_FilesystemClaudeFileToolMiddleware Class — langchain Architecture

Source Code

libs/partners/anthropic/langchain_anthropic/middleware/anthropic_tools.py lines 657–1061

class _FilesystemClaudeFileToolMiddleware(AgentMiddleware):
    """Base class for filesystem-based file tool middleware (internal)."""

    def __init__(
        self,
        *,
        tool_type: str,
        tool_name: str,
        root_path: str,
        allowed_prefixes: list[str] | None = None,
        max_file_size_mb: int = 10,
        system_prompt: str | None = None,
    ) -> None:
        """Initialize.

        Args:
            tool_type: Tool type identifier.
            tool_name: Tool name.
            root_path: Root directory for file operations.
            allowed_prefixes: Optional list of allowed virtual path prefixes.
            max_file_size_mb: Maximum file size in MB.
            system_prompt: Optional system prompt to inject.
        """
        self.tool_type = tool_type
        self.tool_name = tool_name
        self.root_path = Path(root_path).resolve()
        self.allowed_prefixes = allowed_prefixes or ["/"]
        self.max_file_size_bytes = max_file_size_mb * 1024 * 1024
        self.system_prompt = system_prompt

        # Create root directory if it doesn't exist
        self.root_path.mkdir(parents=True, exist_ok=True)

        # Create tool that will be executed by the tool node
        @tool(tool_name)
        def file_tool(
            runtime: ToolRuntime,
            command: str,
            path: str,
            file_text: str | None = None,
            old_str: str | None = None,
            new_str: str | None = None,
            insert_line: int | None = None,
            new_path: str | None = None,
            view_range: list[int] | None = None,
        ) -> Command | str:
            """Execute file operations on filesystem.

            Args:
                runtime: Tool runtime providing `tool_call_id`.
                command: Operation to perform.
                path: File path to operate on.
                file_text: Full file content for create command.
                old_str: String to replace for `str_replace` command.
                new_str: Replacement string for `str_replace` command.
                insert_line: Line number for insert command.
                new_path: New path for rename command.
                view_range: Line range `[start, end]` for view command.

            Returns:
                Command for message update or string result.
            """
            # Build args dict for handler methods
            args: dict[str, Any] = {"path": path}
            if file_text is not None:
                args["file_text"] = file_text
            if old_str is not None:
                args["old_str"] = old_str
            if new_str is not None:
                args["new_str"] = new_str
            if insert_line is not None:
                args["insert_line"] = insert_line
            if new_path is not None:
                args["new_path"] = new_path
            if view_range is not None:
                args["view_range"] = view_range

            # Route to appropriate handler based on command
            try:
                if command == "view":
                    return self._handle_view(args, runtime.tool_call_id)