can1357/oh-my-pi · error · NameError

UsageError: Cell magic function '%%{name}' not found.

Error message

UsageError: Cell magic function '%%{name}' not found.

What it means

Cell magics (%%name) are dispatched by __omp_magic_cell against the registered cell-magic table. Unknown names raise NameError formatted like IPython's UsageError: "Cell magic function '%%name' not found.". Note that a magic implemented as a line magic is still unknown here — the tables are separate.

Source

Thrown at packages/coding-agent/src/eval/py/runner.py:838

        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
    )
    _stream_process_output(proc)
    proc.wait()
    return proc.returncode


def __omp_magic(name: str, args: str) -> Any:
    fn = _LINE_MAGICS.get(name)
    if fn is None:
        raise NameError(f"UsageError: Line magic function '%{name}' not found.")
    return fn(args)


def __omp_magic_cell(name: str, args: str, body: str) -> Any:
    fn = _CELL_MAGICS.get(name)
    if fn is None:
        raise NameError(f"UsageError: Cell magic function '%%{name}' not found.")
    return fn(args, body)


class _ShellResult(list):
    """Result of ``!cmd`` — list of stripped output lines."""

    def __init__(self, lines: list[str], returncode: int) -> None:
        super().__init__(lines)
        self.returncode = returncode

    @property
    def n(self) -> str:  # IPython compat
        return "\n".join(self)

    @property
    def s(self) -> str:  # IPython compat
        return " ".join(self)

View on GitHub (pinned to 9690622007)

Solutions

1. Verify the magic exists as a cell magic (line and cell tables are separate)
2. Remove or rewrite the cell using plain Python if the magic is unsupported
3. Check the header line for typos — %%name must be on its own first line
4. Register the cell magic with @cell_magic if extending the runner

Example fix

// before
%%capture out
print('hi')
// after
captured = io.StringIO()
with contextlib.redirect_stdout(captured):
    print('hi')

# confirm the cell magic exists before using %%name
KNOWN_CELL_MAGICS = {"bash"}  # from runner docs
if name not in KNOWN_CELL_MAGICS:
    ...

try:
    __omp_magic_cell(name, args, body)
except NameError as e:
    if "Cell magic function" in str(e):
        print(f"%%{name} not available; rewrite the cell in Python")

When it happens

Trigger: Using %%bash, %%time, etc. when that cell magic is not registered; or using a name that exists only as a line magic; or typos in the cell-magic header line.

Common situations: Porting IPython notebooks that rely on cell magics this runner does not implement, writing %% instead of % (or vice versa) for an existing magic.

Related errors

• UsageError: Line magic function '%{name}' not found.
• Usage: %set_env KEY VALUE
• Usage: %run <path>
• Command aborted
• Command timed out

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/028905530638a792. Report an issue: GitHub.