Set user-agent (#2230)

Use the same well-defined value in all cases when sending user-agent
header

codex-rs/core/src/client.rs

@@ -38,6 +38,7 @@ use crate::model_provider_info::WireApi;
 use crate::models::ResponseItem;
 use crate::openai_tools::create_tools_json_for_responses_api;
 use crate::protocol::TokenUsage;
+use crate::user_agent::get_codex_user_agent;
 use crate::util::backoff;
 use std::sync::Arc;
 
@@ -208,6 +209,7 @@ impl ModelClient {
                 .as_deref()
                 .unwrap_or("codex_cli_rs");
             req_builder = req_builder.header("originator", originator);
+            req_builder = req_builder.header("User-Agent", get_codex_user_agent(Some(originator)));
 
             let res = req_builder.send().await;
             if let Ok(resp) = &res {

codex-rs/core/src/lib.rs

@@ -47,6 +47,7 @@ pub mod seatbelt;
 pub mod shell;
 pub mod spawn;
 pub mod turn_diff_tracker;
+pub mod user_agent;
 mod user_notification;
 pub mod util;
 pub use apply_patch::CODEX_APPLY_PATCH_ARG1;

codex-rs/core/src/user_agent.rs

@@ -0,0 +1,36 @@
+const DEFAULT_ORIGINATOR: &str = "codex_cli_rs";
+
+pub fn get_codex_user_agent(originator: Option<&str>) -> String {
+    let build_version = env!("CARGO_PKG_VERSION");
+    let os_info = os_info::get();
+    format!(
+        "{}/{build_version} ({} {}; {})",
+        originator.unwrap_or(DEFAULT_ORIGINATOR),
+        os_info.os_type(),
+        os_info.version(),
+        os_info.architecture().unwrap_or("unknown"),
+    )
+}
+
+#[cfg(test)]
+#[allow(clippy::unwrap_used)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_codex_user_agent() {
+        let user_agent = get_codex_user_agent(None);
+        assert!(user_agent.starts_with("codex_cli_rs/"));
+    }
+
+    #[test]
+    #[cfg(target_os = "macos")]
+    fn test_macos() {
+        use regex_lite::Regex;
+        let user_agent = get_codex_user_agent(None);
+        let re =
+            Regex::new(r"^codex_cli_rs/\d+\.\d+\.\d+ \(Mac OS \d+\.\d+\.\d+; (x86_64|arm64)\)$")
+                .unwrap();
+        assert!(re.is_match(&user_agent));
+    }
+}