huggingface/smolagents · error · AssertionError

{msg}

Error message

{msg}

What it means

An assert statement failed and included a custom message (assert cond, msg); the interpreter evaluates msg and raises AssertionError with it. This is the agent-code's own assertion failing, not an interpreter bug.

Source

Thrown at src/smolagents/local_python_executor.py:1229

            raise exc from cause
        else:
            raise exc
    else:
        raise InterpreterError("Re-raise is not supported without an active exception")


def evaluate_assert(
    assert_node: ast.Assert,
    state: dict[str, Any],
    static_tools: dict[str, Callable],
    custom_tools: dict[str, Callable],
    authorized_imports: list[str],
) -> None:
    test_result = evaluate_ast(assert_node.test, state, static_tools, custom_tools, authorized_imports)
    if not test_result:
        if assert_node.msg:
            msg = evaluate_ast(assert_node.msg, state, static_tools, custom_tools, authorized_imports)
            raise AssertionError(msg)
        else:
            # Include the failing condition in the assertion message
            test_code = ast.unparse(assert_node.test)
            raise AssertionError(f"Assertion failed: {test_code}")


def evaluate_with(
    with_node: ast.With,
    state: dict[str, Any],
    static_tools: dict[str, Callable],
    custom_tools: dict[str, Callable],
    authorized_imports: list[str],
) -> None:
    contexts = []
    for item in with_node.items:
        context_expr = evaluate_ast(item.context_expr, state, static_tools, custom_tools, authorized_imports)
        enter_result = context_expr.__enter__()
        contexts.append(context_expr)

View on GitHub (pinned to 30bb116109)

Solutions

1. Read the custom message to identify which check failed and fix the upstream data/logic
2. Replace assert with explicit if not cond: raise ValueError(...) for better control
3. Make assertions robust to legitimate edge cases (e.g. allow empty results if valid)

Example fix

# before
assert resp['status'] == 'ok', 'bad status'
# after
if resp.get('status') != 'ok':
    raise ValueError(f"unexpected status: {resp.get('status')}")

if not (resp and resp.get('status') == 'ok'):
    raise ValueError(f"bad response: {resp!r}")

try:
    evaluate_python(code, ...)
except AssertionError as e:
    # read the custom msg, fix upstream data/logic, retry
    ...

When it happens

Trigger: assert 1 == 2, 'sanity check failed' or assert result is not None, 'API returned nothing' where the condition evaluates falsy.

Common situations: Agent code self-checks LLM/tool outputs and asserts non-None, correct type, or expected value; validation assertions on parsed JSON; asserting a file exists after a download step.

Related errors

• Assertion failed: {test_code}
• Check {check_function.__name__} failed with error: {e}
• {e}
• Cannot unpack non-dict value in **kwargs: {type(starred_dict
• super() needs at least one argument

AI-assisted analysis of huggingface/smolagents@30bb116109 (2026-08-28). Data as JSON: /api/errors/802b521835ea2946. Report an issue: GitHub.