Posthog Debugger
PostHogOfficialPublished by PostHog
- Skill
- Review and audit
- Data and AI
- MIT
- No issues found
AutoGineer summary
Written by AutoGineer from the skill’s own files, not by the author
The PostHog Debugger is a diagnostic skill designed to inspect how PostHog is integrated into a web application. It automates the process of navigating to a target URL, enabling debug mode, and extracting configuration details, network activity, and feature flag states. By leveraging browser automation tools, it provides a structured audit of the tracking setup, helping developers identify configuration errors, verify data capture, and detect other third-party analytics tools present on the page.
What it does
- Navigates to specified URLs with PostHog debug parameters enabled.
- Inspects the global window object and bundled configurations for PostHog settings.
- Analyzes network traffic to verify event, session recording, and feature flag endpoints.
- Detects common implementation issues like duplicate instances or disabled autocapture.
- Identifies other third-party analytics and marketing scripts running on the page.
- Generates a structured summary report of the PostHog implementation status.
When to use it
- When you need to verify if PostHog is correctly capturing events on a specific page.
- When troubleshooting missing data or misconfigured feature flags.
- When auditing a website to see which analytics and tracking tools are active.
- When you need to confirm if a site is using a custom proxy or specific cloud region for PostHog.
Advantages
- Provides a standardized, readable report of complex tracking configurations.
- Automates the manual steps of checking console logs and network requests.
- Handles both standard global implementations and complex bundled setups.
- Includes diagnostic checks for common pitfalls like production debug mode or opt-outs.
Usage examples
- “How is PostHog implemented on https://example.com?”
- The agent navigates to the URL, runs diagnostic scripts, and returns a detailed report covering the PostHog version, API host, active features, and detected network activity.
- “Check if session recording is working on my dashboard.”
- The agent inspects the configuration and network requests to confirm if the session recording module is loaded and actively sending data to the server.
Install
Download the skill as a ZIP:
https://mp-staging.autogineer.com/agent-skills/posthog/posthog-debugger/downloadUnzip it into the cross-client skills folder of your project:
mkdir -p .agents/skills && unzip posthog-debugger.zip -d .agents/skills
Documentation by PostHog
PostHog Debugger
Inspect and debug PostHog implementations on any website using browser automation tools. This skill helps developers and product teams understand exactly how PostHog is configured and what data is being captured.
Critical Rules
Always ask for the URL first if not provided.
Always ask if the page requires login. If yes, guide the user to log in via Chrome first.
Use browser tools to navigate and inspect. Prefer Chrome DevTools MCP (
mcp__chrome-devtools__*) or Playwright MCP (mcp__playwright__*) tools.Check multiple signals. PostHog can be implemented in various ways - check scripts, network requests, and the window object.
Report findings clearly. Summarize what you find in a structured format.
Never modify anything. This is read-only inspection.
Initial Flow
When a user asks to inspect a PostHog implementation:
Get the URL (if not provided)
Navigate to the URL with
?__posthog_debug=trueappendedCheck if login is required by taking a snapshot and looking for login indicators
If login required, ask the user to authenticate in the browser
Once authenticated, proceed with inspection
Detecting Login Pages
After navigating, take a snapshot and look for login indicators:
Page title contains "login", "sign in", "authenticate"
URL contains "login", "signin", "auth", "sso"
Page has username/password fields
Page shows "Sign in with Google/GitHub/etc." buttons
Authenticated Pages Workflow
If you detect a login page or the user mentions the page requires auth:
Keep the browser open - you've already navigated there
Ask the user to log in:
"This page requires authentication. Please log in using the Chrome browser I just opened. Let me know when you're logged in and on the page you want to inspect."Once the user confirms, take a new snapshot to verify they're authenticated
Add the debug parameter if not already present and reload if needed
Proceed with inspection
Available Browser Tools
Chrome DevTools MCP
mcp__chrome-devtools__navigate_page- Navigate to URLmcp__chrome-devtools__take_snapshot- Get page accessibility treemcp__chrome-devtools__evaluate_script- Run JavaScript to inspect PostHogmcp__chrome-devtools__list_network_requests- See network trafficmcp__chrome-devtools__get_network_request- Get request detailsmcp__chrome-devtools__list_console_messages- Check for errors
Playwright MCP
mcp__playwright__browser_navigate- Navigate to URLmcp__playwright__browser_snapshot- Get page snapshotmcp__playwright__browser_evaluate- Run JavaScriptmcp__playwright__browser_network_requests- See network trafficmcp__playwright__browser_console_messages- Check console
Inspection Workflow
Step 1: Navigate to the Page with Debug Mode
Always add ?__posthog_debug=true to the URL to enable PostHog's debug mode. This outputs detailed logs to the console.
If URL has no query string:
https://example.com?__posthog_debug=trueIf URL already has query string:
https://example.com?foo=bar&__posthog_debug=true
Workflow:
Navigate to the URL with the debug parameter
Take a snapshot to see what loaded
Check for login page indicators:
URL redirected to
/login,/signin,/auth,/ssoPage title contains "log in", "sign in"
Page has login form fields
If login detected:
Tell the user: "I've opened the page but it requires login. Please log in using Chrome, then let me know when you're ready."
Wait for user confirmation
Take a new snapshot to verify authentication
Add debug parameter to the new URL if needed
If no login needed: Proceed with inspection
Step 2: Check PostHog Global Object
Execute JavaScript to inspect the posthog object on the window:
(() => {
if (typeof posthog === 'undefined') {
return { installed: false };
}
const ph = posthog;
return {
installed: true,
version: ph.version || ph.LIB_VERSION || 'unknown',
config: {
token: ph.config?.token || ph.get_config?.('token') || 'not accessible',
apiHost: ph.config?.api_host || ph.get_config?.('api_host') || 'not accessible',
autocapture: ph.config?.autocapture ?? ph.get_config?.('autocapture') ?? 'not accessible',
capturePageview: ph.config?.capture_pageview ?? ph.get_config?.('capture_pageview') ?? 'not accessible',
capturePageleave: ph.config?.capture_pageleave ?? ph.get_config?.('capture_pageleave') ?? 'not accessible',
sessionRecording: ph.config?.enable_recording_console_log !== undefined ||
ph.sessionRecording?.started ||
'check network',
persistence: ph.config?.persistence || ph.get_config?.('persistence') || 'not accessible',
debug: ph.config?.debug ?? ph.get_config?.('debug') ?? false
},
distinctId: ph.get_distinct_id?.() || 'not accessible',
sessionId: ph.get_session_id?.() || 'not accessible',
featureFlags: ph.getFeatureFlag ? Object.keys(ph.featureFlags?.flags || {}) : [],
activeFeatureFlags: ph.getFeatureFlag ?
Object.entries(ph.featureFlags?.flags || {})
.filter(([_, v]) => v)
.map(([k]) => k) : []
};
})()Step 2b: Check for Bundled PostHog (Remote Config)
If posthog is not on window, check for bundled implementations that use _POSTHOG_REMOTE_CONFIG:
(() => {
const remoteConfig = window._POSTHOG_REMOTE_CONFIG;
if (!remoteConfig) {
return { found: false };
}
const tokens = Object.keys(remoteConfig);
const configs = tokens.map(token => {
const cfg = remoteConfig[token]?.config || {};
return {
token,
hasFeatureFlags: cfg.hasFeatureFlags || false,
autocapture: !cfg.autocapture_opt_out,
sessionRecording: cfg.sessionRecording || false,
heatmaps: cfg.heatmaps || false,
surveys: cfg.surveys || false,
capturePerformance: cfg.capturePerformance || {},
defaultIdentifiedOnly: cfg.defaultIdentifiedOnly || false
};
});
return {
found: true,
bundled: true,
configs
};
})()Step 2c: Check Console for PostHog Debug Messages
With ?__posthog_debug=true, PostHog outputs detailed logs. Use list_console_messages and look for [PostHog.js] entries:
Key messages to look for:
[PostHog.js] Persistence loaded- Shows persistence type (localStorage, sessionStorage, cookie)[PostHog.js] [Surveys] Surveys loaded successfully- Surveys module loaded[PostHog.js] [Surveys] flags response received, isSurveysEnabled: X- Whether surveys are enabled[PostHog.js] [SessionRecording]- Session recording status[PostHog.js] [WebExperiments]- Web experiments/feature flags[PostHog.js] set_config- Configuration changes
Important distinction:
Module loaded = The JavaScript file loaded successfully
Feature enabled = The feature is turned on in PostHog settings
A module can load but still be disabled. For example:
[PostHog.js] [Surveys] Surveys loaded successfully <- Module loaded
[PostHog.js] [Surveys] flags response received, isSurveysEnabled: false <- Feature disabledStep 3: Check for PostHog Script
Look for PostHog scripts in the page:
(() => {
const scripts = Array.from(document.querySelectorAll('script'));
const posthogScripts = scripts.filter(s =>
(s.src && (s.src.includes('posthog') || s.src.includes('ph.js'))) ||
(s.textContent && (s.textContent.includes('posthog.init') || s.textContent.includes('!function(t,e)')))
);
return {
found: posthogScripts.length > 0,
scripts: posthogScripts.map(s => ({
src: s.src || 'inline',
async: s.async,
defer: s.defer,
type: s.type || 'text/javascript'
}))
};
})()Step 4: Check Network Requests
Filter network requests to find PostHog traffic. PostHog may use:
Standard domains:
*.posthog.comus.i.posthog.com/eu.i.posthog.comus-assets.i.posthog.com/eu-assets.i.posthog.com
Custom proxy domains (common patterns):
ph.yourcompany.comanalytics.yourcompany.comt.yourcompany.comAny domain with
/array/phc_in the path (PostHog config)
Endpoints to look for:
/e/or/capture/- Events/s/- Session recording/decide/or/flags/- Feature flags/batch/- Batched events/array/phc_*/config.js- Remote config (bundled implementations)/static/surveys.js- Surveys module/static/recorder.js- Session recording module
How to identify a custom proxy:
Look for requests with PostHog-specific paths (
/flags/,/array/phc_)Check network request details for PostHog headers
Look for
phc_tokens in request URLs or bodies
Step 5: Check for Common Issues
Run diagnostics:
(() => {
const issues = [];
// Check if posthog exists
if (typeof posthog === 'undefined') {
issues.push('PostHog not found on window object');
return { issues };
}
// Check for multiple instances
if (window.__POSTHOG_INSTANCES__ && window.__POSTHOG_INSTANCES__.length > 1) {
issues.push('Multiple PostHog instances detected - may cause duplicate events');
}
// Check if initialized
if (!posthog.get_distinct_id || !posthog.get_distinct_id()) {
issues.push('PostHog may not be fully initialized');
}
// Check consent mode
if (posthog.has_opted_out_capturing && posthog.has_opted_out_capturing()) {
issues.push('User has opted out of tracking');
}
// Check for debug mode in production
const isDebug = posthog.config?.debug || posthog.get_config?.('debug');
const hostname = window.location.hostname;
if (isDebug && !hostname.includes('localhost') && !hostname.includes('127.0.0.1')) {
issues.push('Debug mode is enabled in production');
}
// Check autocapture
const autocapture = posthog.config?.autocapture ?? posthog.get_config?.('autocapture');
if (autocapture === false) {
issues.push('Autocapture is disabled - only manual events will be tracked');
}
return {
issues: issues.length > 0 ? issues : ['No issues detected'],
checksRun: true
};
})()Step 6: Capture Recent Events (if debug available)
If debug mode is on or we can access the queue:
(() => {
if (typeof posthog === 'undefined') return { events: [] };
// Try to get queued events
const queue = posthog._requestQueue?.queue ||
posthog.requestQueue?.queue ||
[];
// Get recent events from persistence if available
const stored = posthog.persistence?.props?.$stored_events || [];
return {
queuedEvents: queue.length,
recentEventTypes: [...new Set([...queue, ...stored].map(e => e?.event || 'unknown').slice(0, 20))]
};
})()Step 7: Detect Other Analytics Tools
Scan network requests and scripts to identify all analytics/tracking tools on the page. Use known patterns for named tools, and detect unknown tracking scripts as a fallback.
(() => {
const scripts = Array.from(document.querySelectorAll('script[src]')).map(s => s.src);
const hostname = window.location.hostname.replace('www.', '');
const knownTools = [];
const matchedScripts = new Set();
const patterns = {
'Google Analytics': /google-analytics\.com|gtag\/js/i,
'Google Tag Manager': /googletagmanager\.com\/gtm/i,
'Facebook Pixel': /connect\.facebook\.net.*fbevents/i,
'LinkedIn Insight': /snap\.licdn\.com/i,
'HubSpot': /js\.hs-scripts\.com|js\.hsforms\.com/i,
'Hotjar': /static\.hotjar\.com/i,
'Segment': /cdn\.segment\.com/i,
'Mixpanel': /cdn\.mxpnl\.com|mixpanel\.com/i,
'Amplitude': /cdn\.amplitude\.com/i,
'Heap': /heap-analytics\.com|heapanalytics\.com/i,
'Intercom': /widget\.intercom\.io|intercomcdn\.com/i,
'Drift': /js\.driftt\.com/i,
'Zendesk': /static\.zdassets\.com/i,
'Crisp': /client\.crisp\.chat/i,
'FullStory': /fullstory\.com\/s\/fs\.js/i,
'LogRocket': /cdn\.logrocket\.com/i,
'Sentry': /browser\.sentry-cdn\.com/i,
'Datadog': /datadoghq\.com/i,
'Snowplow': /cdn\.snowplow/i,
'Rudderstack': /cdn\.rudderlabs\.com/i,
'Clearbit': /tag\.clearbitscripts\.com/i,
'Dreamdata': /cdn\.dreamdata\.cloud/i,
'GrowthBook': /cdn\.growthbook\.io/i,
'LaunchDarkly': /sdk\.launchdarkly\.com/i,
'Optimizely': /cdn\.optimizely\.com/i,
'VWO': /dev\.visualwebsiteoptimizer\.com/i,
'Ahrefs': /analytics\.ahrefs\.com/i,
'AdRoll': /s\.adroll\.com/i,
'Factors.ai': /app\.factors\.ai/i,
'Vector': /cdn\.vector\.co/i,
'Leadfeeder': /sc\.lfeeder\.com/i,
'Pendo': /cdn\.pendo\.io/i,
'Chameleon': /fast\.chameleon\.io/i,
'Appcues': /fast\.appcues\.com/i,
'UserPilot': /js\.userpilot\.io/i,
'Mouseflow': /cdn\.mouseflow\.com/i,
'Lucky Orange': /tools\.luckyorange\.com/i,
'Crazy Egg': /script\.crazyegg\.com/i,
'Plausible': /plausible\.io\/js/i,
'Fathom': /cdn\.usefathom\.com/i,
'Simple Analytics': /scripts\.simpleanalyticscdn\.com/i,
'Matomo': /matomo\.js|piwik\.js/i,
'Klaviyo': /static\.klaviyo\.com/i,
'Customer.io': /track\.customer\.io/i,
'Braze': /sdk\.iad-\d+\.braze\.com/i,
'OneSignal': /cdn\.onesignal\.com/i,
'Insider': /insr\.io/i,
'Mutiny': /cdn\.mutinycdn\.com/i,
'Qualified': /js\.qualified\.com/i,
'Chilipiper': /js\.chilipiper\.com/i,
'Typekit': /use\.typekit\.net/i,
'Google Fonts': /fonts\.googleapis\.com/i,
'Cookiebot': /consent\.cookiebot\.com/i,
'OneTrust': /cdn\.cookielaw\.org/i,
'TrustArc': /consent\.trustarc\.com/i,
'Osano': /cmp\.osano\.com/i,
'Usercentrics': /app\.usercentrics\.eu/i,
'OpenLI/Legal Monster': /widgets\.legalmonster\.com|openli\.com/i,
'Nelio A/B Testing': /nelio-ab-testing/i,
'Mesh': /mesh-interactive|withmesh\.com/i,
'Reddit Pixel': /redditstatic\.com|rdt\.li/i,
'Webflow': /wdfl\.co|webflow\.com\/js/i,
'Dub.co': /dubcdn\.com|dub\.co/i
};
// Match known tools
for (const [name, pattern] of Object.entries(patterns)) {
for (const src of scripts) {
if (pattern.test(src)) {
knownTools.push(name);
matchedScripts.add(src);
break;
}
}
}
// Find unknown tracking scripts
const trackingKeywords = /track|analytics|pixel|tag|beacon|collect|measure|metric|event|telemetry|monitor/i;
const unknownScripts = scripts.filter(src => {
if (matchedScripts.has(src)) return false;
try {
const url = new URL(src);
const scriptHost = url.hostname.replace('www.', '');
// Skip same-domain scripts
if (scriptHost === hostname || scriptHost.endsWith('.' + hostname)) return false;
// Skip common CDNs that host non-tracking code
if (/unpkg\.com|jsdelivr\.net|cdnjs\.cloudflare\.com|ajax\.googleapis\.com/i.test(scriptHost)) return false;
// Include if it has tracking-like keywords or is from a third-party
return trackingKeywords.test(src) || true;
} catch {
return false;
}
});
// Extract just the domain from unknown scripts for cleaner output
const unknownDomains = [...new Set(unknownScripts.map(src => {
try {
return new URL(src).hostname;
} catch {
return src;
}
}))].sort();
return {
knownTools: [...new Set(knownTools)].sort(),
unknownScripts: unknownDomains
};
})()Response Format
After inspection, provide a structured summary. Be factual and concise - no commentary or recommendations unless asked. Use emojis to indicate status at a glance.
Status emojis:
✅ = Yes / Enabled / Active / Installed
❌ = No / Disabled / Not found
⚠️ = Warning / Issue detected
## PostHog Implementation Summary
### Status
✅ Installed / ✅ Installed (bundled) / ❌ Not Found
### Implementation Type
[Global window.posthog / Bundled (not exposed globally) / Custom proxy]
### Configuration
- **Version:** [version]
- **API Host:** [host] ([US/EU Cloud] / [Custom proxy] / [Self-hosted])
- **Project Token:** [full token]
- **Persistence:** [localStorage/sessionStorage/cookie/memory]
### Features (Module Loaded → Feature Enabled)
| Feature | Module Loaded | Enabled |
|---------|---------------|---------|
| Autocapture | ✅ / ❌ | ✅ / ❌ |
| Session Recording | ✅ / ❌ | ✅ / ❌ |
| Surveys | ✅ / ❌ | ✅ / ❌ |
| Heatmaps | ✅ / ❌ | ✅ / ❌ |
| Feature Flags | ✅ / ❌ | ✅ / ❌ |
| Web Vitals | ✅ / ❌ | ✅ / ❌ |
### Identifiers
- **Distinct ID:** [id]
- **Session ID:** [id]
### Feature Flags
[List of active flags or "None loaded"]
### Network Activity
- Events endpoint: ✅ / ❌
- Session recording: ✅ / ❌
- Decide/flags endpoint: ✅ / ❌
- Surveys endpoint: ✅ / ❌
### Issues Found
✅ None detected
— or —
⚠️ [Issue description]
### Script Loading
- **Source:** [CDN/Self-hosted/NPM bundle/Custom proxy]
- **Loading:** [Async/Sync/Defer]
### Other Analytics Tools Detected
[List of recognized analytics, tracking, and marketing tools]
### Other External Scripts
[Third-party script domains not matched to known tools]Common Questions and How to Answer Them
"How is PostHog implemented on this page?"
Run full inspection workflow and provide complete summary.
"Is PostHog tracking working?"
Check if posthog object exists
Verify network requests are being sent
Check for any errors in console
Look for opted-out status
"What events are being tracked?"
Check autocapture status
Look at network requests to
/e/or/capture/Try to access event queue
Note if $pageview, $pageleave, etc. are enabled
"Is session recording enabled?"
Check config for recording settings
Look for
/s/network requestsCheck sessionRecording object state
"What feature flags are active?"
Check featureFlags object on posthog
Look for
/decide/network requestList all flags and their values
"Are there any issues with the implementation?"
Run the diagnostic checks and report findings.
"Is this using the EU or US cloud?"
Check the api_host configuration:
us.i.posthog.com= US Cloudeu.i.posthog.com= EU Cloudapp.posthog.com= Legacy (defaults to US)Custom domain = Self-hosted or proxy
Example Conversation
User: "How is PostHog implemented on https://example.com?"
Claude: "I'll navigate to example.com with debug mode enabled and inspect the PostHog implementation."
[Navigates to https://example.com?__posthog_debug=true] [Runs JavaScript checks] [Checks console for PostHog debug messages] [Analyzes network requests]
Claude:
## PostHog Implementation Summary
### Status
✅ Installed
### Implementation Type
Global window.posthog
### Configuration
- **Version:** 1.96.1
- **API Host:** https://us.i.posthog.com (US Cloud)
- **Project Token:** phc_abc123def456ghi789jkl012mno345
- **Persistence:** localStorage+cookie
### Features (Module Loaded → Feature Enabled)
| Feature | Module Loaded | Enabled |
|---------|---------------|---------|
| Autocapture | ✅ | ✅ |
| Session Recording | ✅ | ✅ |
| Surveys | ✅ | ❌ |
| Heatmaps | ❌ | ❌ |
| Feature Flags | ✅ | ✅ |
| Web Vitals | ✅ | ✅ |
### Identifiers
- **Distinct ID:** 018d4f2a-1234-7abc-def0-123456789abc
- **Session ID:** 018d4f2a-5678-7xyz-abc0-987654321xyz
### Feature Flags
- `new-checkout-flow` ✅
- `beta-features` ❌
### Network Activity
- Events endpoint: ✅
- Session recording: ✅
- Decide/flags endpoint: ✅
- Surveys endpoint: ✅
### Issues Found
✅ None detected
### Script Loading
- **Source:** CDN (us-assets.i.posthog.com)
- **Loading:** Async
### Other Analytics Tools Detected
- Google Tag Manager
- Google Analytics
- HubSpot
### Other External Scripts
- cdn.example-vendor.comExample 2: Authenticated page with custom proxy
User: "Check PostHog on https://app.example.com/dashboard"
Claude: "I'll navigate to that page with debug mode enabled."
[Navigates to https://app.example.com/dashboard?__posthog_debug=true] [Takes snapshot, sees login page]
Claude: "I've opened the page but it requires login. Please log in using the Chrome browser I just opened. Let me know when you're on the dashboard."
User: "I'm logged in"
Claude: [Takes new snapshot, verifies authenticated, runs inspection]
## PostHog Implementation Summary
### Status
✅ Installed (bundled)
### Implementation Type
Bundled (not exposed globally) via custom proxy
### Configuration
- **Version:** 1.257.2
- **API Host:** ph.example.com (Custom proxy)
- **Project Token:** phc_abc123def456ghi789jkl012mno345
- **Persistence:** sessionStorage
### Features (Module Loaded → Feature Enabled)
| Feature | Module Loaded | Enabled |
|---------|---------------|---------|
| Autocapture | ✅ | ❌ |
| Session Recording | ❌ | ❌ |
| Surveys | ✅ | ❌ |
| Heatmaps | ❌ | ❌ |
| Feature Flags | ✅ | ✅ |
| Web Vitals | ✅ | ❌ |
### Identifiers
- **Distinct ID:** (not accessible - bundled)
- **Session ID:** (not accessible - bundled)
### Network Activity
- Events endpoint: ✅
- Session recording: ❌
- Decide/flags endpoint: ✅
- Surveys endpoint: ✅ (module loaded, feature disabled)
### Issues Found
✅ None detected
### Script Loading
- **Source:** Custom proxy (ph.example.com)
- **Loading:** Bundled in appFiles
- .claude-plugin/plugin.json227 B
- ATTRIBUTION.mdAdded by AutoGineer865 B
- LICENSELicence file added by AutoGineer1.0 KiB
- README.md5.7 KiB
- SKILL.md21.4 KiB
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
Security
No issues found by our static scan· No issues found
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
- Published by
- PostHog
- Publisher
- PostHog (Official)
- Source
- PostHog/skills · skills/team/customer-success/posthog-debugger · 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 posthog-debugger.zip