mastra-ai/mastra · error

Invalid input: must be an array of message IDs or message ob

Error message

Invalid input: must be an array of message IDs or message objects

What it means

Memory message deletion accepts an array of message IDs (strings) or message objects with `id`. Before creating the delete span, the library validates that the input is an array; anything else (undefined, a single ID string, an object) throws this error immediately.

Source

Thrown at packages/memory/src/index.ts:2819

    return memoryStore.updateMessages({ messages });
  }

  /**
   * Deletes one or more messages
   * @param input - Must be an array containing either:
   *   - Message ID strings
   *   - Message objects with 'id' properties
   * @returns Promise that resolves when all messages are deleted
   */
  public async deleteMessages(
    input: MessageDeleteInput,
    observabilityContext?: Partial<ObservabilityContext>,
  ): Promise<void> {
    // Normalize input to messageIds before creating span to avoid leaking full message objects into traces
    let messageIds: string[];

    if (!Array.isArray(input)) {
      throw new Error('Invalid input: must be an array of message IDs or message objects');
    }

    if (input.length === 0) {
      return;
    }

    messageIds = input.map(item => {
      if (typeof item === 'string') {
        return item;
      } else if (item && typeof item === 'object' && 'id' in item) {
        return item.id;
      } else {
        throw new Error('Invalid input: array items must be strings or objects with an id property');
      }
    });

    const invalidIds = messageIds.filter(id => !id || typeof id !== 'string');
    if (invalidIds.length > 0) {

View on GitHub (pinned to 75dd419e61)

Solutions

1. Wrap the input in an array: deleteMessages([messageId]) or deleteMessages([message])
2. Check that the source of the argument actually resolves to an array before calling
3. Validate the payload shape at the boundary (e.g. with zod) to fail fast with a clearer error

Example fix

// before
await memory.deleteMessages(messageId);

// after
await memory.deleteMessages([messageId]);

function assertMessageIdArray(input: unknown): asserts input is (string | { id: string })[] {
  if (!Array.isArray(input)) throw new TypeError('deleteMessages expects an array of ids or message objects');
}

const isMessageIdArray = (v: unknown): v is (string | { id: string })[] =>
  Array.isArray(v) && v.every(i => typeof i === 'string' || (typeof i === 'object' && i !== null && 'id' in i));

try {
  await memory.deleteMessages(input as any);
} catch (err) {
  if (err instanceof Error && err.message.startsWith('Invalid input')) {
    console.error('deleteMessages input must be an array:', input);
  }
  throw err;
}

When it happens

Trigger: Passing a single string message ID instead of an array; passing undefined/null (e.g. from a variable that failed to populate); passing a single message object instead of [message].

Common situations: Calling deleteMessages(id) with one ID from an older code sample; an upstream query returning undefined that is forwarded directly; TypeScript types bypassed via `any` or JS callers.

Related errors

• Invalid input: array items must be strings or objects with a
• All message IDs must be non-empty strings
• Received input message with wrong threadId. Input ${message.
• Received input message with wrong resourceId. Input ${messag
• Found unhandled message ${JSON.stringify(message)}

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/e6ea52a9c489df3f. Report an issue: GitHub.