Yeachan-Heo/oh-my-codex · error

answers[${entry.index}].answer must select exactly one optio

Error message

answers[${entry.index}].answer must select exactly one option

What it means

An option-kind answer must contain exactly one selected value and exactly one selected label. Zero selections or more than one throws this error.

Source

Thrown at src/question/state.ts:387

  if (answer.kind === 'other') {
    if (!question.allow_other) throw new Error(`answers[${entry.index}].answer.kind=other is not allowed for this question`);
    if (multi) throw new Error(`answers[${entry.index}].answer.kind=other is only valid for single-answerable questions`);
    if (!otherText) throw new Error(`answers[${entry.index}].answer.other_text must be a non-empty string`);
    if (selectedValues.length !== 1 || selectedValues[0] !== otherText || answer.value !== otherText) {
      throw new Error(`answers[${entry.index}].answer other value must match selected_values[0] and other_text`);
    }
    assertSelectedLabelsMatch(
      selectedLabels,
      [question.other_label],
      `answers[${entry.index}].answer.selected_labels`,
    );
    return;
  }

  if (answer.kind === 'option') {
    if (multi) throw new Error(`answers[${entry.index}].answer.kind=option is only valid for single-answerable questions`);
    if (selectedValues.length !== 1 || selectedLabels.length !== 1) {
      throw new Error(`answers[${entry.index}].answer must select exactly one option`);
    }
    const selectedValue = selectedValues[0]!;
    if (!optionValues.has(selectedValue)) {
      throw new Error(`answers[${entry.index}].answer selected value is not in the option schema: ${selectedValue}`);
    }
    if (answer.value !== selectedValue) {
      throw new Error(`answers[${entry.index}].answer.value must match selected_values[0]`);
    }
    assertSelectedLabelsMatch(
      selectedLabels,
      expectedSelectedLabelsForValues(question, selectedValues, undefined),
      `answers[${entry.index}].answer.selected_labels`,
    );
    return;
  }

  if (!multi) throw new Error(`answers[${entry.index}].answer.kind=multi is only valid for multi-answerable questions`);
  if (!Array.isArray(answer.value)) throw new Error(`answers[${entry.index}].answer.value must be an array for multi answers`);

View on GitHub (pinned to 3ad79a8a6f)

Solutions

1. Disable submit until exactly one option is chosen for option-kind answers
2. Reset/clear selection state when the question changes so old selections don't accumulate

Example fix

// before
if (selection.length >= 1) submit({ kind: 'option', selected_values: selection });
// after
if (selection.length === 1) submit({ kind: 'option', selected_values: selection, selected_labels: labels });
else showError('Pick exactly one option');

if (answer.kind === 'option' && (answer.selected_values.length !== 1 || answer.selected_labels.length !== 1)) throw new Error('pick exactly one');

function exactlyOne(arr: unknown[]): boolean { return arr.length === 1; }

try { await submit(p, answers); } catch (e) { if (/must select exactly one option/.test((e as Error).message)) { blockSubmitUntilOneSelected(); return; } throw e; }

When it happens

Trigger: kind 'option' with selected_values.length !== 1 or selected_labels.length !== 1, e.g. submitting with nothing selected, or two values stuffed into a single-select answer.

Common situations: Submit button enabled with no selection; single-select widget accidentally accumulating multiple selections; porting a multi-select UI onto an option-kind payload.

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

• ${path} must be a non-empty string array
• selected value is not in the option schema: ${value}
• ${path} cardinality must match selected values
• ${path}[${mismatchIndex}] must match the selected value labe
• answers[${entry.index}].question_id is unknown for this ques

AI-assisted analysis of Yeachan-Heo/oh-my-codex@3ad79a8a6f (2026-08-27). Data as JSON: /api/errors/82435f34116c6ea9. Report an issue: GitHub.