# Configuration

## ObservabilityRegistryConfig

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

## ObservabilityInstanceConfig

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

## SerializationOptions

Options for controlling how span data is serialized before export. Use these to customize truncation limits for large payloads.

```typescript
interface SerializationOptions {
  maxStringLength?: number;
  maxDepth?: number;
  maxArrayLength?: number;
  maxObjectKeys?: number;
}
```

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

### Reference

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

### Exporters

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