# Fix a sync that has been failing silently

A sync that stopped working after an upstream schema change and reported nothing.

Category: Pipelines and warehouse
Source: https://letsship.ai/use-cases/fix-a-silently-failing-sync
Published: 2026-08-25

## Goal

Repair a failing sync and backfill the window it missed.

## Acceptance criteria

- The sync completes successfully
- The missed window is backfilled and row counts are reconciled
- The failure now alerts rather than passing silently
- The upstream change that broke it is described

## What lands as proof

Reconciled row counts across the missed window, plus an alert proven to fire on the failure mode.

## Prompt

Copy this to an agent to open the ticket:

```text
Create a Linear issue in my team and assign it to the SHIP agent.

Title: Fix the {source} sync

Description: Repair a failing sync and backfill the window it missed.

Acceptance criteria:
- The sync completes successfully
- The missed window is backfilled and row counts are reconciled
- The failure now alerts rather than passing silently
- The upstream change that broke it is described

Before you create the issue, check this repository's sync history for sources with no recent successful run and replace {source}.
```

## Questions

### What does the agent actually change?

The ticket is scoped to one outcome: repair a failing sync and backfill the window it missed. Work that serves that outcome is in scope, and anything outside it is left for a separate ticket, so the pull request stays reviewable.

### How do I know the work is done?

The pull request carries the evidence, not only the diff. Here that means sync green and the missed window backfilled, so a reviewer can confirm the result without reproducing the work locally.

### How much oversight does this need?

The run stops once the plan is written. Somebody reads the approach and approves it before any code exists, which is the cheapest moment to redirect the work.