---
title: 'CHR0014: Reducer cannot combine EventStore with explicit event sequence'
---

## Rule Description

A reducer that declares `[EventStore("...")]` must use implicit inbox routing. It cannot also define an explicit event sequence.

## Severity

Error

## Example

### Violation

```csharp
using Cratis.Chronicle.Events;
using Cratis.Chronicle.Reducers;

[EventStore("identity-service")]
[Reducer(eventSequence: "custom-sequence")]
public class UserSummaryReducer : IReducer
{
}
```

### Fix

```csharp
using Cratis.Chronicle.Events;
using Cratis.Chronicle.Reducers;

[EventStore("identity-service")]
[Reducer]
public class UserSummaryReducer : IReducer
{
}
```

## Why This Rule Exists

`[EventStore]` on a reducer is intended to drive outbox-to-inbox routing. Combining it with explicit event sequence configuration creates ambiguous routing intent.

## Related Rules

- [CHR0013](/chronicle/code-analysis/chr0013/): Reactor cannot combine EventStore with explicit event sequence