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Instrument Integration

PostHogOfficialCreated by PostHog

  • Skill
  • Tool integration
  • Data and AI
  • MIT
  • Low risk
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From the author

Add PostHog SDK integration to your application. Use when setting up PostHog for the first time or reviewing PRs that need PostHog initialization. Covers SDK installation, provider setup, and basic configuration for any framework.
— the description by PostHog

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured, multi-step procedure for integrating the PostHog SDK into a wide range of web, mobile, and backend frameworks. It handles the detection of the project environment, installation of the appropriate SDK, initialization, user identification, and secure configuration of environment variables. The skill emphasizes following framework-specific patterns and maintaining an analytics contract, ensuring that PostHog is implemented consistently without disrupting existing application logic.

What it does

  • Detects the project's framework, language, and package manager.
  • Installs the correct PostHog SDK for the identified platform.
  • Configures PostHog initialization and provider setup based on framework-specific references.
  • Implements user identification logic for login and signup events.
  • Manages environment variables for project tokens and host URLs securely.
  • Verifies the integration and performs minimal cleanup.

When to use it

  • When setting up PostHog in a project for the first time.
  • When reviewing pull requests that require PostHog initialization.
  • When adding analytics to a new application across supported frameworks.
  • When migrating or updating PostHog configurations in an existing codebase.

Advantages

  • Ensures consistent implementation across diverse technology stacks.
  • Prevents hardcoding of sensitive project tokens and host URLs.
  • Follows established framework-specific best practices and patterns.
  • Minimizes the risk of breaking application boot or build processes.
  • Automates the repetitive aspects of SDK setup and environment configuration.

Usage examples

“Set up PostHog in my Next.js project.”
The agent will detect the Next.js environment, install the PostHog SDK, configure the necessary provider, and set up environment variables in .env.local.
“Integrate PostHog into this Android app.”
The agent will identify the Android/Kotlin structure, initialize PostHog in the Application class, and guide the setup of local.properties for configuration.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/posthog/instrument-integration/download

  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip instrument-integration.zip -d .agents/skills

Documentation by PostHog

Add PostHog SDK integration

Use this skill to add the PostHog SDK to an application. Use it when setting up PostHog for the first time, or reviewing PRs that need PostHog initialization. Covers SDK installation, provider setup, and basic configuration. Supports any framework or language.

Supported frameworks and languages: Next.js, React, React Router, Vue, Nuxt, TanStack Start, SvelteKit, Astro, Angular, Django, Flask, FastAPI, Laravel, PHP, Ruby on Rails, Go, Elixir, Android, iOS, Swift, Flutter, React Native, Expo, Node.js, and vanilla JavaScript.

Instructions

Follow these steps IN ORDER:

STEP 1: Analyze the codebase and detect the platform.

Look for dependency files (package.json, pubspec.yaml, Podfile, Package.swift, requirements.txt, Gemfile, composer.json, go.mod, mix.exs, etc.) to determine the framework and language.

Look for lockfiles (pnpm-lock.yaml, package-lock.json, yarn.lock, bun.lockb, go.sum, pubspec.lock, Podfile.lock, Package.resolved, mix.lock) to determine the package manager.

  • Check for existing PostHog setup. If PostHog is already installed and initialized, do not modify its code. Inform the user and skip to verification.

STEP 2: Research integration. 2.1. Find the reference file below that matches the detected framework — it is the source of truth for SDK initialization, provider setup, and configuration patterns. Read it now. 2.2. If no reference matches, fall back to your general knowledge and web search. Use posthog.com/docs as the primary search source.

STEP 3: Install the PostHog SDK.

  • Add the PostHog SDK package for the detected platform. Do not manually edit package.json — use the package manager's install command.

STEP 4: Initialize PostHog.

  • Follow the framework reference for where and how to initialize. This varies significantly by framework (e.g., instrumentation-client.ts for Next.js 15.3+, AppConfig.ready() for Django, create_app() for Flask).

  • Set up the PostHog provider/wrapper component if the framework requires one.

STEP 5: Identify users.

  • Add PostHog identify() calls on the client side during login and signup events.

  • If both frontend and backend exist, pass the client-side session and distinct ID using X-POSTHOG-DISTINCT-ID and X-POSTHOG-SESSION-ID headers to the server-side code.

STEP 6: Set up environment variables.

  • Check if the project already has PostHog environment variables configured (e.g. in .env, .env.local, or framework-specific env files). If valid values already exist, skip this step.

  • If the PostHog project token is missing, use the PostHog MCP server's projects-get tool to retrieve the project's api_token. If multiple projects are returned, ask the user which project to use. If the MCP server is not connected or not authenticated, ask the user for their PostHog project token instead.

  • For the PostHog host URL: check the projects-get MCP response for a region field — US maps to https://us.i.posthog.com, EU maps to https://eu.i.posthog.com. If the region is not available from the MCP response or from existing project configuration, ask the user: "Are you on PostHog US Cloud or EU Cloud?" Do not assume US Cloud.

  • Write these values to the appropriate env file (e.g. .env.local for Next.js, .env for others) using the framework's naming convention.

  • Reference these environment variables in code instead of hardcoding them.

STEP 7: Verify and clean up.

  • Check the project for errors. Look for type checking or build scripts in package.json.

  • Ensure any components created were actually used.

  • Run any linter or prettier-like scripts found in the package.json, but ONLY on the files you have edited or created during this session. Never run formatting or linting across the entire project's codebase.

Reference files

  • references/EXAMPLE-next-app-router.md - next-app-router example project code

  • references/EXAMPLE-next-pages-router.md - next-pages-router example project code

  • references/EXAMPLE-react-react-router-6.md - react-react-router-6 example project code

  • references/EXAMPLE-react-react-router-7-framework.md - react-react-router-7-framework example project code

  • references/EXAMPLE-react-react-router-7-data.md - react-react-router-7-data example project code

  • references/EXAMPLE-react-react-router-7-declarative.md - react-react-router-7-declarative example project code

  • references/EXAMPLE-react-vite.md - react-vite example project code

  • references/EXAMPLE-nuxt-3-6.md - nuxt-3-6 example project code

  • references/EXAMPLE-nuxt-4.md - nuxt-4 example project code

  • references/EXAMPLE-vue-3.md - vue-3 example project code

  • references/EXAMPLE-react-tanstack-router-file-based.md - react-tanstack-router-file-based example project code

  • references/EXAMPLE-react-tanstack-router-code-based.md - react-tanstack-router-code-based example project code

  • references/EXAMPLE-tanstack-start.md - tanstack-start example project code

  • references/EXAMPLE-sveltekit.md - sveltekit example project code

  • references/EXAMPLE-astro-static.md - astro-static example project code

  • references/EXAMPLE-astro-view-transitions.md - astro-view-transitions example project code

  • references/EXAMPLE-astro-ssr.md - astro-ssr example project code

  • references/EXAMPLE-astro-hybrid.md - astro-hybrid example project code

  • references/EXAMPLE-angular.md - angular example project code

  • references/EXAMPLE-javascript-node.md - javascript-node example project code

  • references/EXAMPLE-javascript-web.md - javascript-web example project code

  • references/EXAMPLE-django.md - django example project code

  • references/EXAMPLE-flask.md - flask example project code

  • references/EXAMPLE-fastapi.md - fastapi example project code

  • references/EXAMPLE-python.md - python example project code

  • references/EXAMPLE-laravel.md - laravel example project code

  • references/EXAMPLE-php.md - php example project code

  • references/EXAMPLE-ruby-on-rails.md - ruby-on-rails example project code

  • references/EXAMPLE-ruby.md - ruby example project code

  • references/EXAMPLE-android.md - android example project code

  • references/EXAMPLE-swift.md - swift example project code

  • references/EXAMPLE-react-native.md - react-native example project code

  • references/EXAMPLE-expo.md - expo example project code

  • references/next-js.md - Next.js

  • references/react.md - React

  • references/react-router-v6.md - React router v6

  • references/react-router-v7-framework-mode.md - React router v7 framework mode (remix v3)

  • references/react-router-v7-data-mode.md - React router v7 data mode

  • references/react-router-v7-declarative-mode.md - React router v7 declarative mode

  • references/nuxt-js-3-6.md - Nuxt.js (v3.0 to v3.6)

  • references/nuxt-js.md - Nuxt.js

  • references/vue-js.md - Vue.js

  • references/tanstack-start.md - Tanstack start

  • references/svelte.md - Svelte

  • references/astro.md - Astro

  • references/angular.md - Angular

  • references/js.md - JavaScript web

  • references/posthog-js.md - PostHog JavaScript web SDK

  • references/node.md - Node.js

  • references/posthog-node.md - PostHog Node.js SDK

  • references/django.md - Django

  • references/flask.md - Flask

  • references/python.md - Python

  • references/posthog-python.md - PostHog python SDK

  • references/dotnet.md - .net

  • references/elixir.md - Elixir

  • references/go.md - Go

  • references/laravel.md - Laravel

  • references/php.md - Php

  • references/ruby-on-rails.md - Ruby on rails

  • references/ruby.md - Ruby

  • references/android.md - Android

  • references/ios.md - Ios

  • references/usage.md - Ios SDK usage

  • references/configuration.md - Ios SDK configuration

  • references/flutter.md - Flutter

  • references/react-native.md - React native

  • references/identify-users.md - Identify users

  • references/COMMANDMENTS.md - Framework-specific rules the integration must follow

Each framework reference contains SDK-specific installation, initialization, and usage patterns. Find the one matching the user's stack.

Key principles

  • Environment variables: Always use environment variables for PostHog keys. Never hardcode them.

  • Minimal changes: Add PostHog code alongside existing integrations. Don't replace or restructure existing code.

  • Match the example: Your implementation should follow the example project's patterns as closely as possible.

  • Analytics contract: Treat event names, property names, and feature flag keys as part of an analytics contract. Reuse existing names and patterns found in the project. When introducing new ones, make them clear, descriptive, and consistent with existing conventions.

Files

references/EXAMPLE-ruby.md

PostHog ruby Example Project

Repository: https://github.com/PostHog/context-mill Path: example-apps/ruby

README.md

PostHog Ruby Example - CLI Todo App

A simple command-line todo application built with plain Ruby (no frameworks) demonstrating PostHog integration for CLIs, scripts, data pipelines, and non-web Ruby applications.

Purpose

This example serves as:

  • Verification that the context-mill wizard works for plain Ruby projects

  • Reference implementation of PostHog best practices for non-framework Ruby code

  • Working example you can run and modify

Features Demonstrated

  • Instance-based API - Uses PostHog::Client.new(...) for explicit client management

  • Proper shutdown - Uses shutdown in ensure block to flush events before exit

  • Event tracking - Captures user actions with distinct_id and properties

  • User identification - Associates properties with users via identify

  • Error handling - Manual exception capture for handled errors

Quick Start

1. Install Dependencies
# Install bundler if needed
gem install bundler

# Install dependencies
bundle install
2. Configure PostHog
# Copy environment template
cp .env.example .env

# Edit .env and add your PostHog project token
# POSTHOG_PROJECT_TOKEN=phc_your_project_token_here
# POSTHOG_HOST=https://us.i.posthog.com
3. Run the App
# Add a todo
ruby todo.rb add "Buy groceries"

# List all todos
ruby todo.rb list

# Complete a todo
ruby todo.rb complete 1

# Delete a todo
ruby todo.rb delete 1

# Show statistics
ruby todo.rb stats

What Gets Tracked

The app tracks these events in PostHog:

EventPropertiesPurpose
todo_addedtodo_id, todo_length, total_todosWhen user adds a new todo
todos_viewedtotal_todos, completed_todosWhen user lists todos
todo_completedtodo_id, time_to_complete_hoursWhen user completes a todo
todo_deletedtodo_id, was_completedWhen user deletes a todo
stats_viewedtotal_todos, completed_todos, pending_todosWhen user views stats

Code Structure

example-apps/ruby/
├── todo.rb              # Main CLI application
├── Gemfile              # Ruby dependencies
├── .env.example         # Environment variable template
├── .gitignore           # Git ignore rules
└── README.md            # This file

Key Implementation Patterns

1. Instance-Based Initialization
require 'posthog-ruby'

posthog = PostHog::Client.new(
  api_key: api_key,
  host: 'https://us.i.posthog.com',
  on_error: proc { |status, msg| puts "PostHog error: #{status} - #{msg}" }
)
2. Event Tracking Pattern
# Track events with distinct_id
posthog.capture(
  distinct_id: 'user_123',
  event: 'event_name',
  properties: { key: 'value' }
)
3. Proper Shutdown
begin
  # Your application code
ensure
  # Always call shutdown to flush events and close connections
  posthog&.shutdown
end
4. Identifying Users
# Identify users (optional - adds user properties)
posthog.identify(
  distinct_id: 'user_123',
  properties: { email: '[email protected]', plan: 'pro' }
)

Running Without PostHog

The app works fine without PostHog configured - it simply won't track analytics. You'll see a warning message but the app continues to function normally.

Next Steps

  • Modify todo.rb to experiment with PostHog tracking

  • Add new commands and track their usage

  • Explore feature flags: posthog.is_feature_enabled('flag-name', 'user_id')

  • Check your PostHog dashboard to see tracked events

Learn More

.env.example

# PostHog Configuration
POSTHOG_PROJECT_TOKEN=phc_your_project_token_here
POSTHOG_HOST=https://us.i.posthog.com

# Optional: Enable debug mode to see PostHog requests
# POSTHOG_DEBUG=true

Gemfile

source 'https://rubygems.org'

gem 'posthog-ruby', '~> 3.3'
gem 'dotenv', '~> 3.0'

todo.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

# Simple CLI Todo App with PostHog Analytics
#
# A minimal plain Ruby CLI application demonstrating PostHog integration
# for non-framework Ruby projects (CLIs, scripts, data pipelines, etc.).

require 'json'
require 'securerandom'
require 'time'
require 'dotenv/load'
require 'posthog'

# Data file location
DATA_FILE = File.join(Dir.home, '.todo_app.json')

def initialize_posthog
  # Initialize PostHog with instance-based API.
  # Returns PostHog client or nil if project token not configured.
  project_token = ENV['POSTHOG_PROJECT_TOKEN']

  unless project_token
    puts 'WARNING: PostHog not configured (POSTHOG_PROJECT_TOKEN not set)'
    puts '         App will work but analytics won\'t be tracked'
    return nil
  end

  PostHog::Client.new(
    api_key: project_token,
    host: ENV.fetch('POSTHOG_HOST', 'https://us.i.posthog.com'),
    on_error: proc { |status, msg| puts "PostHog error: #{status} - #{msg}" }
  )
end

def get_user_id
  # Get or create a user ID for this installation.
  # Uses a UUID stored in the data file to represent this user.
  if File.exist?(DATA_FILE)
    data = JSON.parse(File.read(DATA_FILE))
    return data['user_id'] if data['user_id']
  end

  "user_#{SecureRandom.hex(4)}"
end

def load_todos
  # Load todos from disk.
  return { 'user_id' => get_user_id, 'todos' => [] } unless File.exist?(DATA_FILE)

  JSON.parse(File.read(DATA_FILE))
end

def save_todos(data)
  # Save todos to disk.
  File.write(DATA_FILE, JSON.pretty_generate(data))
end

def track_event(posthog, event_name, properties = {})
  # Track an event with PostHog.
  return unless posthog

  posthog.capture(
    distinct_id: get_user_id,
    event: event_name,
    properties: properties
  )
end

def cmd_add(text, posthog)
  # Add a new todo item.
  data = load_todos

  todo = {
    'id' => data['todos'].length + 1,
    'text' => text,
    'completed' => false,
    'created_at' => Time.now.iso8601
  }

  data['todos'] << todo
  save_todos(data)

  puts "Added todo ##{todo['id']}: #{todo['text']}"

  track_event(posthog, 'todo_added', {
    'todo_id' => todo['id'],
    'todo_length' => todo['text'].length,
    'total_todos' => data['todos'].length
  })
end

def cmd_list(posthog)
  # List all todos.
  data = load_todos

  if data['todos'].empty?
    puts "No todos yet! Add one with: ruby todo.rb add 'Your task'"
    return
  end

  puts "\nYour Todos (#{data['todos'].length} total):\n\n"

  data['todos'].each do |todo|
    status = todo['completed'] ? 'X' : ' '
    puts "  [#{status}] ##{todo['id']}: #{todo['text']}"
  end

  puts

  track_event(posthog, 'todos_viewed', {
    'total_todos' => data['todos'].length,
    'completed_todos' => data['todos'].count { |t| t['completed'] }
  })
end

def cmd_complete(id, posthog)
  # Mark a todo as completed.
  data = load_todos

  todo = data['todos'].find { |t| t['id'] == id }

  unless todo
    puts "ERROR: Todo ##{id} not found"
    return
  end

  if todo['completed']
    puts "Todo ##{id} is already completed"
    return
  end

  todo['completed'] = true
  todo['completed_at'] = Time.now.iso8601
  save_todos(data)

  puts "Completed todo ##{todo['id']}: #{todo['text']}"

  time_to_complete = (Time.parse(todo['completed_at']) - Time.parse(todo['created_at'])) / 3600.0

  track_event(posthog, 'todo_completed', {
    'todo_id' => todo['id'],
    'time_to_complete_hours' => time_to_complete
  })
end

def cmd_delete(id, posthog)
  # Delete a todo.
  data = load_todos

  todo = data['todos'].find { |t| t['id'] == id }

  unless todo
    puts "ERROR: Todo ##{id} not found"
    return
  end

  data['todos'].delete(todo)
  save_todos(data)

  puts "Deleted todo ##{id}"

  track_event(posthog, 'todo_deleted', {
    'todo_id' => todo['id'],
    'was_completed' => todo['completed']
  })
end

def cmd_stats(posthog)
  # Show usage statistics.
  data = load_todos

  total = data['todos'].length
  completed = data['todos'].count { |t| t['completed'] }
  pending = total - completed

  puts "\nStats:\n\n"
  puts "  Total todos:     #{total}"
  puts "  Completed:       #{completed}"
  puts "  Pending:         #{pending}"
  puts "  Completion rate: #{total > 0 ? format('%.1f', completed.to_f / total * 100) : '0.0'}%"
  puts

  track_event(posthog, 'stats_viewed', {
    'total_todos' => total,
    'completed_todos' => completed,
    'pending_todos' => pending
  })
end

def print_usage
  puts <<~USAGE
    Simple todo app with PostHog analytics

    Usage:
      ruby todo.rb add "Todo text"    Add a new todo
      ruby todo.rb list               List all todos
      ruby todo.rb complete <id>      Mark todo as completed
      ruby todo.rb delete <id>        Delete a todo
      ruby todo.rb stats              Show statistics
  USAGE
end

# Main entry point
posthog = nil

begin
  posthog = initialize_posthog

  command = ARGV[0]

  unless command
    print_usage
    exit 0
  end

  case command
  when 'add'
    text = ARGV[1]
    unless text
      puts 'ERROR: Please provide todo text'
      puts 'Usage: ruby todo.rb add "Your task"'
      exit 1
    end
    cmd_add(text, posthog)
  when 'list'
    cmd_list(posthog)
  when 'complete'
    id = ARGV[1]&.to_i
    unless id && id > 0
      puts 'ERROR: Please provide a valid todo ID'
      puts 'Usage: ruby todo.rb complete <id>'
      exit 1
    end
    cmd_complete(id, posthog)
  when 'delete'
    id = ARGV[1]&.to_i
    unless id && id > 0
      puts 'ERROR: Please provide a valid todo ID'
      puts 'Usage: ruby todo.rb delete <id>'
      exit 1
    end
    cmd_delete(id, posthog)
  when 'stats'
    cmd_stats(posthog)
  else
    puts "ERROR: Unknown command '#{command}'"
    print_usage
    exit 1
  end
rescue StandardError => e
  puts "ERROR: #{e.message}"

  # Manually capture handled errors
  posthog&.capture_exception(e, get_user_id)

  exit 1
ensure
  # IMPORTANT: Always shutdown PostHog to flush events
  posthog&.shutdown
end

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs Python, Needs Node.js

Security

What our scanner noticed· Low risk

  • Instructions that use the network

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by
PostHog
Publisher
PostHog (Official)
Source
PostHog/skills · skills/omnibus/instrument-integration · commit a5d30e7
Licence
MIT License (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by PostHog.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download instrument-integration.zip