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Instrument Product Analytics

PostHogOfficialCreated by PostHog

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

Add PostHog product analytics events to track user behavior. Use after implementing new features or reviewing PRs to ensure meaningful user actions are captured. Also handles initial PostHog SDK setup if not yet installed.
— 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 workflow to integrate PostHog product analytics into a wide variety of software projects. It guides the user through detecting the project's framework, installing the appropriate SDK, initializing the service, and strategically placing event capture calls. The skill emphasizes non-intrusive implementation, requiring that new analytics code be added alongside existing logic without altering the project's fundamental architecture. It also covers user identification, error tracking, and secure environment variable management.

What it does

  • Detects the project's framework and language to determine the correct PostHog SDK.
  • Handles initial SDK installation and initialization based on framework-specific patterns.
  • Identifies key user actions and business-critical events for tracking.
  • Implements event capture calls and user identification logic.
  • Configures environment variables securely for API tokens and host URLs.
  • Verifies the integration and performs targeted linting on modified files.

When to use it

  • After implementing new features that require tracking for product analytics.
  • When reviewing pull requests to ensure meaningful user behaviors are captured.
  • During the initial setup of a new project that needs product analytics.
  • When migrating or adding analytics to an existing application.

Advantages

  • Supports a broad range of frontend, backend, and mobile frameworks.
  • Ensures consistent event naming and property usage across the codebase.
  • Prioritizes non-breaking changes and minimal impact on existing code structure.
  • Automates the complex setup of environment variables and SDK initialization.

Usage examples

“Add PostHog analytics to my Next.js project.”
The agent will analyze the project structure, install the PostHog SDK, initialize it in the appropriate client/server files, and prompt you to identify key events to track.
“I need to track user signups and errors in my Django backend.”
The agent will locate your authentication logic, add identify calls, implement exception capture, and ensure the PostHog project tokens are managed via environment variables.

Install

  1. Download the skill as a ZIP:

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

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

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

Documentation by PostHog

Add PostHog product analytics events

Use this skill to add product analytics events (capture calls) that track meaningful user actions in new or changed code. Use it after implementing features or reviewing PRs to ensure key user behaviors are captured. If PostHog is not yet installed, this skill also covers initial SDK setup. Supports any framework or language.

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

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, skip to STEP 5.

STEP 2: Research integration. (Skip if PostHog is already set up.) 2.1. Find the reference file below that matches the detected framework — it is the source of truth for SDK initialization, provider setup, and event capture 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. (Skip if PostHog is already set up.)

  • 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. (Skip if PostHog is already set up.)

  • 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).

STEP 5: Plan event tracking.

  • From the project's file list, select between 10 and 15 files that might have interesting business value for event tracking, especially conversion and churn events.

  • Also look for files related to login that could be used for identifying users, along with error handling.

  • Find any existing posthog.capture() code. Make note of event name formatting. Don't duplicate existing events; supplement them.

  • Track actions only, not pageviews (those can be captured automatically). Exceptions can be made for "viewed"-type events at the top of a conversion funnel.

  • Server-side events are REQUIRED if the project includes any instrumentable server-side code (API routes, server actions, webhook handlers, payment/checkout completion, authentication endpoints).

STEP 6: Implement event capture.

  • For each planned event, add posthog.capture() calls with useful properties.

  • If a file already has existing integration code for other tools or services, don't overwrite or remove that code. Place PostHog code below it.

  • Do not alter the fundamental architecture of existing files. Make additions minimal and targeted.

  • You must read a file immediately before attempting to write it.

STEP 7: Identify users.

  • Add PostHog identify() calls on the client side during login and signup events. Use the contents of login and signup forms to identify users on submit.

  • 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. On the server side, make sure events have a matching distinct ID.

STEP 8: Add error tracking.

  • Add PostHog exception capture error tracking to relevant files, particularly around critical user flows and API boundaries.

STEP 9: 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 using the framework's naming convention.

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

STEP 10: 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-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-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-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/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 docs: Follow the framework reference's initialization and capture patterns exactly.

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-product-analytics · 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-product-analytics.zip