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.

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 docs references/react router v6.md React router v6 docs references/react router v7 framework mode.md React router v7 framework mode (remix v3) docs references/react router v7 data mode.md React router v7 data mode docs references/react router v7 declarative mode.md React router v7 declarative mode docs references/nuxt js 3 6.md Nuxt.js (v3.0 to v3.6) docs references/nuxt js.md Nuxt.js docs references/vue js.md Vue.js docs references/tanstack start.md Tanstack start docs references/svelte.md Svelte docs references/astro.md Astro docs references/angular.md Angular docs references/django.md Django docs references/flask.md Flask docs references/python.md Python docs references/posthog python.md PostHog python SDK references/dotnet.md .net docs references/elixir.md Elixir docs references/go.md Go docs references/laravel.md Laravel docs references/php.md Php docs references/ruby on rails.md Ruby on rails docs references/ruby.md Ruby docs references/android.md Android docs references/ios.md Ios docs references/usage.md Ios SDK usage docs references/configuration.md Ios SDK configuration docs references/flutter.md Flutter docs references/react native.md React native docs references/identify users.md Identify users docs 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.

instrument-product-analytics