alibaba/nacos · error · NacosApiException

PARAMETER_MISSING

PARAMETER_MISSING

Error message

Required parameter 'label' type String is not present

What it means

Thrown by PromptLabelForm.validate() when label is blank. This form extends PromptForm and backs the label-unbind endpoint (PromptAdminController.unbindLabel). super.validate() checks promptKey first. Maps to ErrorCode.PARAMETER_MISSING (code 10000), HTTP 400.

Source

Thrown at ai/src/main/java/com/alibaba/nacos/ai/form/prompt/PromptLabelForm.java:37

import com.alibaba.nacos.api.exception.NacosException;
import com.alibaba.nacos.api.exception.api.NacosApiException;
import com.alibaba.nacos.api.model.v2.ErrorCode;
import com.alibaba.nacos.common.utils.StringUtils;

/**
 * Prompt label form.
 *
 * @author nacos
 */
public class PromptLabelForm extends PromptForm {
    
    private String label;
    
    @Override
    public void validate() throws NacosApiException {
        super.validate();
        if (StringUtils.isBlank(label)) {
            throw new NacosApiException(NacosException.INVALID_PARAM, ErrorCode.PARAMETER_MISSING,
                "Required parameter 'label' type String is not present");
        }
    }
    
    public String getLabel() {
        return label;
    }
    
    public void setLabel(String label) {
        this.label = label;
    }
}

View on GitHub (pinned to 9b989acdf1)

Solutions

  1. Provide the specific non-blank label to unbind.
  2. To remove multiple labels, call once per label.
  3. Ensure promptKey is also present.

Example fix

// before
promptKey=myPrompt
// after
promptKey=myPrompt&label=stable
Defensive patterns

Strategy: validation

Validate before calling

if (label == null || label.trim().isEmpty()) {
    throw new IllegalArgumentException("label required to unbind");
}

Type guard

static boolean hasLabel(String l) {
    return l != null && !l.trim().isEmpty();
}

Try / catch

catch (NacosApiException e) {
    if (e.getErrCode() == 10000 && e.getMessage().contains("'label'")) { /* supply label */ }
}

Prevention

When it happens

Trigger: Calling DELETE/unbind label (PromptAdminController.unbindLabel) with promptKey set but label omitted.

Common situations: Client sends only promptKey to unbind all labels (not supported — one label at a time); UI submits before selecting which label to remove; field named differently on caller side.

Related errors

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/befef27f939e7995. Report an issue: GitHub.