agentscope-ai/agentscope · error · FileNotFoundError

not found in container

Error message

not found in container: {path}\nstderr: {result.stderr.decode(errors='replace')}

What it means

AppleContainerWorkspace's read_file runs `cat <path>` inside the container via exec_shell; a non-zero exit code (usually 'No such file or directory') is surfaced as FileNotFoundError with the path and container stderr.

Solutions

Use the path relative to the container workspace root, not a host path.
Verify the file exists first: await workspace.list_dir(...) or exec `test -f <path>`.
Create/write the file before reading it.
Handle FileNotFoundError and fall back to a default.

Example fix

# before
data = await ws.read_file("/Users/me/project/main.py")

# after
data = await ws.read_file("main.py")  # path inside the container

Defensive patterns

Strategy: try-catch

Validate before calling

entries = await ws.list_dir(dirname(path))
assert any(e.name == basename(path) for e in entries), "file missing"

Try / catch

try:
    data = await ws.read_file(path)
except FileNotFoundError:
    data = default_bytes  # or create the file first

Prevention

Always use container-relative paths, never host paths.
Write files before reading them; check with list_dir/exec test -f.

When it happens

Trigger: Calling await workspace.read_file(path) where path does not exist inside the container filesystem, or is a directory/unreadable (cat fails). Paths are container-relative, not host-relative.

Common situations: Using host absolute paths like /Users/me/file.txt that don't exist in the container, reading a file before it was written into the workspace, typos in relative paths, or wrong working directory assumption inside the container.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

AI-assisted analysis of agentscope-ai/agentscope@e90f1c7592 (2026-08-28). Data as JSON: /api/errors/7ee2edea6d141fda. Report an issue: GitHub.

Appendix: source

Thrown at src/agentscope/workspace/_applecontainer/_applecontainer_backend.py:159

    async def read_file(self, path: str) -> bytes:
        """Read a file from the container via ``container exec cat``.

        Args:
            path (`str`):
                Path to the file inside the container.

        Returns:
            `bytes`:
                The raw file contents.

        Raises:
            `FileNotFoundError`:
                If the path does not exist inside the container.
        """
        result = await self.exec_shell(["cat", path])
        if result.exit_code != 0:
            raise FileNotFoundError(
                f"not found in container: {path}\n"
                f"stderr: {result.stderr.decode(errors='replace')}",
            )
        return result.stdout

    async def write_file(self, path: str, data: bytes) -> None:
        """Write *data* to a file inside the container via
        ``container cp``.

        Writes *data* to a host-side temp file, then copies it into the
        container.

        Args:
            path (`str`):
                Destination path inside the container.
            data (`bytes`):
                The raw bytes to write.
        """

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