Use the main thread less on search tool (#26732)

Release Notes:

- N/A

Cargo.lock

@@ -727,6 +727,7 @@ dependencies = [
  "ui",
  "util",
  "workspace",
+ "worktree",
 ]
 
 [[package]]

crates/assistant_tools/Cargo.toml

@@ -30,6 +30,7 @@ theme.workspace = true
 ui.workspace = true
 util.workspace = true
 workspace.workspace = true
+worktree.workspace = true
 settings.workspace = true
 
 [dev-dependencies]

crates/assistant_tools/src/path_search_tool.rs

@@ -1,12 +1,13 @@
 use anyhow::{anyhow, Result};
 use assistant_tool::{ActionLog, Tool};
-use gpui::{App, Entity, Task};
+use gpui::{App, AppContext, Entity, Task};
 use language_model::LanguageModelRequestMessage;
 use project::Project;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use std::{path::PathBuf, sync::Arc};
 use util::paths::PathMatcher;
+use worktree::Snapshot;
 
 #[derive(Debug, Serialize, Deserialize, JsonSchema)]
 pub struct PathSearchToolInput {
@@ -56,11 +57,16 @@ impl Tool for PathSearchTool {
             Ok(matcher) => matcher,
             Err(err) => return Task::ready(Err(anyhow!("Invalid glob: {}", err))),
         };
+        let snapshots: Vec<Snapshot> = project
+            .read(cx)
+            .worktrees(cx)
+            .map(|worktree| worktree.read(cx).snapshot())
+            .collect();
 
+        cx.background_spawn(async move {
             let mut matches = Vec::new();
 
-        for worktree_handle in project.read(cx).worktrees(cx) {
-            let worktree = worktree_handle.read(cx);
+            for worktree in snapshots {
                 let root_name = worktree.root_name();
 
                 // Don't consider ignored entries.
@@ -77,13 +83,12 @@ impl Tool for PathSearchTool {
             }
 
             if matches.is_empty() {
-            Task::ready(Ok(format!(
-                "No paths in the project matched the glob {glob:?}"
-            )))
+                Ok(format!("No paths in the project matched the glob {glob:?}"))
             } else {
                 // Sort to group entries in the same directory together.
                 matches.sort();
-            Task::ready(Ok(matches.join("\n")))
+                Ok(matches.join("\n"))
             }
+        })
     }
 }