laminar

Laminar AI Observability and Evaluation Platform - Cursor Rules

Overview

Laminar is an open-source platform for observability and evaluations of AI applications. It provides comprehensive LLM tracing based on OpenTelemetry, powerful evaluation tools.

Always Follow These Patterns:

• Analyze the project structure and initialize Laminar once at application entry point with Laminar.initialize()
• Use environment variables for API keys (LMNR_PROJECT_API_KEY)
• Prefer automatic instrumentation over manual when possible
• Use @observe() decorator for custom function tracing in Python
• Use observe() wrapper for custom function tracing in JavaScript/TypeScript
• Call Laminar.shutdown() in JavaScript/TypeScript before process exit if it is a single script
• Group related spans into traces using parent spans
• Use sessions to group related traces for user interactions
• If needed add user IDs and metadata for comprehensive tracking

Installation & Setup

JavaScript/TypeScript

npm add @lmnr-ai/lmnr

Python

pip install 'lmnr[all]'

Environment Variables

LMNR_PROJECT_API_KEY=your_project_api_key_here

Initialization Patterns

JavaScript/TypeScript - Standard Setup

import { Laminar } from '@lmnr-ai/lmnr';

Laminar.initialize({
  projectApiKey: process.env.LMNR_PROJECT_API_KEY
});

// At application exit if a single script
await Laminar.shutdown();

Next.js Setup - instrumentation.ts

export async function register() {
  if (process.env.NEXT_RUNTIME === 'nodejs') {
    const { Laminar } = await import('@lmnr-ai/lmnr');
    Laminar.initialize({
      projectApiKey: process.env.LMNR_PROJECT_API_KEY,
    });
  }
}

Next.js Configuration - next.config.ts

const nextConfig = {
  experimental: {
    serverExternalPackages: ['@lmnr-ai/lmnr']
  }
};
module.exports = nextConfig;

Python Setup

from lmnr import Laminar
import os

Laminar.initialize(
    project_api_key=os.environ["LMNR_PROJECT_API_KEY"]
)