bytedance/deer-flow · error · HTTPException

Path is not a file: {path}

Error message

Path is not a file: {path}

What it means

HTTP 400 from _load_editable_artifact: lstat succeeded but the mode is not S_ISREG (and not a symlink, which 415 catches first). The path exists but is a directory, FIFO, device, or socket — the text editor only operates on regular files.

Source

Thrown at backend/app/gateway/routers/artifacts.py:85

def _normalize_editable_artifact_path(path: str) -> str:
    stripped = path.lstrip("/")
    if not stripped.startswith(_EDITABLE_OUTPUTS_PREFIX):
        raise HTTPException(status_code=400, detail="Only files in /mnt/user-data/outputs can be edited")
    if ".skill/" in stripped or stripped.endswith(".skill"):
        raise HTTPException(status_code=415, detail="Skill archives cannot be edited in the artifacts panel")
    return f"/{stripped}"


def _load_editable_artifact(actual_path: Path, path: str, expected_sha256: str) -> tuple[bytes, os.stat_result]:
    try:
        file_stat = os.lstat(actual_path)
    except FileNotFoundError:
        raise HTTPException(status_code=404, detail=f"Artifact not found: {path}") from None
    if stat.S_ISLNK(file_stat.st_mode):
        raise HTTPException(status_code=415, detail="Symlinked artifacts cannot be edited")
    if not stat.S_ISREG(file_stat.st_mode):
        raise HTTPException(status_code=400, detail=f"Path is not a file: {path}")
    if file_stat.st_size > MAX_EDITABLE_ARTIFACT_BYTES:
        raise HTTPException(status_code=413, detail="Artifact is too large to edit")

    current = actual_path.read_bytes()
    if len(current) > MAX_EDITABLE_ARTIFACT_BYTES:
        raise HTTPException(status_code=413, detail="Artifact is too large to edit")
    if b"\x00" in current:
        raise HTTPException(status_code=415, detail="Binary artifacts cannot be edited")
    try:
        current.decode("utf-8")
    except UnicodeDecodeError:
        raise HTTPException(status_code=415, detail="Only UTF-8 text artifacts can be edited") from None

    current_sha256 = hashlib.sha256(current).hexdigest()
    if current_sha256 != expected_sha256:
        raise HTTPException(status_code=412, detail="Artifact changed since it was opened")
    return current, file_stat

View on GitHub (pinned to 1dd6ba1acb)

Solutions

1. Fix the client path to point at a concrete file inside the directory
2. Filter directories out of anything the user can click Edit on
3. If a special file is intentional, it is not editable — remove it from the editor surface

Example fix

// before
await client.put(EDIT_URL, json={"path": "mnt/user-data/outputs/report", ...})

// after
await client.put(EDIT_URL, json={"path": "mnt/user-data/outputs/report/summary.md", ...})

import os, stat

def is_regular_file(path: str) -> bool:
    try:
        return stat.S_ISREG(os.lstat(path).st_mode)
    except OSError:
        return False

import os, stat

def is_editable_target(path: str) -> bool:
    """Regular non-symlink file under outputs."""
    try:
        st = os.lstat(path)
    except OSError:
        return False
    return stat.S_ISREG(st.st_mode) and path.lstrip("/").startswith("mnt/user-data/outputs/")

When it happens

Trigger: PUT edit-artifact with a path that resolves to a directory (e.g. 'mnt/user-data/outputs/report/' with trailing content being a dir) or a special file created by sandbox tooling.

Common situations: Path-building bugs appending a filename to a directory path that already ends at the directory, artifacts listings surfacing directories as entries, or agent-created FIFOs/device nodes in outputs.

Related errors

• Only files in /mnt/user-data/outputs can be edited
• Path is not a file: {skill_file_path}
• Symlinked artifacts cannot be edited
• {e}
• Skill archives cannot be edited in the artifacts panel

AI-assisted analysis of bytedance/deer-flow@1dd6ba1acb (2026-08-14). Data as JSON: /api/errors/b266ae0c898a405c. Report an issue: GitHub.