Moatless MCP Server

Instructions

Implementation Reference

• src/moatless_mcp/tools/advanced_tools.py:189-227 (handler)

  Main handler for the view_code MCP tool. Processes input arguments, calls the core view_code implementation from AdvancedSearchTools, formats the response with code sections.
  async def execute(self, arguments: Dict[str, Any]) -> ToolResult: """Execute the view_code tool.""" try: file_path = arguments.get("file_path") start_line = arguments.get("start_line") end_line = arguments.get("end_line") span_ids = arguments.get("span_ids") if not file_path: return self.format_error("file_path is required") search_tools = AdvancedSearchTools(self.workspace.config, self.workspace.workspace_path) result = await search_tools.view_code(file_path, start_line, end_line, span_ids) if "error" in result: return self.format_error(result["error"]) # Format the response message = f"Code view for {result['file_path']} (Total lines: {result['total_lines']}):\n\n" for section in result['content_sections']: if 'span_id' in section: message += f"=== {section['span_type'].title()}: {section['span_id']} ===\n" message += f"Lines {section['start_line']}-{section['end_line']}:\n" else: message += f"=== Lines {section['start_line']}-{section['end_line']} ===\n" message += section['content'] message += "\n\n" return ToolResult( success=True, message=message, properties=result ) except Exception as e: logger.error(f"Error in view_code: {e}") return self.format_error(str(e))
• src/moatless_mcp/tools/advanced_tools.py:164-187 (schema)

  Input schema defining parameters for the view_code tool: file_path (required), start_line, end_line, span_ids.
  def input_schema(self) -> Dict[str, Any]: return { "type": "object", "properties": { "file_path": { "type": "string", "description": "Path to the file to view" }, "start_line": { "type": "integer", "description": "Starting line number (1-indexed)" }, "end_line": { "type": "integer", "description": "Ending line number (1-indexed)" }, "span_ids": { "type": "array", "items": {"type": "string"}, "description": "List of span IDs to view (class names, function names, etc.)" } }, "required": ["file_path"] }
• src/moatless_mcp/tools/registry.py:64-69 (registration)

  Registration of ViewCodeTool instance in the ToolRegistry's default tools list.
  FindClassTool(self.workspace), FindFunctionTool(self.workspace), ViewCodeTool(self.workspace), SemanticSearchTool(self.workspace), RunTestsTool(self.workspace),
• src/moatless_mcp/tools/advanced_search.py:285-407 (helper)

  Core helper function implementing the view_code logic: reads file, handles line ranges or span_ids (classes/functions), uses tree-sitter or regex to find code blocks, extracts and sections content.
  async def view_code(self, file_path: str, start_line: Optional[int] = None, end_line: Optional[int] = None, span_ids: Optional[List[str]] = None) -> Dict[str, Any]: """View specific code sections with intelligent context. Args: file_path: Path to the file to view start_line: Starting line number (1-indexed) end_line: Ending line number (1-indexed) span_ids: List of span IDs to view (class names, function names, etc.) Returns: Dictionary with code content and metadata """ try: # Validate and normalize file path full_path = self.workspace_root / file_path if not self.config.is_file_allowed(full_path): return {"error": "File access not allowed"} if not full_path.exists(): return {"error": f"File not found: {file_path}"} if not full_path.is_file(): return {"error": f"Path is not a file: {file_path}"} # Read file content try: with open(full_path, 'r', encoding='utf-8', errors='ignore') as f: content = f.read() except Exception as e: return {"error": f"Cannot read file: {str(e)}"} lines = content.split('\n') total_lines = len(lines) result = { "file_path": file_path, "total_lines": total_lines, "content_sections": [] } # Handle span_ids (enhanced implementation) if span_ids: for span_id in span_ids: found_matches = [] # Handle different span_id formats if '.' in span_id: # Handle ClassName.method_name format parts = span_id.split('.') if len(parts) == 2: class_name, method_name = parts found_matches.extend(self._find_class_method(content, lines, class_name, method_name)) else: # Handle simple class or function names found_matches.extend(self._find_simple_span(content, lines, span_id)) # Process matches for match_line, span_type, end_line in found_matches: try: # Validate line numbers if match_line > len(lines) or match_line < 1: continue # Extract the content start_idx = match_line - 1 # Convert to 0-based index end_idx = min(end_line, total_lines) section_content = '\n'.join(lines[start_idx:end_idx]) result["content_sections"].append({ "span_id": span_id, "span_type": span_type, "start_line": match_line, "end_line": end_idx, "content": section_content }) except Exception as e: logger.warning(f"Error processing span_id {span_id}: {e}") continue # If no matches found for span_ids, add error info if not result["content_sections"]: result["content_sections"].append({ "error": f"No matches found for span_ids: {', '.join(span_ids)}", "start_line": 1, "end_line": 1, "content": f"# No code blocks found matching: {', '.join(span_ids)}\n# Available in this file, please use line numbers or search for specific patterns." }) # Handle line range elif start_line is not None: start_idx = max(1, start_line) - 1 end_idx = min(total_lines, end_line or start_line) if end_line else start_idx + 1 if start_idx >= total_lines: return {"error": f"Start line {start_line} exceeds file length {total_lines}"} section_content = '\n'.join(lines[start_idx:end_idx]) result["content_sections"].append({ "start_line": start_idx + 1, "end_line": end_idx, "content": section_content }) # Return entire file if no specific range requested else: if total_lines > 1000: # Limit large files result["content_sections"].append({ "start_line": 1, "end_line": 100, "content": '\n'.join(lines[:100]) + f"\n... (file has {total_lines} total lines, showing first 100)" }) else: result["content_sections"].append({ "start_line": 1, "end_line": total_lines, "content": content }) return result except Exception as e: logger.error(f"Error in view_code: {e}") return {"error": f"Failed to view code: {str(e)}"}