# The Data Pipeline · checkpoint worksheet

## 1 · Actual pipeline map

Client result:  
Source row grain:  
Trusted-table grain:  
Most fragile boundary:  
Test at that boundary:

## 2 · Rerun contract

| Event | Expected rows/state | Mechanism that guarantees it |
|---|---|---|
| First run | | |
| Identical second run | | |
| Interrupted run | | |

Business key / conflict key:  
Transaction boundary:  
Safe retry command:

## 3 · Handoff alarm

Failure to detect:  
Signal and threshold:  
Owner:  
First diagnostic command:  
What distinguishes no new data from a failed refresh?