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simulate-new-user

Testing & Quality
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Send synthetic first-time-visitor traffic to a URL and confirm that PostHog $pageview events fire. Use when a customer wants to verify that anonymous visitor tracking works, after deploying instrumentation changes, or when debugging "events not arriving" reports.

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How to use this skill

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Source SKILL.md: https://github.com/PostHog/posthog/blob/HEAD/tools/traffic-sim/skills/simulate-new-user/SKILL.md

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Simulate new-user traffic

Drives a fresh browser context for each visit (no cookies, no localStorage), goes to the given URL, scrolls a bit, and reports which PostHog events fired. Each visit looks to PostHog like a brand-new anonymous visitor.

When to use

  • Confirm $pageview fires on the first visit (no cookies present).
  • Confirm an anonymous distinct_id is generated and a PostHog request is sent within a few seconds of page load.
  • Reproduce "events not showing up for new users" reports.

How to invoke

Call the simulate_new_user MCP tool with:

  • url (required) — the page to visit, e.g. https://example.com/pricing.
  • visits (default 3) — number of fresh-context visits.
  • interval (default 5.0) — seconds between visits.
  • posthog_host (default https://us.i.posthog.com) — set to https://eu.i.posthog.com for the EU cloud, or your self-hosted host (e.g. https://ph.example.com).

Each visit takes ~10s of Playwright time plus the interval, so plan accordingly.

Interpreting the result

The tool returns a structured summary:

{
  "run_id": "a1b2c3d4",
  "scenario": "new-user",
  "total_visits": 3,
  "posthog_requests": 6,
  "posthog_requests_ok": 6,
  "events_by_type": { "$pageview": 3, "$autocapture": 3 },
  "pageviews": 3,
  "errors": [],
  "verified": true,
}
  • verified: true means at least one $pageview was captured per visit and no errors occurred — the new-user flow works.
  • verified: false with pageviews: 0 means PostHog isn't firing pageviews. Run check_posthog_loading next to see whether the snippet is even loaded.
  • posthog_requests_ok < posthog_requests means PostHog returned non-2xx responses. Check the project's ingestion limits and api_host configuration.