rohitg00/ai-engineering-from-scratch · error · ValueError

enum must be a list

Error message

enum must be a list

What it means

Error "enum must be a list" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/21-tool-registry-schema-validation/code/main.py:123

        _walk(rec.schema, args, "", errors)
        if errors:
            return errors
        return Ok()


def validate_schema_shape(schema: dict) -> None:
    """Reject schemas using keywords outside the supported subset."""
    if not isinstance(schema, dict):
        raise ValueError("schema must be a dict")
    unknown = set(schema.keys()) - ALLOWED_KEYWORDS
    if unknown:
        raise ValueError(f"unsupported schema keywords: {sorted(unknown)}")
    t = schema.get("type")
    if t is not None and t not in PRIMITIVE_TYPE_MAP:
        raise ValueError(f"unsupported type: {t!r}")
    enum_vals = schema.get("enum")
    if enum_vals is not None and not isinstance(enum_vals, list):
        raise ValueError("enum must be a list")
    min_len = schema.get("minLength")
    if min_len is not None:
        if isinstance(min_len, bool) or not isinstance(min_len, int) or min_len < 0:
            raise ValueError("minLength must be a non-negative integer")
    max_len = schema.get("maxLength")
    if max_len is not None:
        if isinstance(max_len, bool) or not isinstance(max_len, int) or max_len < 0:
            raise ValueError("maxLength must be a non-negative integer")
    if min_len is not None and max_len is not None and min_len > max_len:
        raise ValueError("minLength cannot be greater than maxLength")
    pattern = schema.get("pattern")
    if pattern is not None and not isinstance(pattern, str):
        raise ValueError("pattern must be a string")
    props = schema.get("properties")
    if props is not None:
        if not isinstance(props, dict):
            raise ValueError("properties must be a dict")
        for pname, psub in props.items():

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/21-tool-registry-schema-validation/code/main.py:123 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/15650058867b60bd. Report an issue: GitHub.