linshenkx/prompt-optimizer · error · VariableExtractionParseError

variables[ ] is not a valid object.

Error message

variables[${index}] is not a valid object.

What it means

While validating each entry of the variables array, entry at position ${index} is null, a primitive, or otherwise not an object. Each extracted variable must be an object with name/value/position fields, so normalization aborts on the first malformed entry and reports its index.

Solutions

1. Log the raw variables array to see the actual shape at the failing index.
2. Fix the prompt/template to require each entry be an object like {name, value, position}.
3. Add a pre-normalization filter/mapper converting shorthand entries: strings -> {name: s, value: '', position: {start: 0, end: 0}}.
4. Switch to a model with stronger instruction-following.

Example fix

// before
return this.normalizeExtractionResponse(parsed);

// after
parsed.variables = parsed.variables.map(v => typeof v === 'string' ? { name: v, value: '', position: { start: 0, end: 0 } } : v).filter(Boolean);
return this.normalizeExtractionResponse(parsed);

const allVariablesAreObjects = (vars: unknown[]): boolean =>
  vars.every(v => !!v && typeof v === 'object' && !Array.isArray(v));

try {
  await extractionService.extract({ modelKey, content });
} catch (e) {
  if (e instanceof VariableExtractionParseError && /is not a valid object/.test(e.message)) {
    // filter/map string entries to objects, then retry
  }
  throw e;
}

When it happens

Trigger: The LLM's variables array contains a null, a string (e.g. just the variable name), or a number at the reported index. Reached via extract() when the model emits a heterogeneous or degenerate array.

Common situations: Model emits variables as a plain string array ("variables": ["user.name", "date"]) instead of objects; model inserts null placeholders; mixed-quality output from a weak model; prompt example showed a shorthand format.

Related errors

• variables[ ] is missing a valid "name" field.
• variables[ ] is missing a valid "value" field.
• Extraction result must have a "summary" string.
• Extraction result must have a "variables" array.
• Extraction result is not a valid object.

AI-assisted analysis of linshenkx/prompt-optimizer@3e677b1d9f (2026-08-27). Data as JSON: /api/errors/b70b9915fc9369b6. Report an issue: GitHub.

Appendix: source

Thrown at packages/core/src/services/variable-extraction/service.ts:211

    if (!data || typeof data !== 'object') {
      throw new VariableExtractionParseError('Extraction result is not a valid object.');
    }

    // 验证 variables 字段
    if (!Array.isArray(data.variables)) {
      throw new VariableExtractionParseError('Extraction result must have a "variables" array.');
    }

    // 验证 summary 字段
    if (typeof data.summary !== 'string') {
      throw new VariableExtractionParseError('Extraction result must have a "summary" string.');
    }

    // 标准化每个变量
    const variables: ExtractedVariable[] = data.variables.map((variable: any, index: number) => {
      // 验证必需字段
      if (!variable || typeof variable !== 'object') {
        throw new VariableExtractionParseError(`variables[${index}] is not a valid object.`);
      }

      if (typeof variable.name !== 'string' || !variable.name.trim()) {
        throw new VariableExtractionParseError(`variables[${index}] is missing a valid "name" field.`);
      }

      if (typeof variable.value !== 'string') {
        throw new VariableExtractionParseError(`variables[${index}] is missing a valid "value" field.`);
      }

      if (!variable.position || typeof variable.position !== 'object') {
        throw new VariableExtractionParseError(`variables[${index}] is missing a valid "position" object.`);
      }

      if (typeof variable.position.originalText !== 'string') {
        throw new VariableExtractionParseError(
          `variables[${index}].position is missing a valid "originalText" field.`
        );

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