can1357/oh-my-pi · warning · ValueError

Usage: %set_env KEY VALUE

Error message

Usage: %set_env KEY VALUE

What it means

The %set_env line magic sets an OS environment variable for the eval session. It requires exactly KEY VALUE arguments; otherwise it raises ValueError with a usage string. It performs no other validation of key or value.

Source

Thrown at packages/coding-agent/src/eval/py/runner.py:655

@line_magic("env")
def _magic_env(args: str) -> Any:
    args = args.strip()
    if not args:
        return dict(sorted(os.environ.items()))
    if "=" in args:
        key, value = args.split("=", 1)
        os.environ[key.strip()] = value.strip()
        return value.strip()
    return os.environ.get(args)


@line_magic("set_env")
def _magic_set_env(args: str) -> str:
    parts = args.split(None, 1)
    if len(parts) != 2:
        raise ValueError("Usage: %set_env KEY VALUE")
    key, value = parts
    os.environ[key] = value
    return value


@line_magic("time")
def _magic_time(args: str) -> Any:
    start = time.perf_counter()
    result = eval(args, _STATE.user_ns)
    elapsed = time.perf_counter() - start
    sys.stdout.write(f"Wall time: {elapsed * 1000:.2f} ms\n")
    _emit_status("time", elapsed_ms=round(elapsed * 1000, 3))
    return result


@line_magic("timeit")
def _magic_timeit(args: str) -> None:
    import timeit as _timeit

View on GitHub (pinned to 9690622007)

Solutions

1. Use space-separated form: %set_env KEY VALUE
2. Do not use KEY=VALUE syntax — split(None,1) will not parse it into two parts
3. Quote the value if it contains spaces: %set_env KEY "some value"

Example fix

// before
%set_env API_KEY=abc123
// after
%set_env API_KEY abc123

parts = args.split(None, 1)
if len(parts) != 2:
    raise ValueError("Usage: %set_env KEY VALUE")  # pre-check mirrors the magic

try:
    %set_env KEY VALUE
except ValueError as e:
    if "Usage: %set_env" in str(e):
        # rewrite KEY=VALUE form
        key, _, value = args.partition('=')
        %set_env KEY VALUE

When it happens

Trigger: Running %set_env with zero or one argument — e.g. '%set_env' alone, '%set_env KEY' without a value, or '%set_env KEY=VALUE' (the = form is not split; it becomes one part).

Common situations: Copy-pasting IPython's %set_env KEY=value syntax, forgetting the value, or quoting issues causing shlex-less split() to merge tokens.

Related errors

• Usage: %run <path>
• UsageError: Line magic function '%{name}' not found.
• UsageError: Cell magic function '%%{name}' not found.
• using '-' to denote standard input does not work in file sys
• Anthropic cache refresh response omitted usage

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/7a077f9ccfc2b932. Report an issue: GitHub.