Attribute OpenAI docs MCP requests to Codex (#33424)

## What changed

- Add `source=codex` to requests sent to the OpenAI developer docs MCP endpoint.
- Preserve OAuth discovery URLs and leave clients for other MCP servers unchanged.

## Testing

- Add unit coverage for regular and streaming HTTP requests, OAuth discovery, and non-docs MCP clients.

GitOrigin-RevId: d04e19fe6fc2db0b5cd7bfb429f0cb821c49b28a

codex-rs/codex-mcp/src/lib.rs

@@ -86,6 +86,7 @@ pub(crate) mod codex_apps;
 pub(crate) mod connection_manager;
 pub(crate) mod elicitation;
 pub(crate) mod mcp;
+mod openai_docs_source_attribution;
 mod plugin_config;
 mod resource_client;
 pub(crate) mod rmcp_client;

codex-rs/codex-mcp/src/openai_docs_source_attribution.rs

@@ -0,0 +1,56 @@
+use std::sync::Arc;
+
+use codex_exec_server::ExecServerError;
+use codex_exec_server::HttpClient;
+use codex_exec_server::HttpRequestParams;
+use codex_exec_server::HttpRequestResponse;
+use codex_exec_server::HttpResponseBodyStream;
+use futures::future::BoxFuture;
+
+const OPENAI_DEVELOPER_DOCS_MCP_URL: &str = "https://developers.openai.com/mcp";
+const OPENAI_DEVELOPER_DOCS_MCP_CODEX_URL: &str = "https://developers.openai.com/mcp?source=codex";
+
+pub(crate) fn maybe_with_openai_docs_source_attribution(
+    mcp_server_url: &str,
+    http_client: Arc<dyn HttpClient>,
+) -> Arc<dyn HttpClient> {
+    if mcp_server_url == OPENAI_DEVELOPER_DOCS_MCP_URL {
+        Arc::new(OpenAiDocsHttpClient { http_client })
+    } else {
+        http_client
+    }
+}
+
+struct OpenAiDocsHttpClient {
+    http_client: Arc<dyn HttpClient>,
+}
+
+impl OpenAiDocsHttpClient {
+    fn attribute_mcp_request(&self, params: &mut HttpRequestParams) {
+        if params.url == OPENAI_DEVELOPER_DOCS_MCP_URL {
+            params.url = OPENAI_DEVELOPER_DOCS_MCP_CODEX_URL.to_string();
+        }
+    }
+}
+
+impl HttpClient for OpenAiDocsHttpClient {
+    fn http_request(
+        &self,
+        mut params: HttpRequestParams,
+    ) -> BoxFuture<'_, Result<HttpRequestResponse, ExecServerError>> {
+        self.attribute_mcp_request(&mut params);
+        self.http_client.http_request(params)
+    }
+
+    fn http_request_stream(
+        &self,
+        mut params: HttpRequestParams,
+    ) -> BoxFuture<'_, Result<(HttpRequestResponse, HttpResponseBodyStream), ExecServerError>> {
+        self.attribute_mcp_request(&mut params);
+        self.http_client.http_request_stream(params)
+    }
+}
+
+#[cfg(test)]
+#[path = "openai_docs_source_attribution_tests.rs"]
+mod tests;

codex-rs/codex-mcp/src/openai_docs_source_attribution_tests.rs

@@ -0,0 +1,92 @@
+use std::sync::Arc;
+use std::sync::Mutex;
+
+use codex_exec_server::ExecServerError;
+use codex_exec_server::HttpClient;
+use codex_exec_server::HttpRedirectPolicy;
+use codex_exec_server::HttpRequestParams;
+use codex_exec_server::HttpRequestResponse;
+use codex_exec_server::HttpResponseBodyStream;
+use futures::FutureExt;
+use futures::future::BoxFuture;
+use pretty_assertions::assert_eq;
+
+use super::OPENAI_DEVELOPER_DOCS_MCP_CODEX_URL;
+use super::OPENAI_DEVELOPER_DOCS_MCP_URL;
+use super::maybe_with_openai_docs_source_attribution;
+
+#[derive(Default)]
+struct RecordingHttpClient {
+    urls: Mutex<Vec<String>>,
+}
+
+impl HttpClient for RecordingHttpClient {
+    fn http_request(
+        &self,
+        params: HttpRequestParams,
+    ) -> BoxFuture<'_, Result<HttpRequestResponse, ExecServerError>> {
+        self.urls.lock().unwrap().push(params.url);
+        async { Err(ExecServerError::HttpRequest("test response".to_string())) }.boxed()
+    }
+
+    fn http_request_stream(
+        &self,
+        params: HttpRequestParams,
+    ) -> BoxFuture<'_, Result<(HttpRequestResponse, HttpResponseBodyStream), ExecServerError>> {
+        self.urls.lock().unwrap().push(params.url);
+        async { Err(ExecServerError::HttpRequest("test response".to_string())) }.boxed()
+    }
+}
+
+fn request(url: &str) -> HttpRequestParams {
+    HttpRequestParams {
+        method: "POST".to_string(),
+        url: url.to_string(),
+        headers: Vec::new(),
+        body: None,
+        timeout_ms: None,
+        redirect_policy: HttpRedirectPolicy::Follow,
+        request_id: "test-request".to_string(),
+        stream_response: true,
+    }
+}
+
+#[tokio::test]
+async fn attributes_only_docs_mcp_requests() {
+    let recording_client = Arc::new(RecordingHttpClient::default());
+    let http_client = maybe_with_openai_docs_source_attribution(
+        OPENAI_DEVELOPER_DOCS_MCP_URL,
+        recording_client.clone(),
+    );
+
+    let _ = http_client
+        .http_request_stream(request(OPENAI_DEVELOPER_DOCS_MCP_URL))
+        .await;
+    let _ = http_client
+        .http_request(request(
+            "https://developers.openai.com/.well-known/oauth-protected-resource/mcp",
+        ))
+        .await;
+
+    assert_eq!(
+        recording_client.urls.lock().unwrap().as_slice(),
+        [
+            OPENAI_DEVELOPER_DOCS_MCP_CODEX_URL,
+            "https://developers.openai.com/.well-known/oauth-protected-resource/mcp",
+        ]
+    );
+}
+
+#[test]
+fn leaves_other_mcp_clients_unwrapped() {
+    let recording_client = Arc::new(RecordingHttpClient::default());
+    let http_client = maybe_with_openai_docs_source_attribution(
+        "https://example.com/mcp",
+        recording_client.clone(),
+    );
+
+    assert!(Arc::ptr_eq(
+        &http_client,
+        &(recording_client as Arc<dyn HttpClient>)
+    ));
+}

codex-rs/codex-mcp/src/rmcp_client.rs

@@ -25,6 +25,7 @@ use crate::codex_apps::prepare_openai_file_params_for_model;
 use crate::elicitation::ElicitationRequestManager;
 use crate::mcp::CODEX_APPS_MCP_SERVER_NAME;
 use crate::mcp::ToolPluginProvenance;
+use crate::openai_docs_source_attribution::maybe_with_openai_docs_source_attribution;
 use crate::runtime::McpRuntimeContext;
 use crate::runtime::emit_duration;
 use crate::server::EffectiveMcpServer;
@@ -1077,6 +1078,7 @@ async fn make_rmcp_client(
                 || Arc::new(ReqwestHttpClient) as Arc<dyn HttpClient>,
                 |environment| environment.get_http_client(),
             );
+            let http_client = maybe_with_openai_docs_source_attribution(&url, http_client);
             let resolved_bearer_token =
                 match resolve_bearer_token(server_name, bearer_token_env_var.as_deref()) {
                     Ok(token) => token,