## TL;DR

Plaid's ITEM_LOGIN_REQUIRED means the user changed their bank password, so the item needs re-authentication. Send them through Plaid Link update mode, then resume syncing.

## Error

```text
ITEM_LOGIN_REQUIRED on transactions sync after password change
```

## Steps

1. Catch ITEM_LOGIN_REQUIRED on sync calls Expected: the state is detectable.
2. Send the user through Link in update mode for that item Expected: credentials are refreshed.
3. Resume the transactions sync Expected: it succeeds.
4. Alert on repeated login-required states Expected: churn is visible.

## When to use

- ITEM_LOGIN_REQUIRED after a password change
- The bank credentials are stale

## When not to use

- The item is fine (then it is a different error)
- Update mode also fails (then the bank may need full re-link)

## Tool compatibility

- Plaid Link update mode
- Bank data sync

## Variant phrasings

### plaid item_login_required

The user changed their password. Re-auth via Link update mode.

### transactions sync login required

Same: refresh the item's credentials, then resume.

## Why it happens

Passwords change and bank sessions expire; agents treat the item as permanently healthy after the first link.

## Edge cases

- Some banks force re-auth on their own schedule; expect this periodically
- Do not store bank passwords; Link handles them

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_Fx0S1sdG5mbqe09_G_1t-A