# OpenTelemetry LLM Observability Integration

This MCP server now includes comprehensive OpenTelemetry support for LLM observability, compatible with any OpenTelemetry backend including Jaeger, New Relic, Grafana, Datadog, Honeycomb, and more.

## Features

- **Universal Compatibility**: Works with any OpenTelemetry-compatible backend
- **Comprehensive Metrics**: Request counts, token usage, latency, error rates
- **Distributed Tracing**: Full request lifecycle tracking with spans
- **Flexible Configuration**: Environment-based configuration for different backends
- **Zero-Code Integration**: Drop-in replacement for existing observability tools

## Quick Start

### 1. Install Dependencies

The OpenTelemetry dependencies are already included in the package.json:

```bash
npm install
```

### 2. Configure Your Backend

#### Jaeger (Local Development)

```bash
# Start Jaeger locally
docker run -d --name jaeger \
  -e COLLECTOR_OTLP_ENABLED=true \
  -p 16686:16686 \
  -p 4317:4317 \
  -p 4318:4318 \
  jaegertracing/all-in-one:latest

# Configure the MCP server
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
export OTEL_SERVICE_NAME=llm-observability-mcp
```

#### New Relic

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp.nr-data.net:4318
export OTEL_EXPORTER_OTLP_HEADERS="api-key=YOUR_NEW_RELIC_LICENSE_KEY"
export OTEL_SERVICE_NAME=llm-observability-mcp
```

#### Grafana Cloud

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp-gateway-prod-us-central-0.grafana.net/otlp
export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Basic $(echo -n YOUR_INSTANCE_ID:YOUR_API_KEY | base64)"
export OTEL_SERVICE_NAME=llm-observability-mcp
```

#### Datadog

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://api.datadoghq.com/api/v2/series
export OTEL_EXPORTER_OTLP_HEADERS="DD-API-KEY=YOUR_DD_API_KEY"
export OTEL_SERVICE_NAME=llm-observability-mcp
```

### 3. Start the MCP Server

```bash
# Start with stdio transport
npm run mcp:stdio

# Start with HTTP transport
npm run mcp:http
```

## Usage

### Using the OpenTelemetry Tool

The MCP server provides a new tool: `capture_llm_observability_opentelemetry`

#### Required Parameters

- `userId`: The distinct ID of the user
- `model`: The model used (e.g., "gpt-4", "claude-3")
- `provider`: The LLM provider (e.g., "openai", "anthropic")

#### Optional Parameters

- `traceId`: Trace ID for grouping related events
- `input`: The input to the LLM (messages, prompt, etc.)
- `outputChoices`: The output from the LLM
- `inputTokens`: Number of tokens in the input
- `outputTokens`: Number of tokens in the output
- `latency`: Latency of the LLM call in seconds
- `httpStatus`: HTTP status code of the LLM call
- `baseUrl`: Base URL of the LLM API
- `operationName`: Name of the operation being performed
- `error`: Error message if the request failed
- `errorType`: Type of error (e.g., "rate_limit", "timeout")
- `mcpToolsUsed`: List of MCP tools used during the request

### Example Usage

```json
{
  "userId": "user-123",
  "model": "gpt-4",
  "provider": "openai",
  "inputTokens": 150,
  "outputTokens": 75,
  "latency": 2.5,
  "httpStatus": 200,
  "operationName": "chat-completion",
  "traceId": "trace-abc123"
}
```

## Configuration Reference

### Environment Variables

| Variable | Description | Default |
|----------|-------------|---------|
| `OTEL_SERVICE_NAME` | Service name for OpenTelemetry | `llm-observability-mcp` |
| `OTEL_SERVICE_VERSION` | Service version | `1.0.0` |
| `OTEL_ENVIRONMENT` | Environment name | `development` |
| `OTEL_EXPORTER_OTLP_ENDPOINT` | Default OTLP endpoint | - |
| `OTEL_EXPORTER_OTLP_METRICS_ENDPOINT` | Metrics endpoint | - |
| `OTEL_EXPORTER_OTLP_TRACES_ENDPOINT` | Traces endpoint | - |
| `OTEL_EXPORTER_OTLP_LOGS_ENDPOINT` | Logs endpoint | - |
| `OTEL_EXPORTER_OTLP_HEADERS` | Headers for authentication (format: "key1=value1,key2=value2") | - |
| `OTEL_METRIC_EXPORT_INTERVAL` | Metrics export interval in ms | `10000` |
| `OTEL_METRIC_EXPORT_TIMEOUT` | Metrics export timeout in ms | `5000` |
| `OTEL_TRACES_SAMPLER_ARG` | Sampling ratio (0.0-1.0) | `1.0` |

### Backend-Specific Configuration

#### New Relic

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp.nr-data.net:4318
export OTEL_EXPORTER_OTLP_HEADERS="api-key=YOUR_LICENSE_KEY"
```

#### Jaeger

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
```

#### Grafana Cloud

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://otlp-gateway-prod-us-central-0.grafana.net/otlp
export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Basic $(echo -n YOUR_INSTANCE_ID:YOUR_API_KEY | base64)"
```

#### Honeycomb

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://api.honeycomb.io/v1/traces
export OTEL_EXPORTER_OTLP_HEADERS="x-honeycomb-team=YOUR_API_KEY"
```

#### Lightstep

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=https://ingest.lightstep.com:443/api/v2/otel/trace
export OTEL_EXPORTER_OTLP_HEADERS="lightstep-access-token=YOUR_ACCESS_TOKEN"
```

## Metrics Collected

### Counters

- `llm.requests.total`: Total number of LLM requests
- `llm.tokens.total`: Total tokens used (input + output)

### Histograms

- `llm.latency.duration`: Request latency in milliseconds

### Gauges

- `llm.requests.active`: Number of active requests

### Trace Attributes

- `llm.model`: The model used
- `llm.provider`: The provider name
- `llm.user_id`: The user ID
- `llm.operation`: The operation name
- `llm.input_tokens`: Input token count
- `llm.output_tokens`: Output token count
- `llm.total_tokens`: Total token count
- `llm.latency_ms`: Latency in milliseconds
- `llm.http_status`: HTTP status code
- `llm.base_url`: API base URL
- `llm.error`: Error message (if any)
- `llm.error_type`: Error type classification
- `llm.input`: Input content (optional)
- `llm.output`: Output content (optional)
- `llm.mcp_tools_used`: MCP tools used

## Testing with Jaeger

### 1. Start Jaeger

```bash
docker run -d --name jaeger \
  -e COLLECTOR_OTLP_ENABLED=true \
  -p 16686:16686 \
  -p 4317:4317 \
  -p 4318:4318 \
  jaegertracing/all-in-one:latest
```

### 2. Configure MCP Server

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
export OTEL_SERVICE_NAME=llm-observability-mcp
npm run mcp:stdio
```

### 3. View Traces

Open <http://localhost:16686> to view traces in Jaeger UI.

## Migration from PostHog

The OpenTelemetry tool is designed to be a drop-in replacement for the PostHog tool. Both tools can coexist, allowing for gradual migration:

1. **PostHog Tool**: `capture_llm_observability`
2. **OpenTelemetry Tool**: `capture_llm_observability_opentelemetry`

Both tools accept the same parameters, making migration straightforward.

## Troubleshooting

### Common Issues

#### No Data in Backend

1. Verify endpoint URLs are correct
2. Check authentication headers
3. Ensure network connectivity
4. Check server logs for errors

#### High Resource Usage

1. Adjust sampling ratio: `OTEL_TRACES_SAMPLER_ARG=0.1`
2. Increase export intervals: `OTEL_METRIC_EXPORT_INTERVAL=30000`

#### Missing Traces

1. Verify OpenTelemetry is enabled (check for endpoint configuration)
2. Check for initialization errors in logs
3. Ensure proper service name configuration

### Debug Mode

Enable debug logging:

```bash
export DEBUG=true
npm run mcp:stdio
```

## Advanced Configuration

### Custom Headers

```bash
export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Bearer token,Custom-Header=value"
```

### Multiple Backends

Configure different endpoints for metrics and traces:

```bash
export OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=https://metrics.example.com
export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://traces.example.com
```

### Sampling Configuration

```bash
# Sample 10% of traces
export OTEL_TRACES_SAMPLER_ARG=0.1
```

## Support

For issues or questions:

1. Check the troubleshooting section above
2. Review server logs with `DEBUG=true`
3. Verify OpenTelemetry configuration
4. Test with Jaeger locally first