iflytek/astron-agent · warning · ValueError

API requires Chinese (cn) as either source or target…

Error message

API requires Chinese (cn) as either source or target language. Current combination: {source_language} → {target_language} is not supported.

What it means

The `validate_language_combination` model_validator (mode="after") enforces that at least one of source_language/target_language is Chinese ("cn"), because the underlying iFlytek translation API only supports pairs involving Chinese. `is_valid_language_pair` returning False triggers this ValueError, wrapped by pydantic into a ValidationError. The message shows the exact offending pair.

Solutions

1. Route non-Chinese pairs to a different translation backend that supports them.
2. For a pair like en→ja, translate in two hops through Chinese (en→cn then cn→ja) if acceptable quality-wise.
3. Constrain the UI so target_language options depend on the chosen source (or vice versa) such that one side is always cn.
4. Check pair validity client-side with the same rule (source=='cn' || target=='cn') before calling.

Example fix

// before
await translate({ text, source_language: 'en', target_language: 'ja' }); // rejected
// after
if (source !== 'cn' && target !== 'cn') {
  const mid = await translate({ text, source_language: source, target_language: 'cn' });
  return translate({ text: mid, source_language: 'cn', target_language: target });
}
return translate({ text, source_language: source, target_language: target });

function isSupportedPair(source, target) {
  return source === 'cn' || target === 'cn';
}

try:
    inp = TranslationInput(**payload)
except ValidationError as e:
    if 'Chinese (cn)' in str(e):
        return error_response('该翻译接口要求源语言或目标语言为中文(cn)', 400)
    raise

When it happens

Trigger: Constructing TranslationInput with a pair like en→ja, fr→de, or any combination where neither side is "cn" — even when both codes are individually valid.

Common situations: Users pick two non-Chinese languages in the UI; generic translation clients reuse the endpoint for arbitrary pairs; routing all traffic to this API without checking pair support first.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Invalid source language
• Invalid target language
• Translation text cannot be empty
• Translation text cannot exceed 5000 characters
• 21600

AI-assisted analysis of iflytek/astron-agent@5e758547a8 (2026-09-12). Data as JSON: /api/errors/6a5bed05001dab60. Report an issue: GitHub.

Appendix: source

Thrown at core/plugin/aitools/service/translation/translation_service.py:79

            )
        return value

    @field_validator("source_language")
    @classmethod
    def validate_source_language(cls, value: str) -> str:
        """validate source language"""
        if value not in VALID_LANGUAGE_CODES:
            raise ValueError(
                f"Invalid source language: {value}.\n"
                f"Valid options: {list(VALID_LANGUAGE_CODES)}"
            )
        return value

    @model_validator(mode="after")
    def validate_language_combination(self) -> "TranslationInput":
        """Validate that at least one language is Chinese (cn)"""
        if not is_valid_language_pair(self.source_language, self.target_language):
            raise ValueError(
                "API requires Chinese (cn) as either source or target language. "
                f"Current combination: {self.source_language} → {self.target_language} "
                "is not supported."
            )
        return self


@api_service(
    method="POST",
    path="/aitools/v1/translation",
    query=None,
    body=TranslationInput,
    response=BaseResponse,
    summary="Translate text from Chinese (cn) to other languages",
    description="Translate text from Chinese (cn) to other languages",
    tags=["public_cn"],
    deprecated=True,
)

View on GitHub (pinned to 5e758547a8)