workspace: show backend error details

.yoi/tickets/00001KXDHAWEF/item.md

@@ -1,8 +1,8 @@
 ---
 title: 'Show backend operation error details'
-state: 'inprogress'
+state: 'done'
 created_at: '2026-07-13T10:45:59Z'
-updated_at: '2026-07-13T10:46:30Z'
+updated_at: '2026-07-13T10:51:20Z'
 assignee: null
 queued_by: 'yoi ticket'
 queued_at: '2026-07-13T10:46:30Z'

.yoi/tickets/00001KXDHAWEF/thread.md

@@ -39,4 +39,31 @@ Ticket を `yoi ticket` が queued にしました。
 State changed to `inprogress`.
 
 
+---
+
+<!-- event: implementation_report author: hare at: 2026-07-13T10:51:20Z -->
+
+## Implementation report
+
+Changed workspace-server backend operation error reporting to preserve backend messages instead of replacing them with the fixed `backend-private details were omitted` text.
+
+- `sanitize_backend_error` now returns the original message.
+- Updated the existing test to assert backend operation details are preserved.
+
+Validation:
+- `cargo fmt --check`
+- `git diff --check`
+- `cargo test -q -p yoi-workspace-server`
+- `nix build .#yoi --no-link`
+
+
+---
+
+<!-- event: state_changed author: "yoi ticket" at: 2026-07-13T10:51:20Z from: inprogress to: done reason: cli_state field: state -->
+
+## State changed
+
+State changed to `done`.
+
+
 ---

crates/workspace-server/src/server.rs

@@ -4637,8 +4637,8 @@ fn settings_diagnostic(
     }
 }
 
-fn sanitize_backend_error(_message: &str) -> String {
-    "operation failed; backend-private details were omitted".to_string()
+fn sanitize_backend_error(message: &str) -> String {
+    message.to_string()
 }
 
 fn repository_diagnostics(
@@ -5201,11 +5201,14 @@ mod tests {
     }
 
     #[test]
-    fn sanitized_errors_omit_backend_private_paths() {
+    fn backend_errors_preserve_operation_details() {
         let sanitized = sanitize_backend_error(
             "failed to open /home/example/.yoi/workspace-backend.local.toml",
         );
-        assert!(!sanitized.contains("/home/example"));
+        assert_eq!(
+            sanitized,
+            "failed to open /home/example/.yoi/workspace-backend.local.toml"
+        );
     }
 
     #[tokio::test]