feat: enhance directory_tree response with metadata (#30)

Author: hashemix

src/fs_service.rs

@@ -522,7 +522,7 @@ impl FileSystemService {
         max_depth: Option<usize>,
         max_files: Option<usize>,
         current_count: &mut usize,
-    ) -> ServiceResult<Value> {
+    ) -> ServiceResult<(Value, bool)> {
         let valid_path = self.validate_path(root_path.as_ref())?;
 
         let metadata = fs::metadata(&valid_path)?;
@@ -533,6 +533,7 @@ impl FileSystemService {
         }
 
         let mut children = Vec::new();
+        let mut reached_max_depth = false;
 
         if max_depth != Some(0) {
             for entry in WalkDir::new(valid_path)
@@ -568,17 +569,21 @@ impl FileSystemService {
 
                 if metadata.is_dir() {
                     let next_depth = max_depth.map(|d| d - 1);
-                    let child_children =
+                    let (child_children, child_reached_max_depth) =
                         self.directory_tree(child_path, next_depth, max_files, current_count)?;
                     json_entry
                         .as_object_mut()
                         .unwrap()
                         .insert("children".to_string(), child_children);
+                    reached_max_depth |= child_reached_max_depth;
                 }
                 children.push(json_entry);
             }
+        } else {
+            // If max_depth is 0, we skip processing this directory's children
+            reached_max_depth = true;
         }
-        Ok(Value::Array(children))
+        Ok((Value::Array(children), reached_max_depth))
     }
 
     pub fn create_unified_diff(

src/tools/directory_tree.rs

@@ -1,7 +1,7 @@
 use rust_mcp_sdk::macros::{mcp_tool, JsonSchema};
 use rust_mcp_sdk::schema::TextContent;
 use rust_mcp_sdk::schema::{schema_utils::CallToolError, CallToolResult};
-use serde_json::json;
+use serde_json::{json, Map, Value};
 
 use crate::error::ServiceError;
 use crate::fs_service::FileSystemService;
@@ -33,7 +33,7 @@ impl DirectoryTreeTool {
         context: &FileSystemService,
     ) -> std::result::Result<CallToolResult, CallToolError> {
         let mut entry_counter: usize = 0;
-        let entries = context
+        let (entries, reached_max_depth) = context
             .directory_tree(
                 params.path,
                 params.max_depth.map(|v| v as usize),
@@ -49,8 +49,22 @@ impl DirectoryTreeTool {
         }
 
         let json_str = serde_json::to_string_pretty(&json!(entries)).map_err(CallToolError::new)?;
-        Ok(CallToolResult::text_content(vec![TextContent::from(
-            json_str,
-        )]))
+
+        // Include meta flag to denote that max depth was hit; some files and directories might be omitted
+        let meta = if reached_max_depth {
+            let mut meta = Map::new();
+            meta.insert(
+                "warning".to_string(),
+                Value::String(
+                    "Incomplete listing: subdirectories beyond the maximum depth were skipped."
+                        .to_string(),
+                ),
+            );
+            Some(meta)
+        } else {
+            None
+        };
+
+        Ok(CallToolResult::text_content(vec![TextContent::from(json_str)]).with_meta(meta))
     }
 }