feat: add User-Agent header to MCP HTTP requests (#6988)

crates/goose/src/agents/extension_manager.rs

@@ -363,6 +363,9 @@ fn substitute_env_vars(value: &str, env_map: &HashMap<String, String>) -> String
     result
 }
 
+const GOOSE_USER_AGENT: reqwest::header::HeaderValue =
+    reqwest::header::HeaderValue::from_static(concat!("goose/", env!("CARGO_PKG_VERSION")));
+
 async fn create_streamable_http_client(
     uri: &str,
     timeout: Option<u64>,
@@ -372,6 +375,9 @@ async fn create_streamable_http_client(
     provider: SharedProvider,
 ) -> ExtensionResult<Box<dyn McpClientTrait>> {
     let mut default_headers = HeaderMap::new();
+
+    default_headers.insert(reqwest::header::USER_AGENT, GOOSE_USER_AGENT);
+
     for (key, value) in headers {
         let substituted_value = substitute_env_vars(value, all_envs);
         default_headers.insert(
@@ -405,7 +411,15 @@ async fn create_streamable_http_client(
         let am = oauth_flow(&uri.to_string(), &name.to_string())
             .await
             .map_err(|_| ExtensionError::SetupError("auth error".to_string()))?;
-        let auth_client = AuthClient::new(reqwest::Client::default(), am);
+        let mut auth_headers = HeaderMap::new();
+        auth_headers.insert(reqwest::header::USER_AGENT, GOOSE_USER_AGENT);
+        let auth_http_client = reqwest::Client::builder()
+            .default_headers(auth_headers)
+            .build()
+            .map_err(|_| {
+                ExtensionError::ConfigError("could not construct http client".to_string())
+            })?;
+        let auth_client = AuthClient::new(auth_http_client, am);
         let transport = StreamableHttpClientTransport::with_client(
             auth_client,
             StreamableHttpClientTransportConfig {