diff --git a/codex-rs/core/src/client_common.rs b/codex-rs/core/src/client_common.rs
index 913bb22321..27d52b490f 100644
--- a/codex-rs/core/src/client_common.rs
+++ b/codex-rs/core/src/client_common.rs
@@ -193,10 +193,8 @@ pub(crate) mod tools {
         Function(ResponsesApiTool),
         #[serde(rename = "local_shell")]
         LocalShell {},
-        // TODO: Understand why we get an error on web_search although the API docs say it's supported.
-        // https://platform.openai.com/docs/guides/tools-web-search?api-mode=responses#:~:text=%7B%20type%3A%20%22web_search%22%20%7D%2C
         #[serde(rename = "web_search")]
-        WebSearch {},
+        WebSearch(WebSearchTool),
         #[serde(rename = "custom")]
         Freeform(FreeformTool),
     }
@@ -206,7 +204,7 @@ pub(crate) mod tools {
             match self {
                 ToolSpec::Function(tool) => tool.name.as_str(),
                 ToolSpec::LocalShell {} => "local_shell",
-                ToolSpec::WebSearch {} => "web_search",
+                ToolSpec::WebSearch(_) => "web_search",
                 ToolSpec::Freeform(tool) => tool.name.as_str(),
             }
         }
@@ -236,6 +234,11 @@ pub(crate) mod tools {
         pub(crate) strict: bool,
         pub(crate) parameters: JsonSchema,
     }
+
+    #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+    pub struct WebSearchTool {
+        pub(crate) external_web_access: bool,
+    }
 }
 
 pub struct ResponseStream {
diff --git a/codex-rs/core/src/tools/spec.rs b/codex-rs/core/src/tools/spec.rs
index 0ac91755c2..5108d79667 100644
--- a/codex-rs/core/src/tools/spec.rs
+++ b/codex-rs/core/src/tools/spec.rs
@@ -1,5 +1,6 @@
 use crate::client_common::tools::ResponsesApiTool;
 use crate::client_common::tools::ToolSpec;
+use crate::client_common::tools::WebSearchTool;
 use crate::features::Feature;
 use crate::features::Features;
 use crate::models_manager::model_family::ModelFamily;
@@ -1094,7 +1095,9 @@ pub(crate) fn build_specs(
     }
 
     if config.web_search_request {
-        builder.push_spec(ToolSpec::WebSearch {});
+        builder.push_spec(ToolSpec::WebSearch(WebSearchTool {
+            external_web_access: false,
+        }));
     }
 
     if config.include_view_image_tool {