jackwener/OpenCLI · error · CommandExecutionError

Failed to add @${username} to list ${listId}: member_count u

Error message

Failed to add @${username} to list ${listId}: member_count unchanged and membership was not confirmed

What it means

A CommandExecutionError from buildListAddMemberRow thrown when the member_count did not increase (noop) and the response did not confirm isMember === true. This is the 'add silently did nothing' case: the mutation returned success-shaped data but neither the count nor an explicit membership flag proves the user was added.

Source

Thrown at clis/twitter/list-add-core.js:88

    if (!hasMemberCount) {
        throw new CommandExecutionError(`Failed to add @${username} to list ${listId}: no member_count in response`);
    }

    const memberCountAfter = Number(addResult.mc);
    if (!Number.isFinite(memberCountAfter)) {
        throw new CommandExecutionError(`Failed to add @${username} to list ${listId}: invalid member_count in response`);
    }

    if (memberCountAfter < memberCountBefore) {
        throw new CommandExecutionError(
            `Failed to add @${username} to list ${listId}: member_count decreased unexpectedly (${memberCountBefore} → ${memberCountAfter})`
        );
    }

    const countIncreased = memberCountAfter > memberCountBefore;
    const noop = !countIncreased;
    if (noop && addResult.isMember !== true) {
        throw new CommandExecutionError(
            `Failed to add @${username} to list ${listId}: member_count unchanged and membership was not confirmed`
        );
    }
    const verifiedBy = `member_count ${memberCountBefore} → ${memberCountAfter}`;
    return {
        listId,
        username,
        userId: String(userId),
        status: noop ? 'noop' : 'success',
        message: noop
            ? `@${username} is already a member of list ${listId}`
            : `Added @${username} to list ${listId} (verified via ${verifiedBy})`,
    };
}

export async function listAddUser(page, kwargs) {
        const listId = String(kwargs.listId || '').trim();
        const username = String(kwargs.username || '').replace(/^@/, '').trim();

View on GitHub (pinned to 49907e53dc)

Solutions

1. Check whether @username is already in the list — if so, this add was a no-op and can be skipped.
2. Update the library so isMember is parsed from X's current response schema.
3. Retry once with a fresh session to get a payload that confirms membership explicitly.
4. If you intentionally tolerate duplicates, treat 'already a member' responses as success in your wrapper.

Example fix

// before: blind re-add of an existing member
await listAddUser(page, { listId, username: 'alice' }); // throws
// after: check membership first
const members = await listMembers(page, listId);
if (!members.includes('alice')) await listAddUser(page, { listId, username: 'alice' });

// avoid the error entirely: skip users already in the list
const members = new Set(await listMemberUsernames(page, listId));
const pending = usernames.filter(u => !members.has(u.replace(/^@/, '')));

function confirmsMembership(r) {
  return r?.isMember === true;
}

try {
  await listAddUser(page, { listId, username });
} catch (e) {
  if (/member_count unchanged and membership was not confirmed/.test(e.message)) {
    console.warn(`@${username} may already be in list ${listId}; skipping`);
    return; // treat as idempotent success
  }
  throw e;
}

When it happens

Trigger: countIncreased === false and addResult.isMember !== true after the add — usually because the user was ALREADY a member (count unchanged) but the response also failed to set the isMember flag, or X returned an ambiguous payload.

Common situations: Idempotent re-run adding a user who is already in the list; X's GraphQL response omitting the isMember field due to schema drift; a soft-failed mutation that returned HTTP 200.

Related errors

• Failed to add @${username} to list ${listId}: ${msg.slice(0,
• Failed to add @${username} to list ${listId}: no member_coun
• Failed to add @${username} to list ${listId}: invalid member
• ${probe.detail}
• 12306 whoami failed: ${probe.detail}

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/eb7088680b7fee5d. Report an issue: GitHub.