[CI] (c05eaeb) next-js/15-pages-router-todo

[wizard-ci-bot]

Automated wizard CI run

Trigger ID: c05eaeb
App: next-js/15-pages-router-todo
App directory: apps/next-js/15-pages-router-todo
Workbench branch: wizard-ci-c05eaeb-next-js-15-pages-router-todo
Wizard branch: main
Examples branch: main
PostHog (MCP) branch: master
Timestamp: 2026-01-14T16:15:33.871Z
Duration: 198.5s

[wizard-ci-bot]

Now I have all the information I need. Let me compile the evaluation:

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PR Evaluation Report

Summary

This PR integrates PostHog analytics into a Next.js 15 Pages Router Todo app. It adds client-side PostHog initialization via instrumentation-client.ts, configures a reverse proxy for ad-blocker circumvention, and instruments all CRUD operations with custom events and exception tracking.

Files changed	Lines added	Lines removed
6	+480	-2

Confidence score: 3/5 🤔

• instrumentation-client.ts is incorrect for Pages Router apps: The instrumentation-client.ts file is a Next.js 15.3+ App Router feature and does NOT work with Pages Router. PostHog should be initialized in _app.tsx instead. [CRITICAL]
• Missing posthog.identify() implementation: No user identification is set up, limiting the ability to associate events with specific users. [MEDIUM]
• Automatic pageview tracking not configured: PostHog capture_pageview option is not set, and no manual pageview tracking exists for route changes in Pages Router. [MEDIUM]

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File changes

Filename	Score	Description
components/todos/todo-list.tsx	4/5	Well-structured event tracking for all CRUD operations with error handling and captureException calls
instrumentation-client.ts	2/5	Wrong initialization approach - this file pattern only works with App Router, not Pages Router
next.config.ts	5/5	Correctly configured reverse proxy rewrites for PostHog to bypass ad blockers
package.json	5/5	Correct addition of posthog-js dependency
pnpm-lock.yaml	5/5	Lock file properly updated with all transitive dependencies
posthog-setup-report.md	3/5	Well-documented but incorrectly claims instrumentation-client.ts works for Pages Router

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App sanity check: 2/5 ❌

Criteria	Result	Description
App builds and runs	No	instrumentation-client.ts won't be auto-loaded in Pages Router - PostHog will NOT initialize
Preserves existing env vars & configs	Yes	Existing code structure preserved, new env vars added
No syntax or type errors	Yes	All TypeScript is syntactically correct
Correct imports/exports	Yes	Imports are valid
Minimal, focused changes	Yes	Changes are appropriately scoped to PostHog integration

Issues

• Wrong initialization pattern for Pages Router: instrumentation-client.ts is an App Router (Next.js 15.3+) feature that relies on the app directory's automatic loading mechanism. Pages Router apps require PostHog initialization in _app.tsx. The current implementation means PostHog will not initialize at all and no events will be captured. Move initialization to _app.tsx using a useEffect hook or PostHogProvider pattern. [CRITICAL]
• .env file committed to repository: The .env file contains the PostHog API key and is included in the PR. While PostHog public keys are not secrets, committing .env files is generally poor practice. Consider using .env.example instead. [LOW]

Other completed criteria

• TypeScript types are properly used
• Error handling preserves existing console.error behavior
• No breaking changes to existing UI components
• reactStrictMode: true and skipTrailingSlashRedirect: true are appropriate additions

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PostHog implementation: 2/5 ❌

Criteria	Result	Description
PostHog SDKs installed	Yes	posthog-js@^1.321.1 added to dependencies
PostHog client initialized	No	instrumentation-client.ts will NOT be loaded in Pages Router - initialization is non-functional
capture()	Yes	Multiple posthog.capture() calls implemented for all CRUD operations
identify()	No	No posthog.identify() calls to associate events with users
Error tracking	Yes	posthog.captureException() called in all catch blocks with capture_exceptions: true
Reverse proxy	Yes	Properly configured in next.config.ts with rewrites to /ingest

Issues

• PostHog will not initialize: The instrumentation-client.ts approach does not work with Pages Router. PostHog must be initialized in _app.tsx. Without initialization, all posthog.capture() calls in todo-list.tsx will be no-ops. [CRITICAL]
• No pageview tracking: Automatic pageview capture is not configured (capture_pageview option not set), and there's no manual pageview tracking for route changes via Next.js Router events. [MEDIUM]
• No user identification: posthog.identify() is never called. Without identification, all events appear as anonymous users, limiting analytics value. [MEDIUM]
• NEXT_PUBLIC_POSTHOG_HOST env var unused: The instrumentation-client.ts hardcodes api_host: "/ingest" but the setup report claims it uses NEXT_PUBLIC_POSTHOG_HOST. This inconsistency is confusing. [LOW]

Other completed criteria

• Exception tracking enabled via capture_exceptions: true
• Debug mode correctly configured for development
• defaults: '2025-05-24' option included
• Reverse proxy correctly routes to US PostHog instance
• No PII captured in event properties

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PostHog insights and events: 4/5 ✅

Filename	PostHog events	Description
todo-list.tsx	todo_created, todo_completed, todo_uncompleted, todo_deleted	Core user actions tracked - enables funnel analysis (create → complete), engagement metrics, and deletion patterns
todo-list.tsx	todos_fetch_failed, todo_create_failed, todo_update_failed, todo_delete_failed	Error tracking events with error messages - enables reliability monitoring
todo-list.tsx	captureException (4 locations)	Unhandled exceptions captured for error tracking dashboard

Issues

• Events won't actually be captured: Due to the initialization issue, these well-designed events will never reach PostHog. [CRITICAL]
• Missing pageview events: No `` events captured, limiting session analysis. [MEDIUM]

Other completed criteria

• Events represent real user actions (create, complete, delete todos)
• Properties include relevant context (todo_id, has_description, error)
• Error events paired with success events for conversion analysis
• Events follow consistent naming convention (todo_<action>, todo_<action>_failed)
• No PII in event properties

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Reviewed by wizard workbench PR evaluator