai/src/openaiResponsesModel.ts b/packages/agents-openai/src/openaiResponsesModel.ts
index d6767618..c37a8756 100644
--- a/packages/agents-openai/src/openaiResponsesModel.ts
+++ b/packages/agents-openai/src/openaiResponsesModel.ts
@@ -175,6 +175,11 @@ function converTool<_TContext = unknown>(
         },
         include: undefined,
       };
+    } else if (tool.providerData) {
+      return {
+        tool: tool.providerData as unknown as OpenAI.Responses.Tool,
+        include: undefined,
+      };
     }
   }
 
diff --git a/packages/agents-openai/test/openaiResponsesModel.helpers.test.ts b/packages/agents-openai/test/openaiResponsesModel.helpers.test.ts
index a4accdf1..68f60c68 100644
--- a/packages/agents-openai/test/openaiResponsesModel.helpers.test.ts
+++ b/packages/agents-openai/test/openaiResponsesModel.helpers.test.ts
@@ -125,6 +125,23 @@ describe('converTool', () => {
       quality: undefined,
       size: undefined,
     });
+
+    const custom = converTool({
+      type: 'hosted_tool',
+      providerData: {
+        type: 'mcp',
+        server_label: 'deepwiki',
+        server_url: 'https://mcp.deepwiki.com/mcp',
+        require_approval: 'never',
+      },
+    } as any);
+
+    expect(custom.tool).toEqual({
+      type: 'mcp',
+      server_label: 'deepwiki',
+      server_url: 'https://mcp.deepwiki.com/mcp',
+      require_approval: 'never',
+    });
   });
 
   it('throws on unsupported tool', () => {