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

unsupported type

Error message

unsupported type: {t!r}

What it means

Type-vocabulary check in validate_schema_shape: the schema's "type" value is not in PRIMITIVE_TYPE_MAP, i.e. not one of the supported JSON primitive types (object, array, string, integer, number, boolean, null). The mini validator has no checker for the requested type, so it refuses the schema.

Solutions

1. Use one of the supported type strings from PRIMITIVE_TYPE_MAP
2. Check for typos like "int" instead of "integer" or "str" instead of "string"
3. Split union types into the documented list form if supported, or drop the constraint
4. Add genuinely new types to PRIMITIVE_TYPE_MAP together with their checker

When it happens

Trigger: Thrown at phases/19-capstone-projects/21-tool-registry-schema-validation/code/main.py:120 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/b62477d2c26d99b7. Report an issue: GitHub.

Appendix: source

Thrown at phases/19-capstone-projects/21-tool-registry-schema-validation/code/main.py:120

    def validate(self, name: str, args: Any) -> Ok | list[ValidationError]:
        rec = self.get(name)
        errors: list[ValidationError] = []
        _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:

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