> ## Documentation Index
> Fetch the complete documentation index at: https://brushysuite.gfrancodev.com/llms.txt
> Use this file to discover all available pages before exploring further.

# DependencyError

> DI error types and troubleshooting.

## `DependencyError`

Thrown when resolution fails, most commonly an unregistered token.

```typescript theme={null}
import { DependencyError } from "@brushy/di-core";

try {
  container.resolve(UNKNOWN_TOKEN);
} catch (error) {
  if (error instanceof DependencyError) {
    console.error(error.message);
    // "Token not registered: Symbol(UNKNOWN)"
  }
}
```

| Property  | Value                     |
| --------- | ------------------------- |
| `name`    | `"BrushyDependencyError"` |
| `message` | Human-readable reason     |

In development (`IS_DEV`), errors are also logged through the internal `Logger`.

## Common messages

| Message                                                                | Fix                                                             |
| ---------------------------------------------------------------------- | --------------------------------------------------------------- |
| `Token not registered: …`                                              | Register the token or check parent container import             |
| `No container found. Use registerContainer() or setDefaultContainer()` | Call `inject.setGlobalContainer` or `server.setServerContainer` |
| `No server container defined. Use server.setServerContainer() first.`  | Bootstrap server before `server.resolve`                        |
| `No global container defined. Use inject.setGlobalContainer() first.`  | Bootstrap before `inject.resolve`                               |

## Circular dependencies

The resolver detects dependency cycles and throws with a descriptive `DependencyError` chain. Use `container.observe` or [monitor](/di/monitor/overview) to trace which token triggered the cycle.

## Container `error` events

When observers are attached, failed resolves emit `error` events before re-throwing. See [Container events](/di/di-core/events).