linshenkx/prompt-optimizer · error · EvaluationValidationError

${label} must not be empty.

Error message

${label} must not be empty.

What it means

validateContentBlock requires every evaluation content block (e.g. a test case input) to be present. This variant fires when the block itself is undefined/null — not just empty text — so the evaluation payload is structurally incomplete.

Source

Thrown at packages/core/src/services/evaluation/service.ts:1697

        throw new EvaluationValidationError(
          `${label} #${index + 1} must provide either assetId or b64.`
        );
      }

      if (assetId && b64) {
        throw new EvaluationValidationError(
          `${label} #${index + 1} must not provide both assetId and b64.`
        );
      }
    });
  }

  private validateContentBlock(
    block: EvaluationContentBlock | undefined,
    label: string
  ): void {
    if (!block) {
      throw new EvaluationValidationError(`${label} must not be empty.`);
    }
    if (!block.label?.trim()) {
      throw new EvaluationValidationError(`${label} label must not be empty.`);
    }
    const hasContent = !!block.content?.trim();
    const hasMedia = this.hasBlockMedia(block);
    if (!hasContent && !hasMedia) {
      throw new EvaluationValidationError(`${label} content must not be empty.`);
    }
    if (block.media) {
      this.validateMediaItems(block.media, `${label} media`);
    }
  }

  private validateTestCase(testCase: EvaluationTestCase | undefined, label: string): void {
    if (!testCase?.id?.trim()) {
      throw new EvaluationValidationError(`${label} id must not be empty.`);
    }

View on GitHub (pinned to 3e677b1d9f)

Solutions

1. Provide the required input content block object for the entity named in the error message
2. Check where the payload is assembled and assert input exists before submit
3. If input is genuinely optional in your domain, gate the whole evaluation submission on its presence

Example fix

// before
const testCase = { id: 'tc-1' };

// after
const testCase = {
  id: 'tc-1',
  input: { label: 'prompt', content: 'Summarize this text' }
};

if (!testCase.input) throw new Error(`testCase ${testCase.id} has no input block`);

const hasInput = (tc: { input?: unknown }): boolean => !!tc.input && typeof tc.input === 'object';

try {
  await evaluationService.create(request);
} catch (err) {
  if (err instanceof EvaluationValidationError && /must not be empty/.test(err.message)) {
    highlightMissingBlock(err.message);
  } else throw err;
}

When it happens

Trigger: Submitting a test case (or similar entity) whose input field is omitted or explicitly undefined. Validation is reached with block === undefined, e.g. { id: 'tc-1' } with no input.

Common situations: Optional chaining hiding a missing input when constructing payloads; deserializing JSON where input was dropped; schema changes making input optional when the service still requires it.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• ${label} #${index + 1} must provide either assetId or b64.
• ${label} label must not be empty.
• ${label} content must not be empty.
• Result evaluation snapshot testCaseId must match testCase.id
• Image result evaluation requires at least one output image e

AI-assisted analysis of linshenkx/prompt-optimizer@3e677b1d9f (2026-08-27). Data as JSON: /api/errors/abbf92a2aae3146c. Report an issue: GitHub.