Fix error location in document retrieval

Author: 姚临倾

crates/rmcp-macros/src/tool.rs

@@ -214,6 +214,22 @@ pub(crate) fn tool_impl_item(attr: TokenStream, mut input: ItemImpl) -> syn::Res
     let tool_impl_attr: ToolImplItemAttrs = syn::parse2(attr)?;
     let tool_box_ident = tool_impl_attr.tool_box;
     let mut extend_quote = None;
+    let description = if let Some(expr) = tool_impl_attr.description {
+        // Use explicitly provided description if available
+        expr
+    } else {
+        // Try to extract documentation comments
+        let doc_content = input
+            .attrs
+            .iter()
+            .filter_map(extract_doc_line)
+            .collect::<Vec<_>>()
+            .join("\n");
+
+        parse_quote! {
+                #doc_content.trim().to_string()
+        }
+    };
     // get all tool function ident
     let mut tool_fn_idents = Vec::new();
     for item in &input.items {
@@ -305,22 +321,6 @@ pub(crate) fn tool_impl_item(attr: TokenStream, mut input: ItemImpl) -> syn::Res
 
         if tool_impl_attr.default_build {
             let struct_name = input.self_ty.clone();
-            let description = if let Some(expr) = tool_impl_attr.description {
-                // Use explicitly provided description if available
-                expr
-            } else {
-                // Try to extract documentation comments
-                let doc_content = input
-                    .attrs
-                    .iter()
-                    .filter_map(extract_doc_line)
-                    .collect::<Vec<_>>()
-                    .join("\n");
-
-                parse_quote! {
-                        #doc_content.trim().to_string()
-                }
-            };
             let generic = &input.generics;
             let extend = quote! {
                 impl #generic rmcp::handler::server::ServerHandler for #struct_name {