Add ListDirectoryTool (#26549)

Release Notes:

- N/A

crates/assistant_tools/src/assistant_tools.rs

@@ -1,4 +1,5 @@
 mod edit_files_tool;
+mod list_directory_tool;
 mod now_tool;
 mod read_file_tool;
 
@@ -6,6 +7,7 @@ use assistant_tool::ToolRegistry;
 use gpui::App;
 
 use crate::edit_files_tool::EditFilesTool;
+use crate::list_directory_tool::ListDirectoryTool;
 use crate::now_tool::NowTool;
 use crate::read_file_tool::ReadFileTool;
 
@@ -15,5 +17,6 @@ pub fn init(cx: &mut App) {
     let registry = ToolRegistry::global(cx);
     registry.register_tool(NowTool);
     registry.register_tool(ReadFileTool);
+    registry.register_tool(ListDirectoryTool);
     registry.register_tool(EditFilesTool);
 }

crates/assistant_tools/src/list_directory_tool.rs

@@ -0,0 +1,88 @@
+use anyhow::{anyhow, Result};
+use assistant_tool::Tool;
+use gpui::{App, Entity, Task};
+use language_model::LanguageModelRequestMessage;
+use project::Project;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+use std::{fmt::Write, path::Path, sync::Arc};
+
+#[derive(Debug, Serialize, Deserialize, JsonSchema)]
+pub struct ListDirectoryToolInput {
+    /// The relative path of the directory to list.
+    ///
+    /// This path should never be absolute, and the first component
+    /// of the path should always be a top-level directory in a project.
+    ///
+    /// <example>
+    /// If the project has the following top-level directories:
+    ///
+    /// - directory1
+    /// - directory2
+    ///
+    /// You can list the contents of `directory1` by using the path `directory1`.
+    /// </example>
+    ///
+    /// <example>
+    /// If the project has the following top-level directories:
+    ///
+    /// - foo
+    /// - bar
+    ///
+    /// If you wanna list contents in the directory `foo/baz`, you should use the path `foo/baz`.
+    /// </example>
+    pub path: Arc<Path>,
+}
+
+pub struct ListDirectoryTool;
+
+impl Tool for ListDirectoryTool {
+    fn name(&self) -> String {
+        "list-directory".into()
+    }
+
+    fn description(&self) -> String {
+        include_str!("./list_directory_tool/description.md").into()
+    }
+
+    fn input_schema(&self) -> serde_json::Value {
+        let schema = schemars::schema_for!(ListDirectoryToolInput);
+        serde_json::to_value(&schema).unwrap()
+    }
+
+    fn run(
+        self: Arc<Self>,
+        input: serde_json::Value,
+        _messages: &[LanguageModelRequestMessage],
+        project: Entity<Project>,
+        cx: &mut App,
+    ) -> Task<Result<String>> {
+        let input = match serde_json::from_value::<ListDirectoryToolInput>(input) {
+            Ok(input) => input,
+            Err(err) => return Task::ready(Err(anyhow!(err))),
+        };
+
+        let Some(worktree_root_name) = input.path.components().next() else {
+            return Task::ready(Err(anyhow!("Invalid path")));
+        };
+        let Some(worktree) = project
+            .read(cx)
+            .worktree_for_root_name(&worktree_root_name.as_os_str().to_string_lossy(), cx)
+        else {
+            return Task::ready(Err(anyhow!("Directory not found in the project")));
+        };
+        let path = input.path.strip_prefix(worktree_root_name).unwrap();
+        let mut output = String::new();
+        for entry in worktree.read(cx).child_entries(path) {
+            writeln!(
+                output,
+                "{}",
+                Path::new(worktree_root_name.as_os_str())
+                    .join(&entry.path)
+                    .display(),
+            )
+            .unwrap();
+        }
+        Task::ready(Ok(output))
+    }
+}

crates/assistant_tools/src/list_directory_tool/description.md

@@ -0,0 +1 @@
+Lists files and directories in a given path.

crates/assistant_tools/src/read_file_tool.rs

@@ -16,13 +16,15 @@ pub struct ReadFileToolInput {
     /// This path should never be absolute, and the first component
     /// of the path should always be a top-level directory in a project.
     ///
-    /// For example, if the project has the following top-level directories:
+    /// <example>
+    /// If the project has the following top-level directories:
     ///
     /// - directory1
     /// - directory2
     ///
     /// If you wanna access `file.txt` in `directory1`, you should use the path `directory1/file.txt`.
     /// If you wanna access `file.txt` in `directory2`, you should use the path `directory2/file.txt`.
+    /// </example>
     pub path: Arc<Path>,
 }