fix(tui): hint mention depth cap on misses

crates/tui/src/tui/file_mention.rs

@@ -270,7 +270,10 @@ pub fn try_autocomplete_file_mention(app: &mut App) -> bool {
     let ws = workspace_for_app(app);
     let candidates = find_file_mention_completions(&ws, &partial, FILE_MENTION_COMPLETION_LIMIT);
     if candidates.is_empty() {
-        app.status_message = Some(format!("No files match @{partial}"));
+        app.status_message = Some(no_file_mention_matches_status(
+            &partial,
+            app.mention_walk_depth,
+        ));
         return true;
     }
     if candidates.len() == 1 {
@@ -297,6 +300,27 @@ pub fn try_autocomplete_file_mention(app: &mut App) -> bool {
     true
 }
 
+fn no_file_mention_matches_status(partial: &str, walk_depth: usize) -> String {
+    if path_partial_reaches_walk_depth(partial, walk_depth) {
+        format!(
+            "No files match @{partial} (mention_walk_depth={walk_depth}; use /config set mention_walk_depth 0 to search deeper)"
+        )
+    } else {
+        format!("No files match @{partial}")
+    }
+}
+
+fn path_partial_reaches_walk_depth(partial: &str, walk_depth: usize) -> bool {
+    if walk_depth == 0 {
+        return false;
+    }
+    let component_count = partial
+        .split(['/', '\\'])
+        .filter(|component| !component.is_empty())
+        .count();
+    component_count >= walk_depth
+}
+
 /// Splice a completion into the input, replacing the `@<partial>` token at
 /// `byte_start` with `@<replacement>`. Cursor moves to the end of the new
 /// token so further keystrokes extend (or escape via space) naturally.

crates/tui/src/tui/ui/tests.rs

@@ -4694,6 +4694,59 @@ fn try_autocomplete_file_mention_no_match_reports_status() {
     );
 }
 
+#[test]
+fn try_autocomplete_file_mention_no_match_mentions_depth_cap_for_path_like_partial() {
+    let tmpdir = TempDir::new().expect("tempdir");
+
+    let mut app = create_test_app();
+    app.workspace = tmpdir.path().to_path_buf();
+    app.mention_walk_depth = 6;
+    app.input = "@a/b/c/d/e/f/g/target".to_string();
+    app.cursor_position = app.input.chars().count();
+
+    assert!(try_autocomplete_file_mention(&mut app));
+    assert_eq!(
+        app.status_message.as_deref(),
+        Some(
+            "No files match @a/b/c/d/e/f/g/target (mention_walk_depth=6; use /config set mention_walk_depth 0 to search deeper)"
+        )
+    );
+}
+
+#[test]
+fn try_autocomplete_file_mention_no_match_skips_depth_hint_for_shallow_path() {
+    let tmpdir = TempDir::new().expect("tempdir");
+
+    let mut app = create_test_app();
+    app.workspace = tmpdir.path().to_path_buf();
+    app.mention_walk_depth = 6;
+    app.input = "@shallow_missing/main.rs".to_string();
+    app.cursor_position = app.input.chars().count();
+
+    assert!(try_autocomplete_file_mention(&mut app));
+    assert_eq!(
+        app.status_message.as_deref(),
+        Some("No files match @shallow_missing/main.rs")
+    );
+}
+
+#[test]
+fn try_autocomplete_file_mention_no_match_skips_depth_hint_when_unlimited() {
+    let tmpdir = TempDir::new().expect("tempdir");
+
+    let mut app = create_test_app();
+    app.workspace = tmpdir.path().to_path_buf();
+    app.mention_walk_depth = 0;
+    app.input = "@a/b/c/d/e/f/g/target".to_string();
+    app.cursor_position = app.input.chars().count();
+
+    assert!(try_autocomplete_file_mention(&mut app));
+    assert_eq!(
+        app.status_message.as_deref(),
+        Some("No files match @a/b/c/d/e/f/g/target")
+    );
+}
+
 #[test]
 fn try_autocomplete_file_mention_returns_false_outside_mention() {
     let mut app = create_test_app();