Ivx MCP Posthog

PostHog — product analytics

What it is

PostHog's official hosted MCP over the org's US-cloud PostHog instance: insights, dashboards, HogQL, session replays, feature flags, and error tracking.

• Tile id: posthog (group "Measure & monitor")
• MCP endpoint: https://mcp.posthog.com/mcp (externally reachable — direct attach works)
• Auth: Authorization: Bearer <personal API key> (phx_..., PostHog Settings → Personal API keys). A platform default is seeded at the gateway (POSTHOG_MCP_TOKEN, secret posthog-mcp-secret), so admin_call_mcp { tileId: "posthog" } needs no key.

Key tools

Tool names are PostHog's own and evolve — discover them:

admin_call_mcp { tileId: "posthog", method: "tools/list" }

Expect insight/dashboard CRUD, a HogQL query runner, feature-flag management, and error-tracking queries. The gateway treats list/get/retrieve/search/query/read-style tools as read-only; anything else (creating insights, toggling flags) counts as a write.

Worked example — "what's the signup funnel conversion this week, and did the new flag change it?"

1. tools/list → find the query/insight tools.
2. Run the funnel: either an existing insight (search insights for "signup funnel") or a HogQL query over the signup events for this week vs last.
3. Look up the feature flag by key → note its rollout % and variants.
4. Segment the funnel by flag variant (HogQL properties.$feature/<key>).
5. Report: conversion per step, week-over-week delta, per-variant split. If asked to change the flag rollout — that's a write to production behavior: confirm first.

Common failure modes

• 401 Unauthorized — bad/expired phx_ key, or the gateway default token isn't seeded yet (posthog-mcp-secret). Report it; don't ask the user to paste a key into chat.
• 403 / missing scope — personal API keys are scoped; a key without insight:read or feature_flag:write fails only on those tools. The error names the missing scope — regenerate the key with it.
• Wrong project — org has multiple PostHog projects; if numbers look off by 10x, check which project id the tool call targeted.
• HogQL errors — property names are case-sensitive and event names exact; list events/properties first instead of guessing.

Cautions

Feature flags gate live product behavior — never create/modify/delete a flag without explicit approval. Session replays contain user PII: quote aggregates, don't dump replay contents into chat. Never paste phx_ keys into chat.