diff --git a/src-tauri/src/app_error.rs b/src-tauri/src/app_error.rs
index 4e73a2f..6ab638b 100644
--- a/src-tauri/src/app_error.rs
+++ b/src-tauri/src/app_error.rs
@@ -8,6 +8,8 @@ use crate::db::error::DbError;
 pub enum AppErrorCode {
     Unknown,
     InvalidInput,
+    ConfigurationMissing,
+    ConfigurationInvalid,
     NotFound,
     AlreadyExists,
     PermissionDenied,
@@ -81,3 +83,15 @@ impl From<DbError> for AppCommandError {
         Self::db(value)
     }
 }
+
+impl From<String> for AppCommandError {
+    fn from(value: String) -> Self {
+        Self::new(AppErrorCode::Unknown, "Operation failed").with_detail(value)
+    }
+}
+
+impl From<&str> for AppCommandError {
+    fn from(value: &str) -> Self {
+        Self::from(value.to_string())
+    }
+}
diff --git a/src-tauri/src/commands/folders.rs b/src-tauri/src/commands/folders.rs
index 4fea278..54ce02f 100644
--- a/src-tauri/src/commands/folders.rs
+++ b/src-tauri/src/commands/folders.rs
@@ -148,13 +148,18 @@ fn parse_count_from_output(stdout: &[u8]) -> Option<usize> {
     String::from_utf8_lossy(stdout).trim().parse::<usize>().ok()
 }
 
-async fn get_head_hash(path: &str) -> Result<Option<String>, String> {
+fn git_command_error(operation: &str, stderr: &[u8]) -> AppCommandError {
+    let stderr = String::from_utf8_lossy(stderr).trim().to_string();
+    AppCommandError::external_command(format!("git {operation} failed"), stderr)
+}
+
+async fn get_head_hash(path: &str) -> Result<Option<String>, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["rev-parse", "HEAD"])
         .current_dir(path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
         return Ok(None);
@@ -167,17 +172,16 @@ async fn get_head_hash(path: &str) -> Result<Option<String>, String> {
     Ok(Some(head))
 }
 
-async fn count_files_in_commit(path: &str, commit: &str) -> Result<usize, String> {
+async fn count_files_in_commit(path: &str, commit: &str) -> Result<usize, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["show", "--name-only", "--pretty=format:", commit])
         .current_dir(path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git show failed: {}", stderr.trim()));
+        return Err(git_command_error("show", &output.stderr));
     }
 
     Ok(count_non_empty_lines(&String::from_utf8_lossy(
@@ -185,18 +189,21 @@ async fn count_files_in_commit(path: &str, commit: &str) -> Result<usize, String
     )))
 }
 
-async fn count_changed_files_between(path: &str, base: &str, head: &str) -> Result<usize, String> {
+async fn count_changed_files_between(
+    path: &str,
+    base: &str,
+    head: &str,
+) -> Result<usize, AppCommandError> {
     let range = format!("{}..{}", base, head);
     let output = crate::process::tokio_command("git")
         .args(["diff", "--name-only", &range])
         .current_dir(path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git diff failed: {}", stderr.trim()));
+        return Err(git_command_error("diff", &output.stderr));
     }
 
     Ok(count_non_empty_lines(&String::from_utf8_lossy(
@@ -337,8 +344,8 @@ pub async fn save_folder_opened_conversations(
 }
 
 #[tauri::command]
-pub async fn create_folder_directory(path: String) -> Result<(), String> {
-    std::fs::create_dir_all(&path).map_err(|e| e.to_string())
+pub async fn create_folder_directory(path: String) -> Result<(), AppCommandError> {
+    std::fs::create_dir_all(&path).map_err(AppCommandError::io)
 }
 
 #[tauri::command]
@@ -427,13 +434,13 @@ fn classify_git_clone_error(stderr: &str) -> AppCommandError {
 }
 
 #[tauri::command]
-pub async fn get_git_branch(path: String) -> Result<Option<String>, String> {
+pub async fn get_git_branch(path: String) -> Result<Option<String>, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["rev-parse", "--abbrev-ref", "HEAD"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
         return Ok(None);
@@ -447,23 +454,22 @@ pub async fn get_git_branch(path: String) -> Result<Option<String>, String> {
 }
 
 #[tauri::command]
-pub async fn git_init(path: String) -> Result<(), String> {
+pub async fn git_init(path: String) -> Result<(), AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["init"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git init failed: {}", stderr.trim()));
+        return Err(git_command_error("init", &output.stderr));
     }
     Ok(())
 }
 
 #[tauri::command]
-pub async fn git_pull(path: String) -> Result<GitPullResult, String> {
+pub async fn git_pull(path: String) -> Result<GitPullResult, AppCommandError> {
     let head_before = get_head_hash(&path).await?;
 
     let output = crate::process::tokio_command("git")
@@ -471,11 +477,10 @@ pub async fn git_pull(path: String) -> Result<GitPullResult, String> {
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git pull failed: {}", stderr.trim()));
+        return Err(git_command_error("pull", &output.stderr));
     }
 
     let head_after = get_head_hash(&path).await?;
@@ -491,23 +496,22 @@ pub async fn git_pull(path: String) -> Result<GitPullResult, String> {
 }
 
 #[tauri::command]
-pub async fn git_fetch(path: String) -> Result<String, String> {
+pub async fn git_fetch(path: String) -> Result<String, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["fetch", "--all"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git fetch failed: {}", stderr.trim()));
+        return Err(git_command_error("fetch --all", &output.stderr));
     }
     Ok(String::from_utf8_lossy(&output.stderr).trim().to_string())
 }
 
 #[tauri::command]
-pub async fn git_push(path: String) -> Result<GitPushResult, String> {
+pub async fn git_push(path: String) -> Result<GitPushResult, AppCommandError> {
     let pushed_commits = estimate_push_commit_count(&path).await;
 
     // Check if the current branch has an upstream configured
@@ -516,7 +520,7 @@ pub async fn git_push(path: String) -> Result<GitPushResult, String> {
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     let has_upstream = upstream_check.status.success();
 
@@ -527,7 +531,7 @@ pub async fn git_push(path: String) -> Result<GitPushResult, String> {
             .current_dir(&path)
             .output()
             .await
-            .map_err(|e| e.to_string())?;
+            .map_err(AppCommandError::io)?;
         let branch = String::from_utf8_lossy(&branch_output.stdout)
             .trim()
             .to_string();
@@ -537,19 +541,18 @@ pub async fn git_push(path: String) -> Result<GitPushResult, String> {
             .current_dir(&path)
             .output()
             .await
-            .map_err(|e| e.to_string())?
+            .map_err(AppCommandError::io)?
     } else {
         crate::process::tokio_command("git")
             .args(["push"])
             .current_dir(&path)
             .output()
             .await
-            .map_err(|e| e.to_string())?
+            .map_err(AppCommandError::io)?
     };
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git push failed: {}", stderr.trim()));
+        return Err(git_command_error("push", &output.stderr));
     }
 
     Ok(GitPushResult {
@@ -563,7 +566,7 @@ pub async fn git_new_branch(
     path: String,
     branch_name: String,
     start_point: Option<String>,
-) -> Result<(), String> {
+) -> Result<(), AppCommandError> {
     let mut args = vec!["checkout".to_string(), "-b".to_string(), branch_name];
     if let Some(start_point) = start_point {
         let trimmed = start_point.trim();
@@ -577,11 +580,10 @@ pub async fn git_new_branch(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git checkout -b failed: {}", stderr.trim()));
+        return Err(git_command_error("checkout -b", &output.stderr));
     }
     Ok(())
 }
@@ -591,7 +593,7 @@ pub async fn git_worktree_add(
     path: String,
     branch_name: String,
     worktree_path: String,
-) -> Result<(), String> {
+) -> Result<(), AppCommandError> {
     // 校验分支是否已存在
     let check = crate::process::tokio_command("git")
         .args([
@@ -602,14 +604,22 @@ pub async fn git_worktree_add(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
     if check.status.success() {
-        return Err(format!("分支 '{}' 已存在", branch_name));
+        return Err(AppCommandError::new(
+            AppErrorCode::AlreadyExists,
+            "Branch already exists",
+        )
+        .with_detail(branch_name));
     }
 
     // 校验目录是否已存在
     if std::path::Path::new(&worktree_path).exists() {
-        return Err(format!("目录 '{}' 已存在", worktree_path));
+        return Err(AppCommandError::new(
+            AppErrorCode::AlreadyExists,
+            "Worktree directory already exists",
+        )
+        .with_detail(worktree_path));
     }
 
     // 执行 git worktree add -b <branch> <path>
@@ -618,43 +628,40 @@ pub async fn git_worktree_add(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git worktree add failed: {}", stderr.trim()));
+        return Err(git_command_error("worktree add", &output.stderr));
     }
     Ok(())
 }
 
 #[tauri::command]
-pub async fn git_checkout(path: String, branch_name: String) -> Result<(), String> {
+pub async fn git_checkout(path: String, branch_name: String) -> Result<(), AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["checkout", &branch_name])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git checkout failed: {}", stderr.trim()));
+        return Err(git_command_error("checkout", &output.stderr));
     }
     Ok(())
 }
 
 #[tauri::command]
-pub async fn git_list_branches(path: String) -> Result<Vec<String>, String> {
+pub async fn git_list_branches(path: String) -> Result<Vec<String>, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["branch", "--format=%(refname:short)"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git branch failed: {}", stderr.trim()));
+        return Err(git_command_error("branch", &output.stderr));
     }
 
     let branches = String::from_utf8_lossy(&output.stdout)
@@ -666,49 +673,46 @@ pub async fn git_list_branches(path: String) -> Result<Vec<String>, String> {
 }
 
 #[tauri::command]
-pub async fn git_stash(path: String) -> Result<String, String> {
+pub async fn git_stash(path: String) -> Result<String, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["stash"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git stash failed: {}", stderr.trim()));
+        return Err(git_command_error("stash", &output.stderr));
     }
     Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
 }
 
 #[tauri::command]
-pub async fn git_stash_pop(path: String) -> Result<String, String> {
+pub async fn git_stash_pop(path: String) -> Result<String, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["stash", "pop"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git stash pop failed: {}", stderr.trim()));
+        return Err(git_command_error("stash pop", &output.stderr));
     }
     Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
 }
 
 #[tauri::command]
-pub async fn git_status(path: String) -> Result<Vec<GitStatusEntry>, String> {
+pub async fn git_status(path: String) -> Result<Vec<GitStatusEntry>, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["status", "--porcelain=v1", "-uall"])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git status failed: {}", stderr.trim()));
+        return Err(git_command_error("status", &output.stderr));
     }
 
     let entries = String::from_utf8_lossy(&output.stdout)
@@ -724,7 +728,7 @@ pub async fn git_status(path: String) -> Result<Vec<GitStatusEntry>, String> {
 }
 
 #[tauri::command]
-pub async fn git_is_tracked(path: String, file: String) -> Result<bool, String> {
+pub async fn git_is_tracked(path: String, file: String) -> Result<bool, AppCommandError> {
     let literal_file = to_git_literal_pathspec(&file);
     let output = crate::process::tokio_command("git")
         .args(["ls-files", "--error-unmatch", "--"])
@@ -732,13 +736,13 @@ pub async fn git_is_tracked(path: String, file: String) -> Result<bool, String>
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     Ok(output.status.success())
 }
 
 #[tauri::command]
-pub async fn git_diff(path: String, file: Option<String>) -> Result<String, String> {
+pub async fn git_diff(path: String, file: Option<String>) -> Result<String, AppCommandError> {
     let literal_file = file.as_deref().map(to_git_literal_pathspec);
     let mut args = vec!["diff".to_string(), "HEAD".to_string()];
     if let Some(ref f) = literal_file {
@@ -751,7 +755,7 @@ pub async fn git_diff(path: String, file: Option<String>) -> Result<String, Stri
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
         // For new repos with no HEAD, fall back to diff --cached
@@ -765,7 +769,7 @@ pub async fn git_diff(path: String, file: Option<String>) -> Result<String, Stri
             .current_dir(&path)
             .output()
             .await
-            .map_err(|e| e.to_string())?;
+            .map_err(AppCommandError::io)?;
         return Ok(String::from_utf8_lossy(&fallback.stdout).to_string());
     }
 
@@ -777,10 +781,13 @@ pub async fn git_diff_with_branch(
     path: String,
     branch: String,
     file: Option<String>,
-) -> Result<String, String> {
+) -> Result<String, AppCommandError> {
     let target_branch = branch.trim();
     if target_branch.is_empty() {
-        return Err("Branch name cannot be empty".to_string());
+        return Err(AppCommandError::new(
+            AppErrorCode::InvalidInput,
+            "Branch name cannot be empty",
+        ));
     }
 
     let literal_file = file.as_deref().map(to_git_literal_pathspec);
@@ -799,15 +806,14 @@ pub async fn git_diff_with_branch(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!(
-            "git diff {} failed: {}",
-            target_branch,
-            stderr.trim()
-        ));
+        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
+        return Err(
+            AppCommandError::external_command("git diff failed", stderr)
+                .with_detail(format!("branch={target_branch}")),
+        );
     }
 
     Ok(String::from_utf8_lossy(&output.stdout).to_string())
@@ -818,7 +824,7 @@ pub async fn git_show_diff(
     path: String,
     commit: String,
     file: Option<String>,
-) -> Result<String, String> {
+) -> Result<String, AppCommandError> {
     let literal_file = file.as_deref().map(to_git_literal_pathspec);
     let mut args = vec![
         "show".to_string(),
@@ -836,11 +842,10 @@ pub async fn git_show_diff(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git show failed: {}", stderr.trim()));
+        return Err(git_command_error("show", &output.stderr));
     }
 
     Ok(String::from_utf8_lossy(&output.stdout).to_string())
@@ -851,7 +856,7 @@ pub async fn git_show_file(
     path: String,
     file: String,
     ref_name: Option<String>,
-) -> Result<String, String> {
+) -> Result<String, AppCommandError> {
     let git_ref = ref_name.unwrap_or_else(|| "HEAD".to_string());
     let file_spec = format!("{}:{}", git_ref, file);
 
@@ -860,7 +865,7 @@ pub async fn git_show_file(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
         // File doesn't exist at this ref (e.g. new/untracked file) — return empty
@@ -869,7 +874,11 @@ pub async fn git_show_file(
 
     let bytes = &output.stdout;
     if bytes.iter().take(2048).any(|b| *b == 0) {
-        return Err("Binary files are not supported".to_string());
+        return Err(AppCommandError::new(
+            AppErrorCode::InvalidInput,
+            "Binary files are not supported",
+        )
+        .with_detail(file_spec));
     }
 
     Ok(String::from_utf8_lossy(bytes).to_string())
@@ -882,7 +891,7 @@ pub async fn git_commit(
     path: String,
     message: String,
     files: Vec<String>,
-) -> Result<GitCommitResult, String> {
+) -> Result<GitCommitResult, AppCommandError> {
     // Stage selected files
     let mut add_args = vec!["add".to_string(), "--".to_string()];
     add_args.extend(files.iter().map(|file| to_git_literal_pathspec(file)));
@@ -892,11 +901,10 @@ pub async fn git_commit(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !add_output.status.success() {
-        let stderr = String::from_utf8_lossy(&add_output.stderr);
-        return Err(format!("git add failed: {}", stderr.trim()));
+        return Err(git_command_error("add", &add_output.stderr));
     }
 
     // Commit
@@ -905,11 +913,10 @@ pub async fn git_commit(
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !commit_output.status.success() {
-        let stderr = String::from_utf8_lossy(&commit_output.stderr);
-        return Err(format!("git commit failed: {}", stderr.trim()));
+        return Err(git_command_error("commit", &commit_output.stderr));
     }
 
     let committed_files = count_files_in_commit(&path, "HEAD")
@@ -934,10 +941,13 @@ pub async fn git_commit(
 }
 
 #[tauri::command]
-pub async fn git_rollback_file(path: String, file: String) -> Result<(), String> {
+pub async fn git_rollback_file(path: String, file: String) -> Result<(), AppCommandError> {
     let target = file.trim();
     if target.is_empty() {
-        return Err("File path cannot be empty".to_string());
+        return Err(AppCommandError::new(
+            AppErrorCode::InvalidInput,
+            "File path cannot be empty",
+        ));
     }
 
     let literal_file = to_git_literal_pathspec(target);
@@ -953,7 +963,7 @@ pub async fn git_rollback_file(path: String, file: String) -> Result<(), String>
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if restore_output.status.success() {
         return Ok(());
@@ -969,7 +979,10 @@ pub async fn git_rollback_file(path: String, file: String) -> Result<(), String>
         && !restore_stderr_lower.contains("did you mean");
 
     if supports_restore {
-        return Err(format!("git restore failed: {}", restore_stderr));
+        return Err(AppCommandError::external_command(
+            "git restore failed",
+            restore_stderr,
+        ));
     }
 
     let _ = crate::process::tokio_command("git")
@@ -977,25 +990,24 @@ pub async fn git_rollback_file(path: String, file: String) -> Result<(), String>
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     let checkout_output = crate::process::tokio_command("git")
         .args(["checkout", "--", &literal_file])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !checkout_output.status.success() {
-        let checkout_stderr = String::from_utf8_lossy(&checkout_output.stderr);
-        return Err(format!("git checkout failed: {}", checkout_stderr.trim()));
+        return Err(git_command_error("checkout --", &checkout_output.stderr));
     }
 
     Ok(())
 }
 
 #[tauri::command]
-pub async fn git_add_files(path: String, files: Vec<String>) -> Result<(), String> {
+pub async fn git_add_files(path: String, files: Vec<String>) -> Result<(), AppCommandError> {
     if files.is_empty() {
         return Ok(());
     }
@@ -1008,18 +1020,17 @@ pub async fn git_add_files(path: String, files: Vec<String>) -> Result<(), Strin
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git add failed: {}", stderr.trim()));
+        return Err(git_command_error("add", &output.stderr));
     }
 
     Ok(())
 }
 
 #[tauri::command]
-pub async fn git_list_all_branches(path: String) -> Result<GitBranchList, String> {
+pub async fn git_list_all_branches(path: String) -> Result<GitBranchList, AppCommandError> {
     let local_fut = crate::process::tokio_command("git")
         .args(["branch", "--format=%(refname:short)"])
         .current_dir(&path)
@@ -1037,10 +1048,9 @@ pub async fn git_list_all_branches(path: String) -> Result<GitBranchList, String
 
     let (local_output, remote_output, wt_output) = tokio::join!(local_fut, remote_fut, wt_fut);
 
-    let local_output = local_output.map_err(|e| e.to_string())?;
+    let local_output = local_output.map_err(AppCommandError::io)?;
     if !local_output.status.success() {
-        let stderr = String::from_utf8_lossy(&local_output.stderr);
-        return Err(format!("git branch failed: {}", stderr.trim()));
+        return Err(git_command_error("branch", &local_output.stderr));
     }
 
     let local: Vec<String> = String::from_utf8_lossy(&local_output.stdout)
@@ -1094,14 +1104,14 @@ pub async fn git_list_all_branches(path: String) -> Result<GitBranchList, String
 }
 
 #[tauri::command]
-pub async fn git_merge(path: String, branch_name: String) -> Result<GitMergeResult, String> {
+pub async fn git_merge(path: String, branch_name: String) -> Result<GitMergeResult, AppCommandError> {
     // Count commits to be merged before performing merge
     let count_output = crate::process::tokio_command("git")
         .args(["rev-list", "--count", &format!("HEAD..{}", branch_name)])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     let merged_commits = if count_output.status.success() {
         String::from_utf8_lossy(&count_output.stdout)
@@ -1117,27 +1127,25 @@ pub async fn git_merge(path: String, branch_name: String) -> Result<GitMergeResu
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git merge failed: {}", stderr.trim()));
+        return Err(git_command_error("merge", &output.stderr));
     }
     Ok(GitMergeResult { merged_commits })
 }
 
 #[tauri::command]
-pub async fn git_rebase(path: String, branch_name: String) -> Result<String, String> {
+pub async fn git_rebase(path: String, branch_name: String) -> Result<String, AppCommandError> {
     let output = crate::process::tokio_command("git")
         .args(["rebase", &branch_name])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git rebase failed: {}", stderr.trim()));
+        return Err(git_command_error("rebase", &output.stderr));
     }
     Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
 }
@@ -1147,18 +1155,17 @@ pub async fn git_delete_branch(
     path: String,
     branch_name: String,
     force: bool,
-) -> Result<String, String> {
+) -> Result<String, AppCommandError> {
     let flag = if force { "-D" } else { "-d" };
     let output = crate::process::tokio_command("git")
         .args(["branch", flag, &branch_name])
         .current_dir(&path)
         .output()
         .await
-        .map_err(|e| e.to_string())?;
+        .map_err(AppCommandError::io)?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(format!("git branch {} failed: {}", flag, stderr.trim()));
+        return Err(git_command_error(&format!("branch {flag}"), &output.stderr));
     }
     Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
 }
diff --git a/src-tauri/src/commands/system_settings.rs b/src-tauri/src/commands/system_settings.rs
index e9ef45c..90d8c88 100644
--- a/src-tauri/src/commands/system_settings.rs
+++ b/src-tauri/src/commands/system_settings.rs
@@ -34,13 +34,13 @@ fn normalize_proxy_settings(
         .filter(|value| !value.is_empty())
         .ok_or_else(|| {
             AppCommandError::new(
-                AppErrorCode::InvalidInput,
+                AppErrorCode::ConfigurationMissing,
                 "Proxy URL is required when proxy is enabled",
             )
         })?;
 
     reqwest::Proxy::all(proxy_url).map_err(|e| {
-        AppCommandError::new(AppErrorCode::InvalidInput, "Invalid proxy URL")
+        AppCommandError::new(AppErrorCode::ConfigurationInvalid, "Invalid proxy URL")
             .with_detail(e.to_string())
     })?;
 
@@ -63,7 +63,7 @@ pub(crate) async fn load_system_proxy_settings(
 
     let parsed = serde_json::from_str::<SystemProxySettings>(&raw).map_err(|e| {
         AppCommandError::new(
-            AppErrorCode::InvalidInput,
+            AppErrorCode::ConfigurationInvalid,
             "Failed to parse stored proxy settings",
         )
         .with_detail(e.to_string())
@@ -84,7 +84,7 @@ pub(crate) async fn load_system_language_settings(
 
     serde_json::from_str::<SystemLanguageSettings>(&raw).map_err(|e| {
         AppCommandError::new(
-            AppErrorCode::InvalidInput,
+            AppErrorCode::ConfigurationInvalid,
             "Failed to parse stored language settings",
         )
         .with_detail(e.to_string())
@@ -116,13 +116,7 @@ pub async fn update_system_proxy_settings(
         .await
         .map_err(AppCommandError::from)?;
 
-    proxy::apply_system_proxy_settings(&normalized).map_err(|e| {
-        AppCommandError::new(
-            AppErrorCode::ExternalCommandFailed,
-            "Failed to apply system proxy settings",
-        )
-        .with_detail(e)
-    })?;
+    proxy::apply_system_proxy_settings(&normalized)?;
     Ok(normalized)
 }
 
diff --git a/src-tauri/src/network/proxy.rs b/src-tauri/src/network/proxy.rs
index 204bac5..1d33e64 100644
--- a/src-tauri/src/network/proxy.rs
+++ b/src-tauri/src/network/proxy.rs
@@ -1,3 +1,4 @@
+use crate::app_error::{AppCommandError, AppErrorCode};
 use crate::models::SystemProxySettings;
 
 const PROXY_ENV_KEYS: [&str; 6] = [
@@ -9,14 +10,19 @@ const PROXY_ENV_KEYS: [&str; 6] = [
     "all_proxy",
 ];
 
-pub fn apply_system_proxy_settings(settings: &SystemProxySettings) -> Result<(), String> {
+pub fn apply_system_proxy_settings(settings: &SystemProxySettings) -> Result<(), AppCommandError> {
     if settings.enabled {
         let proxy_url = settings
             .proxy_url
             .as_deref()
             .map(str::trim)
             .filter(|value| !value.is_empty())
-            .ok_or_else(|| "proxy url is required when proxy is enabled".to_string())?;
+            .ok_or_else(|| {
+                AppCommandError::new(
+                    AppErrorCode::ConfigurationMissing,
+                    "Proxy URL is required when proxy is enabled",
+                )
+            })?;
 
         for key in PROXY_ENV_KEYS {
             unsafe {
diff --git a/src/components/chat/live-message-block.tsx b/src/components/chat/live-message-block.tsx
index fed2396..7fc580d 100644
--- a/src/components/chat/live-message-block.tsx
+++ b/src/components/chat/live-message-block.tsx
@@ -15,8 +15,16 @@ export const LiveMessageBlock = memo(function LiveMessageBlock({
   message,
 }: LiveMessageBlockProps) {
   const t = useTranslations("Folder.chat.liveMessageBlock")
+  const sharedT = useTranslations("Folder.chat.shared")
   const hasContent = message.content.length > 0
-  const adapted = useMemo(() => adaptLiveMessageFromAcp(message), [message])
+  const adapted = useMemo(
+    () =>
+      adaptLiveMessageFromAcp(message, {
+        toolCallFailedText: sharedT("toolCallFailed"),
+        planUpdatedText: sharedT("planUpdated"),
+      }),
+    [message, sharedT]
+  )
 
   return (
     <Message from="assistant">
diff --git a/src/components/chat/welcome-input-panel.tsx b/src/components/chat/welcome-input-panel.tsx
index c96cff2..fe7d020 100644
--- a/src/components/chat/welcome-input-panel.tsx
+++ b/src/components/chat/welcome-input-panel.tsx
@@ -87,6 +87,8 @@ export function WelcomeInputPanel({
   isActive = true,
 }: WelcomeInputPanelProps) {
   const t = useTranslations("Folder.chat.welcomeInputPanel")
+  const tabT = useTranslations("Folder.tabContext")
+  const sharedT = useTranslations("Folder.chat.shared")
   const fallbackContextId = useMemo(() => crypto.randomUUID(), [])
   const contextKey = tabId ?? `new-${fallbackContextId}`
 
@@ -159,7 +161,10 @@ export function WelcomeInputPanel({
           const detail = await getFolderConversation(conversationId)
           if (refreshSeq !== statsRefreshSeqRef.current) return
 
-          const messages = adaptMessageTurns(detail.turns)
+          const messages = adaptMessageTurns(detail.turns, {
+            attachedResources: sharedT("attachedResources"),
+            toolCallFailed: sharedT("toolCallFailed"),
+          })
           const stats = detail.session_stats ?? null
           latestMessages = messages
           latestStats = stats
@@ -196,7 +201,7 @@ export function WelcomeInputPanel({
         applySessionStats(latestStats)
       }
     },
-    [applySessionStats, hasAssistantUsage, hasTokenStats]
+    [applySessionStats, hasAssistantUsage, hasTokenStats, sharedT]
   )
 
   useEffect(() => {
@@ -354,6 +359,8 @@ export function WelcomeInputPanel({
       if (conn.liveMessage && conn.liveMessage.content.length > 0) {
         const adapted = adaptLiveMessageFromAcp(conn.liveMessage, {
           isLiveStreaming: false,
+          toolCallFailedText: sharedT("toolCallFailed"),
+          planUpdatedText: sharedT("planUpdated"),
         })
 
         setHistory((h) => [...h, adapted])
@@ -376,7 +383,7 @@ export function WelcomeInputPanel({
       )
     }
     // eslint-disable-next-line react-hooks/exhaustive-deps -- conn.liveMessage, lifecycleSend intentionally omitted: effect only fires on status transitions
-  }, [connStatus, refreshConversations, refreshConversationFromDb])
+  }, [connStatus, refreshConversations, refreshConversationFromDb, sharedT])
 
   // When connection becomes "connected" and we have a pending prompt, send it
   useEffect(() => {
@@ -394,7 +401,7 @@ export function WelcomeInputPanel({
     const tid = tabIdRef.current
     const convId = dbConvIdRef.current
     const agent = selectedAgentRef.current
-    const title = convTitleRef.current || "Untitled"
+    const title = convTitleRef.current || tabT("untitledConversation")
     const canonicalContextKey = `conv-${agent}-${convId}`
 
     // Keep in-flight stream/state attached when this new-conversation view
@@ -410,6 +417,7 @@ export function WelcomeInputPanel({
     refreshConversations,
     migrateContextKey,
     contextKey,
+    tabT,
   ])
 
   // Update conversation status on disconnect/error + promote tab
@@ -466,11 +474,17 @@ export function WelcomeInputPanel({
   // Welcome phase: submit first message.
   const handleWelcomeSend = useCallback(
     (draft: PromptDraft, selectedModeId?: string | null) => {
-      const displayText = getPromptDraftDisplayText(draft)
+      const displayText = getPromptDraftDisplayText(
+        draft,
+        sharedT("attachedResources")
+      )
       const userMsg: AdaptedMessage = {
         id: crypto.randomUUID(),
         role: "user",
-        content: buildUserMessageTextPartsFromDraft(draft),
+        content: buildUserMessageTextPartsFromDraft(
+          draft,
+          sharedT("attachedResources")
+        ),
         userResources: extractUserResourcesFromDraft(draft),
         timestamp: new Date().toISOString(),
       }
@@ -536,6 +550,7 @@ export function WelcomeInputPanel({
       trySaveExternalId,
       applySessionStats,
       newConversationDraftStorageKey,
+      sharedT,
     ]
   )
 
@@ -545,7 +560,10 @@ export function WelcomeInputPanel({
       const userMsg: AdaptedMessage = {
         id: crypto.randomUUID(),
         role: "user",
-        content: buildUserMessageTextPartsFromDraft(draft),
+        content: buildUserMessageTextPartsFromDraft(
+          draft,
+          sharedT("attachedResources")
+        ),
         userResources: extractUserResourcesFromDraft(draft),
         timestamp: new Date().toISOString(),
       }
@@ -562,7 +580,7 @@ export function WelcomeInputPanel({
         statusUpdatedRef.current = false
       }
     },
-    [lifecycleSend, refreshConversations]
+    [lifecycleSend, refreshConversations, sharedT]
   )
 
   const handleOpenAgentsSettings = useCallback(() => {
diff --git a/src/components/conversations/conversation-detail-panel.tsx b/src/components/conversations/conversation-detail-panel.tsx
index bf85234..67d2452 100644
--- a/src/components/conversations/conversation-detail-panel.tsx
+++ b/src/components/conversations/conversation-detail-panel.tsx
@@ -43,6 +43,7 @@ const ExistingConversationView = memo(function ExistingConversationView({
   reloadSignal,
 }: ExistingConversationViewProps) {
   const t = useTranslations("Folder.conversation")
+  const sharedT = useTranslations("Folder.chat.shared")
   const { refreshConversations, folder } = useFolderContext()
   const contextKey = `conv-${agentType}-${conversationId}`
 
@@ -114,7 +115,10 @@ const ExistingConversationView = memo(function ExistingConversationView({
         {
           id: `pending-${Date.now()}`,
           role: "user",
-          content: buildUserMessageTextPartsFromDraft(draft),
+          content: buildUserMessageTextPartsFromDraft(
+            draft,
+            sharedT("attachedResources")
+          ),
           userResources: extractUserResourcesFromDraft(draft),
           timestamp: new Date().toISOString(),
         },
@@ -125,7 +129,7 @@ const ExistingConversationView = memo(function ExistingConversationView({
       statusUpdatedRef.current = false
       handleSend(draft, selectedModeId)
     },
-    [conversationId, handleSend, refreshConversations]
+    [conversationId, handleSend, refreshConversations, sharedT]
   )
 
   // Update status on turn complete
diff --git a/src/components/message/content-parts-renderer.tsx b/src/components/message/content-parts-renderer.tsx
index c4bca38..5b1a465 100644
--- a/src/components/message/content-parts-renderer.tsx
+++ b/src/components/message/content-parts-renderer.tsx
@@ -1660,6 +1660,7 @@ const CODE_FIELDS = new Set([
 const HIDDEN_FIELDS = new Set(["dangerouslyDisableSandbox"])
 
 function GenericToolInput({ input }: { input: string }) {
+  const t = useTranslations("Folder.chat.contentParts")
   const parsed = tryParseJson(input)
 
   if (!parsed) {
@@ -1677,6 +1678,9 @@ function GenericToolInput({ input }: { input: string }) {
   return (
     <div className="space-y-3">
       {entries.map(([key, value]) => {
+        const labelKey = fieldLabelKey(key)
+        const label = labelKey ? t(labelKey) : key
+
         if (CODE_FIELDS.has(key) && typeof value === "string") {
           const lang =
             key === "command"
@@ -1685,7 +1689,7 @@ function GenericToolInput({ input }: { input: string }) {
                 ? ("log" as const)
                 : ("log" as const)
           return (
-            <FieldBlock key={key} label={fieldLabel(key)}>
+            <FieldBlock key={key} label={label}>
               <CodeBlock code={value} language={lang} />
             </FieldBlock>
           )
@@ -1694,29 +1698,23 @@ function GenericToolInput({ input }: { input: string }) {
         if (typeof value === "string") {
           if (value.length > 200) {
             return (
-              <FieldBlock key={key} label={fieldLabel(key)}>
+              <FieldBlock key={key} label={label}>
                 <pre className="whitespace-pre-wrap break-all rounded-md bg-muted/50 p-3 text-xs">
                   {value}
                 </pre>
               </FieldBlock>
             )
           }
-          return <FieldInline key={key} label={fieldLabel(key)} value={value} />
+          return <FieldInline key={key} label={label} value={value} />
         }
 
         if (typeof value === "number" || typeof value === "boolean") {
-          return (
-            <FieldInline
-              key={key}
-              label={fieldLabel(key)}
-              value={String(value)}
-            />
-          )
+          return <FieldInline key={key} label={label} value={String(value)} />
         }
 
         if (value !== null && value !== undefined) {
           return (
-            <FieldBlock key={key} label={fieldLabel(key)}>
+            <FieldBlock key={key} label={label}>
               <CodeBlock
                 code={JSON.stringify(value, null, 2)}
                 language="json"
@@ -1836,41 +1834,45 @@ function FieldBlock({
   )
 }
 
-function fieldLabel(key: string): string {
-  const map: Record<string, string> = {
-    file_path: "File",
-    notebook_path: "Notebook",
-    command: "Command",
-    cmd: "Command",
-    old_string: "Old",
-    new_string: "New",
-    pattern: "Pattern",
-    path: "Path",
-    query: "Query",
-    url: "URL",
-    description: "Description",
-    content: "Content",
-    new_source: "Source",
-    prompt: "Prompt",
-    subject: "Subject",
-    taskId: "Task ID",
-    status: "Status",
-    skill: "Skill",
-    args: "Args",
-    offset: "Offset",
-    limit: "Limit",
-    glob: "Glob",
-    type: "Type",
-    output_mode: "Output",
-    replace_all: "Replace All",
-    language: "Language",
-    timeout: "Timeout",
-    run_in_background: "Background",
-    subagent_type: "Agent Type",
-    libraryName: "Library",
-    libraryId: "Library ID",
-  }
-  return map[key] ?? key
+const FIELD_LABEL_KEYS = {
+  file_path: "field.file",
+  notebook_path: "field.notebook",
+  command: "field.command",
+  cmd: "field.command",
+  old_string: "field.old",
+  new_string: "field.new",
+  pattern: "field.pattern",
+  path: "field.path",
+  query: "field.query",
+  url: "field.url",
+  description: "field.description",
+  content: "field.content",
+  new_source: "field.source",
+  prompt: "field.prompt",
+  subject: "field.subject",
+  taskId: "field.taskId",
+  status: "field.status",
+  skill: "field.skill",
+  args: "field.args",
+  offset: "field.offset",
+  limit: "field.limit",
+  glob: "field.glob",
+  type: "field.type",
+  output_mode: "field.output",
+  replace_all: "field.replaceAll",
+  language: "field.language",
+  timeout: "field.timeout",
+  run_in_background: "field.background",
+  subagent_type: "field.agentType",
+  libraryName: "field.library",
+  libraryId: "field.libraryId",
+} as const
+
+function fieldLabelKey(
+  key: string
+): (typeof FIELD_LABEL_KEYS)[keyof typeof FIELD_LABEL_KEYS] | null {
+  const translationKey = FIELD_LABEL_KEYS[key as keyof typeof FIELD_LABEL_KEYS]
+  return translationKey ?? null
 }
 
 function commandOutputFromJsonString(output: string): string | null {
diff --git a/src/components/message/message-list-view.tsx b/src/components/message/message-list-view.tsx
index aa6b99c..a4a5473 100644
--- a/src/components/message/message-list-view.tsx
+++ b/src/components/message/message-list-view.tsx
@@ -169,6 +169,7 @@ export function MessageListView({
   isActive = true,
 }: MessageListViewProps) {
   const t = useTranslations("Folder.chat.messageList")
+  const sharedT = useTranslations("Folder.chat.shared")
   const { detail, loading, error, refetch } = useDbMessageDetail(conversationId)
   const turnCount = detail?.turns.length ?? 0
 
@@ -213,8 +214,14 @@ export function MessageListView({
   const shouldUseSmoothResize = !(isActive && !loading && detail)
 
   const messages = useMemo(
-    () => (detail ? adaptMessageTurns(detail.turns) : []),
-    [detail]
+    () =>
+      detail
+        ? adaptMessageTurns(detail.turns, {
+            attachedResources: sharedT("attachedResources"),
+            toolCallFailed: sharedT("toolCallFailed"),
+          })
+        : [],
+    [detail, sharedT]
   )
 
   const groups = useMemo(() => groupAdaptedMessages(messages), [messages])
@@ -234,15 +241,17 @@ export function MessageListView({
   )
   const resolvedGroups = useMemo(
     () =>
-      groups.map((group) => resolveMessageGroup(group, t("attachedResources"))),
-    [groups, t]
+      groups.map((group) =>
+        resolveMessageGroup(group, sharedT("attachedResources"))
+      ),
+    [groups, sharedT]
   )
   const resolvedPendingGroups = useMemo(
     () =>
       pendingGroups.map((group) =>
-        resolveMessageGroup(group, t("attachedResources"))
+        resolveMessageGroup(group, sharedT("attachedResources"))
       ),
-    [pendingGroups, t]
+    [pendingGroups, sharedT]
   )
 
   const showLiveMessage = Boolean(
diff --git a/src/components/welcome/error-utils.ts b/src/components/welcome/error-utils.ts
index 1a4f9a5..4017fec 100644
--- a/src/components/welcome/error-utils.ts
+++ b/src/components/welcome/error-utils.ts
@@ -33,6 +33,8 @@ function stripClonePrefix(message: string): string {
 function mapCommonCodeToKey(code: string): WelcomeErrorKey {
   switch (code) {
     case "invalid_input":
+    case "configuration_missing":
+    case "configuration_invalid":
       return "errors.invalidInput"
     case "not_found":
       return "errors.notFound"
diff --git a/src/contexts/acp-connections-context.tsx b/src/contexts/acp-connections-context.tsx
index a048281..a4f6aff 100644
--- a/src/contexts/acp-connections-context.tsx
+++ b/src/contexts/acp-connections-context.tsx
@@ -124,6 +124,8 @@ type Action =
       contextKey: string
       tool_call_id: string
       title: string | null
+      fallback_title: string
+      fallback_kind: string
       status: string | null
       content: string | null
       raw_input: string | null
@@ -135,6 +137,8 @@ type Action =
       contextKey: string
       request_id: string
       tool_call: unknown
+      fallback_title: string
+      fallback_kind: string
       options: PermissionOptionInfo[]
     }
   | { type: "PERMISSION_CLEARED"; contextKey: string }
@@ -216,28 +220,28 @@ function serializePermissionToolCall(toolCall: unknown): string | null {
   }
 }
 
-function extractPermissionToolTitle(toolCall: unknown): string {
+function extractPermissionToolTitle(toolCall: unknown): string | null {
   const record = asRecord(toolCall)
-  if (!record) return "Tool"
+  if (!record) return null
   const candidates = [record.title, record.tool_name, record.name, record.type]
   for (const candidate of candidates) {
     if (typeof candidate === "string" && candidate.trim().length > 0) {
       return candidate
     }
   }
-  return "Tool"
+  return null
 }
 
-function extractPermissionToolKind(toolCall: unknown): string {
+function extractPermissionToolKind(toolCall: unknown): string | null {
   const record = asRecord(toolCall)
-  if (!record) return "tool"
+  if (!record) return null
   const candidates = [record.kind, record.tool_name, record.name, record.type]
   for (const candidate of candidates) {
     if (typeof candidate === "string" && candidate.trim().length > 0) {
       return candidate
     }
   }
-  return "tool"
+  return null
 }
 
 function sameModes(
@@ -572,8 +576,8 @@ function connectionsReducer(
             type: "tool_call",
             info: {
               tool_call_id: action.tool_call_id,
-              title: action.title ?? "Tool",
-              kind: "tool",
+              title: action.title ?? action.fallback_title,
+              kind: action.fallback_kind,
               status:
                 action.status ??
                 (normalizedRawOutput ? "in_progress" : "pending"),
@@ -665,8 +669,12 @@ function connectionsReducer(
                 type: "tool_call",
                 info: {
                   tool_call_id: permissionCallId,
-                  title: extractPermissionToolTitle(action.tool_call),
-                  kind: extractPermissionToolKind(action.tool_call),
+                  title:
+                    extractPermissionToolTitle(action.tool_call) ??
+                    action.fallback_title,
+                  kind:
+                    extractPermissionToolKind(action.tool_call) ??
+                    action.fallback_kind,
                   status: "pending",
                   content: null,
                   raw_input: permissionToolInput,
@@ -1247,6 +1255,8 @@ export function AcpConnectionsProvider({ children }: { children: ReactNode }) {
             contextKey,
             tool_call_id: e.tool_call_id,
             title: e.title,
+            fallback_title: t("toolFallbackTitle"),
+            fallback_kind: "tool",
             status: e.status,
             content: e.content,
             raw_input: e.raw_input,
@@ -1261,6 +1271,8 @@ export function AcpConnectionsProvider({ children }: { children: ReactNode }) {
             contextKey,
             request_id: e.request_id,
             tool_call: e.tool_call,
+            fallback_title: t("toolFallbackTitle"),
+            fallback_kind: "tool",
             options: e.options,
           })
           break
@@ -1322,7 +1334,7 @@ export function AcpConnectionsProvider({ children }: { children: ReactNode }) {
         case "error":
           flushStreamingQueue()
           dispatch({ type: "ERROR", contextKey, message: e.message })
-          pushAlertRef.current("error", "Agent 错误", e.message)
+          pushAlertRef.current("error", t("eventErrorTitle"), e.message)
           break
         case "available_commands":
           flushStreamingQueue()
@@ -1334,7 +1346,7 @@ export function AcpConnectionsProvider({ children }: { children: ReactNode }) {
           break
       }
     },
-    [dispatch, enqueueStreamingAction, flushStreamingQueue]
+    [dispatch, enqueueStreamingAction, flushStreamingQueue, t]
   )
 
   // Single global event listener
diff --git a/src/hooks/use-connection-lifecycle.ts b/src/hooks/use-connection-lifecycle.ts
index e3b1dec..36a4332 100644
--- a/src/hooks/use-connection-lifecycle.ts
+++ b/src/hooks/use-connection-lifecycle.ts
@@ -50,6 +50,7 @@ export function useConnectionLifecycle({
   sessionId,
 }: UseConnectionLifecycleOptions): UseConnectionLifecycleReturn {
   const t = useTranslations("Folder.chat.connectionLifecycle")
+  const sharedT = useTranslations("Folder.chat.shared")
   const { setActiveKey, touchActivity } = useAcpActions()
   const { addTask, updateTask, removeTask } = useTaskContext()
   const conn = useConnection(contextKey)
@@ -312,7 +313,10 @@ export function useConnectionLifecycle({
   const handleSend = useCallback(
     (draft: PromptDraft, modeId?: string | null) => {
       touchActivity(contextKey)
-      setPendingPromptText(contextKey, getPromptDraftDisplayText(draft))
+      setPendingPromptText(
+        contextKey,
+        getPromptDraftDisplayText(draft, sharedT("attachedResources"))
+      )
       void (async () => {
         const currentModeId = modeIdRef.current
         if (modeId && modeId !== currentModeId) {
@@ -326,7 +330,7 @@ export function useConnectionLifecycle({
         console.error("[ConnLifecycle] sendPrompt:", e)
       )
     },
-    [connSetMode, sendPrompt, contextKey, touchActivity]
+    [connSetMode, sendPrompt, contextKey, touchActivity, sharedT]
   )
 
   const handleCancel = useCallback(() => {
diff --git a/src/i18n/messages/en.json b/src/i18n/messages/en.json
index 2e21121..d4604ba 100644
--- a/src/i18n/messages/en.json
+++ b/src/i18n/messages/en.json
@@ -1079,7 +1079,9 @@
         "preflightCheckFailedDefault": "Preflight checks failed. Check Agent settings.",
         "preflightFailedTitle": "{agent} preflight failed",
         "autoLinkPreflightFailed": "Auto-link preflight failed: {message}",
-        "connectFailedTitle": "{agent} connection failed"
+        "connectFailedTitle": "{agent} connection failed",
+        "toolFallbackTitle": "Tool",
+        "eventErrorTitle": "Agent Error"
       },
       "connectionLifecycle": {
         "tasks": {
@@ -1092,6 +1094,11 @@
           "connectionFailed": "Connection failed"
         }
       },
+      "shared": {
+        "attachedResources": "Attached resources",
+        "toolCallFailed": "Tool call failed",
+        "planUpdated": "Plan updated"
+      },
       "messageThread": {
         "emptyTitle": "No messages yet",
         "emptyDescription": "Start a conversation to see messages here"
@@ -1222,6 +1229,38 @@
         "subjectLabel": "Subject",
         "taskLabel": "Task",
         "nameLabel": "Name:",
+        "field": {
+          "file": "File",
+          "notebook": "Notebook",
+          "command": "Command",
+          "old": "Old",
+          "new": "New",
+          "pattern": "Pattern",
+          "path": "Path",
+          "query": "Query",
+          "url": "URL",
+          "description": "Description",
+          "content": "Content",
+          "source": "Source",
+          "prompt": "Prompt",
+          "subject": "Subject",
+          "taskId": "Task ID",
+          "status": "Status",
+          "skill": "Skill",
+          "args": "Args",
+          "offset": "Offset",
+          "limit": "Limit",
+          "glob": "Glob",
+          "type": "Type",
+          "output": "Output",
+          "replaceAll": "Replace All",
+          "language": "Language",
+          "timeout": "Timeout",
+          "background": "Background",
+          "agentType": "Agent Type",
+          "library": "Library",
+          "libraryId": "Library ID"
+        },
         "title": {
           "edit": "Edit",
           "command": "Command",
diff --git a/src/i18n/messages/zh-CN.json b/src/i18n/messages/zh-CN.json
index 4dfc23e..a9f40b6 100644
--- a/src/i18n/messages/zh-CN.json
+++ b/src/i18n/messages/zh-CN.json
@@ -1079,7 +1079,9 @@
         "preflightCheckFailedDefault": "预检查未通过，请检查 Agent 配置。",
         "preflightFailedTitle": "{agent} 预检查失败",
         "autoLinkPreflightFailed": "自动链接预检查失败：{message}",
-        "connectFailedTitle": "{agent} 连接失败"
+        "connectFailedTitle": "{agent} 连接失败",
+        "toolFallbackTitle": "工具",
+        "eventErrorTitle": "Agent 错误"
       },
       "connectionLifecycle": {
         "tasks": {
@@ -1092,6 +1094,11 @@
           "connectionFailed": "连接失败"
         }
       },
+      "shared": {
+        "attachedResources": "附加资源",
+        "toolCallFailed": "工具调用失败",
+        "planUpdated": "计划已更新"
+      },
       "messageThread": {
         "emptyTitle": "暂无消息",
         "emptyDescription": "开始一个会话后，消息会显示在这里"
@@ -1222,6 +1229,38 @@
         "subjectLabel": "主题",
         "taskLabel": "任务",
         "nameLabel": "名称：",
+        "field": {
+          "file": "文件",
+          "notebook": "Notebook",
+          "command": "命令",
+          "old": "旧内容",
+          "new": "新内容",
+          "pattern": "模式",
+          "path": "路径",
+          "query": "查询",
+          "url": "URL",
+          "description": "描述",
+          "content": "内容",
+          "source": "源内容",
+          "prompt": "提示词",
+          "subject": "主题",
+          "taskId": "任务 ID",
+          "status": "状态",
+          "skill": "Skill",
+          "args": "参数",
+          "offset": "偏移",
+          "limit": "限制",
+          "glob": "Glob",
+          "type": "类型",
+          "output": "输出",
+          "replaceAll": "全部替换",
+          "language": "语言",
+          "timeout": "超时",
+          "background": "后台",
+          "agentType": "Agent 类型",
+          "library": "库",
+          "libraryId": "库 ID"
+        },
         "title": {
           "edit": "编辑",
           "command": "命令",
diff --git a/src/i18n/messages/zh-TW.json b/src/i18n/messages/zh-TW.json
index 092eb65..53c6429 100644
--- a/src/i18n/messages/zh-TW.json
+++ b/src/i18n/messages/zh-TW.json
@@ -1079,7 +1079,9 @@
         "preflightCheckFailedDefault": "預檢查未通過，請檢查 Agent 設定。",
         "preflightFailedTitle": "{agent} 預檢查失敗",
         "autoLinkPreflightFailed": "自動連結預檢查失敗：{message}",
-        "connectFailedTitle": "{agent} 連線失敗"
+        "connectFailedTitle": "{agent} 連線失敗",
+        "toolFallbackTitle": "工具",
+        "eventErrorTitle": "Agent 錯誤"
       },
       "connectionLifecycle": {
         "tasks": {
@@ -1092,6 +1094,11 @@
           "connectionFailed": "連線失敗"
         }
       },
+      "shared": {
+        "attachedResources": "附加資源",
+        "toolCallFailed": "工具呼叫失敗",
+        "planUpdated": "計畫已更新"
+      },
       "messageThread": {
         "emptyTitle": "暫無訊息",
         "emptyDescription": "開始一個會話後，訊息會顯示在這裡"
@@ -1222,6 +1229,38 @@
         "subjectLabel": "主題",
         "taskLabel": "任務",
         "nameLabel": "名稱：",
+        "field": {
+          "file": "檔案",
+          "notebook": "Notebook",
+          "command": "命令",
+          "old": "舊內容",
+          "new": "新內容",
+          "pattern": "模式",
+          "path": "路徑",
+          "query": "查詢",
+          "url": "URL",
+          "description": "描述",
+          "content": "內容",
+          "source": "來源內容",
+          "prompt": "提示詞",
+          "subject": "主題",
+          "taskId": "任務 ID",
+          "status": "狀態",
+          "skill": "Skill",
+          "args": "參數",
+          "offset": "位移",
+          "limit": "限制",
+          "glob": "Glob",
+          "type": "類型",
+          "output": "輸出",
+          "replaceAll": "全部替換",
+          "language": "語言",
+          "timeout": "逾時",
+          "background": "背景",
+          "agentType": "Agent 類型",
+          "library": "函式庫",
+          "libraryId": "函式庫 ID"
+        },
         "title": {
           "edit": "編輯",
           "command": "命令",
diff --git a/src/lib/adapters/ai-elements-adapter.ts b/src/lib/adapters/ai-elements-adapter.ts
index 664ea54..a41776f 100644
--- a/src/lib/adapters/ai-elements-adapter.ts
+++ b/src/lib/adapters/ai-elements-adapter.ts
@@ -60,6 +60,12 @@ export interface AdaptedMessage {
   model?: string | null
 }
 
+export interface AdapterMessageText {
+  attachedResources: string
+  toolCallFailed: string
+  planUpdated: string
+}
+
 type InlineToolSegment =
   | { kind: "text"; value: string }
   | { kind: "tool_call" | "tool_result"; value: string }
@@ -271,7 +277,8 @@ function parseInlineToolResultPayload(payload: string): {
 function expandInlineToolText(
   text: string,
   messageId: string,
-  blockIndex: number
+  blockIndex: number,
+  toolCallFailedText: string
 ): AdaptedContentPart[] | null {
   const segments = splitInlineToolSegments(text)
   if (!segments) return null
@@ -320,7 +327,7 @@ function expandInlineToolText(
         output = parsedResult.output
         if (parsedResult.isError) {
           state = "output-error"
-          errorText = output ?? "Tool call failed"
+          errorText = output ?? toolCallFailedText
         }
         index = lookahead
       }
@@ -345,7 +352,7 @@ function expandInlineToolText(
       toolCallId,
       output: parsedResult.output,
       errorText: parsedResult.isError
-        ? (parsedResult.output ?? "Tool call failed")
+        ? (parsedResult.output ?? toolCallFailedText)
         : undefined,
       state: parsedResult.isError ? "output-error" : "output-available",
     })
@@ -440,7 +447,10 @@ export function extractUserResourcesFromText(text: string): {
   }
 }
 
-function splitUserTextAndResources(parts: AdaptedContentPart[]): {
+function splitUserTextAndResources(
+  parts: AdaptedContentPart[],
+  attachedResourcesText: string
+): {
   parts: AdaptedContentPart[]
   resources: UserResourceDisplay[]
 } {
@@ -464,7 +474,7 @@ function splitUserTextAndResources(parts: AdaptedContentPart[]): {
   }
 
   if (nextParts.length === 0 && resources.length > 0) {
-    nextParts.push({ type: "text", text: "Attached resources" })
+    nextParts.push({ type: "text", text: attachedResourcesText })
   }
 
   return { parts: nextParts, resources }
@@ -545,7 +555,10 @@ function buildToolResultMap(
  * Transform a MessageTurn (from backend) to AdaptedMessage format.
  * Same correlation logic as adaptUnifiedMessage but operates on turn.blocks.
  */
-export function adaptMessageTurn(turn: MessageTurn): AdaptedMessage {
+export function adaptMessageTurn(
+  turn: MessageTurn,
+  text: Pick<AdapterMessageText, "attachedResources" | "toolCallFailed">
+): AdaptedMessage {
   const adaptedContent: AdaptedContentPart[] = []
   const resultMap = buildToolResultMap(turn.blocks)
   const matchedResultIds = new Set<string>()
@@ -557,7 +570,12 @@ export function adaptMessageTurn(turn: MessageTurn): AdaptedMessage {
     const block = turn.blocks[index]
 
     if (turn.role === "assistant" && block.type === "text") {
-      const expandedParts = expandInlineToolText(block.text, turn.id, index)
+      const expandedParts = expandInlineToolText(
+        block.text,
+        turn.id,
+        index,
+        text.toolCallFailed
+      )
       if (expandedParts) {
         adaptedContent.push(...expandedParts)
         continue
@@ -641,7 +659,7 @@ export function adaptMessageTurn(turn: MessageTurn): AdaptedMessage {
 
   const userSplit =
     turn.role === "user"
-      ? splitUserTextAndResources(adaptedContent)
+      ? splitUserTextAndResources(adaptedContent, text.attachedResources)
       : { parts: adaptedContent, resources: [] as UserResourceDisplay[] }
 
   return {
@@ -661,8 +679,11 @@ export function adaptMessageTurn(turn: MessageTurn): AdaptedMessage {
  * Transform all turns in a conversation to AdaptedMessage[].
  * Internally computes completedToolIds so callers don't need to.
  */
-export function adaptMessageTurns(turns: MessageTurn[]): AdaptedMessage[] {
-  return turns.map((turn) => adaptMessageTurn(turn))
+export function adaptMessageTurns(
+  turns: MessageTurn[],
+  text: Pick<AdapterMessageText, "attachedResources" | "toolCallFailed">
+): AdaptedMessage[] {
+  return turns.map((turn) => adaptMessageTurn(turn, text))
 }
 
 /**
@@ -942,19 +963,22 @@ function selectLiveToolOutput(params: {
 }
 
 function formatPlanEntries(
-  entries: Array<{ content: string; priority: string; status: string }>
+  entries: Array<{ content: string; priority: string; status: string }>,
+  planUpdatedText: string
 ): string {
   if (entries.length === 0) {
-    return "Plan updated"
+    return planUpdatedText
   }
   const lines = entries.map(
     (entry) => `- [${entry.status}] ${entry.content} (${entry.priority})`
   )
-  return `Plan updated:\n${lines.join("\n")}`
+  return `${planUpdatedText}:\n${lines.join("\n")}`
 }
 
 interface AdaptLiveMessageOptions {
   isLiveStreaming?: boolean
+  toolCallFailedText: string
+  planUpdatedText: string
 }
 
 function isReasoningBlock(block: LiveMessage["content"][number]): boolean {
@@ -976,7 +1000,7 @@ function findLastReasoningIndex(message: LiveMessage): number {
  */
 export function adaptLiveMessageFromAcp(
   message: LiveMessage,
-  options: AdaptLiveMessageOptions = {}
+  options: AdaptLiveMessageOptions
 ): AdaptedMessage {
   const isLiveStreaming = options.isLiveStreaming ?? true
   const adaptedContent: AdaptedContentPart[] = []
@@ -1034,7 +1058,7 @@ export function adaptLiveMessageFromAcp(
           output,
           errorText:
             state === "output-error"
-              ? selectedOutput || "Tool call failed"
+              ? selectedOutput || options.toolCallFailedText
               : undefined,
         })
         break
@@ -1043,7 +1067,7 @@ export function adaptLiveMessageFromAcp(
       case "plan":
         adaptedContent.push({
           type: "reasoning",
-          content: formatPlanEntries(block.entries),
+          content: formatPlanEntries(block.entries, options.planUpdatedText),
           isStreaming: index === lastStreamingReasoningIndex,
         })
         break
diff --git a/src/lib/prompt-draft.ts b/src/lib/prompt-draft.ts
index 04161b6..32cd61c 100644
--- a/src/lib/prompt-draft.ts
+++ b/src/lib/prompt-draft.ts
@@ -10,15 +10,24 @@ function isResourceLinkBlock(
   return block.type === "resource_link"
 }
 
-export function getPromptDraftDisplayText(draft: PromptDraft): string {
+export function getPromptDraftDisplayText(
+  draft: PromptDraft,
+  attachedResourcesFallback: string
+): string {
   const trimmed = draft.displayText.trim()
-  return trimmed || "Attached resources"
+  return trimmed || attachedResourcesFallback
 }
 
 export function buildUserMessageTextPartsFromDraft(
-  draft: PromptDraft
+  draft: PromptDraft,
+  attachedResourcesFallback: string
 ): AdaptedContentPart[] {
-  return [{ type: "text", text: getPromptDraftDisplayText(draft) }]
+  return [
+    {
+      type: "text",
+      text: getPromptDraftDisplayText(draft, attachedResourcesFallback),
+    },
+  ]
 }
 
 export function extractUserResourcesFromDraft(
diff --git a/src/lib/types.ts b/src/lib/types.ts
index d06617d..4e33000 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -23,6 +23,8 @@ export type AgentType =
 export type AppErrorCode =
   | "unknown"
   | "invalid_input"
+  | "configuration_missing"
+  | "configuration_invalid"
   | "not_found"
   | "already_exists"
   | "permission_denied"