For the complete documentation index, see llms.txt. Markdown versions of all docs pages are available by appending .md to any docs URL.

LangSmith

Integrate agentgateway with LangSmith for LLM debugging and monitoring

LangSmith is LangChain’s platform for debugging, testing, evaluating, and monitoring LLM applications.

Features

• Trace logging - Detailed request/response logging
• Debugging - Step-through debugging of LLM calls
• Evaluation - Automated testing and evaluation
• Monitoring - Production monitoring and alerting
• Datasets - Build and manage evaluation datasets

Setup

1. Sign up at smith.langchain.com
2. Create a project and get your API key

Configuration

LangSmith accepts OpenTelemetry traces directly. Configure agentgateway to export traces directly to LangSmith:

# yaml-language-server: $schema=https://agentgateway.dev/schema/config
config:
  tracing:
    otlpEndpoint: https://api.smith.langchain.com/otel
    randomSampling: true

binds:
- port: 3000
  listeners:
  - routes:
    - backends:
      - ai:
          name: openai
          provider:
            openAI:
              model: gpt-4o-mini
      policies:
        backendAuth:
          key: "$OPENAI_API_KEY"

Authentication

LangSmith requires an API key for authentication. Set the OTEL_EXPORTER_OTLP_HEADERS environment variable with your LangSmith API key:

# Set the x-api-key header for LangSmith authentication
export OTEL_EXPORTER_OTLP_HEADERS="x-api-key=your-langsmith-api-key"

# Also set the protocol to HTTP/protobuf (LangSmith requires HTTP, not gRPC)
export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf

Docker Compose example

Agentgateway exports traces directly to LangSmith without needing an OTel Collector:

version: '3'
services:
  agentgateway:
    image: ghcr.io/agentgateway/agentgateway:latest
    ports:
      - "3000:3000"
    volumes:
      - ./config.yaml:/etc/agentgateway/config.yaml
    environment:
      - OTEL_EXPORTER_OTLP_HEADERS=x-api-key=${LANGSMITH_API_KEY}
      - OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf

Learn more

• LangSmith Documentation
• OpenTelemetry Integration