HKUDS/Vibe-Trading · error · ValueError

{field_name}={value!r} is not ISO-8601 (YYYY-MM-DD); pass an

Error message

{field_name}={value!r} is not ISO-8601 (YYYY-MM-DD); pass an explicit date_format instead of relying on inference

What it means

normalize_date tries ISO-8601 (date and datetime) parsing on strings and, when both fail, raises with the offending value and a hint to pass an explicit date_format instead of relying on inference.

Source

Thrown at agent/src/entities/models.py:131

    Raises:
        ValueError: If the value is not a supported type or not ISO-8601.
    """
    if isinstance(value, datetime):
        return value.date()
    if isinstance(value, date):
        return value
    if isinstance(value, str):
        text = value.strip()
        if not text:
            raise ValueError(f"{field_name} is required and cannot be empty")
        try:
            return date.fromisoformat(text)
        except ValueError:
            pass
        try:
            return datetime.fromisoformat(text).date()
        except ValueError as exc:
            raise ValueError(
                f"{field_name}={value!r} is not ISO-8601 (YYYY-MM-DD); pass an "
                "explicit date_format instead of relying on inference"
            ) from exc
    raise ValueError(
        f"{field_name} must be a date, datetime, or ISO-8601 string, "
        f"got {type(value).__name__}"
    )


@dataclass(frozen=True)
class Entity:
    """A legal entity that issues, manages, or faces an instrument.

    Attributes:
        entity_id: Stable identifier, e.g. an LEI, a CIK, or a local key.
        name: Human-readable legal name.
        entity_type: Role the entity plays; see ``EntityType``.
        domicile: Country or jurisdiction code, free-form and optional.

View on GitHub (pinned to 80ffdda44c)

Solutions

1. Normalize to ISO: pd.to_datetime(v).date() or datetime.strptime upstream
2. Pass an explicit date_format where the API supports it (e.g. load_panel(date_format='%d/%m/%Y'))
3. Convert strings to datetime.date objects before passing

Example fix

# before
panel = load_panel('p.csv')  # dates like 31/03/2024
# after
panel = load_panel('p.csv', date_format='%d/%m/%Y')

from datetime import datetime
try: datetime.fromisoformat(d.strip())
except ValueError: d = datetime.strptime(d.strip(), '%d/%m/%Y').date().isoformat()

except ValueError as e:
    if 'not ISO-8601' in str(e): parse with strptime/date_format and retry

When it happens

Trigger: Passing date strings like '2024/03/31', '31-03-2024', or 'Mar 2024' anywhere a date is expected without a date_format.

Common situations: Locale-formatted exports (DD/MM/YYYY), slash-separated dates, or month-name formats from spreadsheets.

Related errors

• {field_name} must be a date, datetime, or ISO-8601 string, g
• {field_name} must be a string, got {type(value).__name__}
• {field_name} is required and cannot be empty
• {field_name} cannot contain whitespace, got {value!r}
• entity_id is required and cannot be empty

AI-assisted analysis of HKUDS/Vibe-Trading@80ffdda44c (2026-08-28). Data as JSON: /api/errors/a31c484aa3036a8b. Report an issue: GitHub.