# Configuration

## `ObservabilityRegistryConfig`

```typescript
interface ObservabilityRegistryConfig {
  default?: { enabled?: boolean }
  configs?: Record<string, Omit<ObservabilityInstanceConfig, 'name'> | ObservabilityInstance>
  configSelector?: ConfigSelector
}
```

**default** (`{ enabled?: boolean }`): Enable default configuration with DefaultExporter and CloudExporter

**configs** (`Record<string, Omit<ObservabilityInstanceConfig, 'name'> | ObservabilityInstance>`): Named observability instance configurations or pre-instantiated instances

**configSelector** (`ConfigSelector`): Runtime configuration selector function

## `ObservabilityInstanceConfig`

```typescript
interface ObservabilityInstanceConfig {
  name: string
  serviceName: string
  sampling?: SamplingStrategy
  exporters?: ObservabilityExporter[]
  spanOutputProcessors?: SpanOutputProcessor[]
  includeInternalSpans?: boolean
  requestContextKeys?: string[]
  serializationOptions?: SerializationOptions
}
```

**name** (`string`): Configuration identifier

**serviceName** (`string`): Service name in traces

**sampling** (`SamplingStrategy`): Sampling configuration (defaults to ALWAYS)

**exporters** (`ObservabilityExporter[]`): Trace data exporters

**spanOutputProcessors** (`SpanOutputProcessor[]`): Span output processors

**includeInternalSpans** (`boolean`): Include spans internal to Mastra operations

**requestContextKeys** (`string[]`): RequestContext keys to extract as metadata (supports dot notation)

**serializationOptions** (`SerializationOptions`): Options for controlling serialization of span data (input/output/attributes)

**serializationOptions.maxStringLength** (`number`): Maximum length for string values (default: 1024)

**serializationOptions.maxDepth** (`number`): Maximum depth for nested objects (default: 6)

**serializationOptions.maxArrayLength** (`number`): Maximum number of items in arrays (default: 50)

**serializationOptions.maxObjectKeys** (`number`): Maximum number of keys in objects (default: 50)

## `SamplingStrategy`

```typescript
type SamplingStrategy =
  | { type: 'always' }
  | { type: 'never' }
  | { type: 'ratio'; probability: number }
  | { type: 'custom'; sampler: (options?: TracingOptions) => boolean }
```

## `ConfigSelector`

```typescript
type ConfigSelector = (
  options: ConfigSelectorOptions,
  availableConfigs: ReadonlyMap<string, ObservabilityInstance>,
) => string | undefined
```

## `ConfigSelectorOptions`

```typescript
interface ConfigSelectorOptions {
  requestContext?: RequestContext
}
```

## Registry methods

The Observability class provides methods for managing observability instances:

### `registerInstance`

```typescript
registerInstance(
  name: string,
  instance: ObservabilityInstance,
  isDefault?: boolean
): void;
```

Registers an observability instance in the registry.

### `getInstance`

```typescript
getInstance(name: string): ObservabilityInstance | undefined;
```

Retrieves an observability instance by name.

### `getDefaultInstance`

```typescript
getDefaultInstance(): ObservabilityInstance | undefined;
```

Returns the default observability instance.

### `getSelectedInstance`

```typescript
getSelectedInstance(
  options: ConfigSelectorOptions
): ObservabilityInstance | undefined;
```

Returns the observability instance selected by the config selector or default.

### `listInstances`

```typescript
listInstances(): ReadonlyMap<string, ObservabilityInstance>;
```

Returns all registered observability instances.

### `hasInstance`

```typescript
hasInstance(name: string): boolean;
```

Checks if an observability instance exists.

### `setConfigSelector`

```typescript
setConfigSelector(selector: ConfigSelector): void;
```

Sets the config selector function.

### `unregisterInstance`

```typescript
unregisterInstance(name: string): boolean;
```

Removes an observability instance from the registry.

### clear

```typescript
clear(): void;
```

Clears all instances without shutdown.

### shutdown

```typescript
async shutdown(): Promise<void>;
```

Shuts down all observability instances and clears the registry.

## See also

### Documentation

- [Tracing Overview](https://mastra.ai/docs/observability/tracing/overview) - Concepts and usage guide
- [Sampling Strategies](https://mastra.ai/docs/observability/tracing/overview) - Sampling configuration details
- [Multi-Config Setup](https://mastra.ai/docs/observability/tracing/overview) - Using multiple configurations

### Reference

- [Tracing Classes](https://mastra.ai/reference/observability/tracing/instances) - Core tracing classes
- [Interfaces](https://mastra.ai/reference/observability/tracing/interfaces) - Type definitions
- [Spans Reference](https://mastra.ai/reference/observability/tracing/spans) - Span lifecycle

### Exporters

- [DefaultExporter](https://mastra.ai/reference/observability/tracing/exporters/default-exporter) - Storage configuration
- [CloudExporter](https://mastra.ai/reference/observability/tracing/exporters/cloud-exporter) - Cloud setup
- [Braintrust](https://mastra.ai/reference/observability/tracing/exporters/braintrust) - Braintrust integration
- [Langfuse](https://mastra.ai/reference/observability/tracing/exporters/langfuse) - Langfuse integration
- [LangSmith](https://mastra.ai/reference/observability/tracing/exporters/langsmith) - LangSmith integration