fix: restore AppError::Internal for AST parser error, keeping BadRequest for JSON schema validation

server/src/handlers/git.rs

@@ -28,7 +28,7 @@ impl McpTool for GetActiveWorktreeContextHandler {
     ) -> crate::error::Result<String> {
         let result =
             tokio::task::spawn_blocking(move || -> crate::error::Result<serde_json::Value> {
-                let cwd = env::current_dir().map_err(|e| e.to_string())?;
+                let cwd = env::current_dir().map_err(|e| crate::error::AppError::Internal(format!("Failed to get current directory: {}", e)))?;
                 let repo = git2::Repository::discover(&cwd).map_err(|e| {
                     crate::error::AppError::Internal(format!("Not in a git repository: {}", e))
                 })?;
@@ -108,7 +108,7 @@ impl McpTool for QueryGitDiffsHandler {
 
     async fn execute(&self, args: Value, state: Arc<MemoryState>) -> crate::error::Result<String> {
         let req: crate::tools::QueryGitDiffsTool =
-            serde_json::from_value(args).map_err(|e| e.to_string())?;
+            serde_json::from_value(args).map_err(|e| crate::error::AppError::BadRequest(format!("Schema validation failed. Your JSON arguments do not match the expected tool schema: {}", e)))?;
         let limit = req.limit.unwrap_or(5);
         let q = req.query.to_lowercase();