FoundationAgents/MetaGPT · error · FileExistsError

File '{filename}' already exists.

Error message

File '{filename}' already exists.

What it means

Raised by Editor.create_file when the target path already exists (any filesystem entry: file, directory, or symlink). create_file is write-once by design; it will not truncate or overwrite existing content, so it refuses rather than destroying data.

Source

Thrown at metagpt/tools/libs/editor.py:366

        self._check_current_file()

        with self.current_file.open() as file:
            total_lines = max(1, sum(1 for _ in file))
        self.current_line = self._clamp(self.current_line - self.window, 1, total_lines)
        output = self._cur_file_header(self.current_file, total_lines)
        output += self._print_window(self.current_file, self.current_line, self.window)
        return output

    async def create_file(self, filename: str) -> str:
        """Creates and opens a new file with the given name.

        Args:
            filename: str: The name of the file to create. If the parent directory does not exist, it will be created.
        """
        filename = self._try_fix_path(filename)

        if filename.exists():
            raise FileExistsError(f"File '{filename}' already exists.")
        await awrite(filename, "\n")

        self.open_file(filename)
        return f"[File {filename} created.]"

    @staticmethod
    def _append_impl(lines, content):
        """Internal method to handle appending to a file.

        Args:
            lines: list[str]: The lines in the original file.
            content: str: The content to append to the file.

        Returns:
            content: str: The new content of the file.
            n_added_lines: int: The number of lines added to the file.
        """
        content_lines = content.splitlines(keepends=True)

View on GitHub (pinned to 11cdf466d0)

Solutions

1. Check filename.exists() first and open_file instead when the file already exists
2. If regeneration is intended, delete or move the old file before create_file
3. Guard retries: only call create_file when the file is absent

Example fix

// before
editor.create_file('src/new_module.py')  # FileExistsError

// after
if filename.exists():
    editor.open_file(str(filename))
else:
    editor.create_file(str(filename))

from pathlib import Path
if Path(filename).exists():
    editor.open_file(filename)
else:
    editor.create_file(filename)

def should_create(p: str) -> bool:
    return not Path(p).exists()

try:
    editor.create_file(filename)
except FileExistsError:
    editor.open_file(filename)

When it happens

Trigger: editor.create_file('a.py') when a.py already exists on disk; re-running a generation step that already created the file; passing a path that collides with an existing directory.

Common situations: Retry loops in agent workflows re-invoking create_file after a partial failure; scaffolding scripts run twice; idempotency expectations where the tool is deliberately non-idempotent.

Related errors

• File {path} not found
• Could not access or create directories.
• File {file_name} not found.
• Directory {dir_path} not found
• No file open. Use the open_file function first.

AI-assisted analysis of FoundationAgents/MetaGPT@11cdf466d0 (2026-08-14). Data as JSON: /api/errors/4f0848272949a105. Report an issue: GitHub.