Set Up PostHog MCP Server

Prerequisites

• PostHog account with a project API key and personal API key
• Claude Code installed with MCP support

Steps

1. Generate API keys. Via the PostHog API or dashboard, create a personal API key with read access to all resources. Note the Project API Key from project settings. You need both: the personal key for querying and the project key for event ingestion.

2. Install the MCP server. Add the PostHog MCP server to your Claude Code MCP config file (.claude/settings.json or project-level .mcp.json):

{
  "posthog": {
    "command": "npx",
    "args": ["-y", "@anthropic/posthog-mcp"],
    "env": {
      "POSTHOG_API_KEY": "<personal-api-key>",
      "POSTHOG_PROJECT_ID": "<project-id>",
      "POSTHOG_HOST": "https://app.posthog.com"
    }
  }
}

For self-hosted PostHog, set POSTHOG_HOST to your instance URL.

1. Verify the connection. After restarting Claude Code, use the MCP to query recent events. Expected successful output: a list of event objects with event, timestamp, and properties fields. Authentication errors indicate an incorrect personal API key or project ID.

2. Available MCP operations. The PostHog MCP server supports:

   • query_events -- fetch events with filters
   • run_hogql_query -- execute HogQL (PostHog SQL dialect) queries
   • list_feature_flags -- read flag configurations
   • get_experiment_results -- read A/B test outcomes
   • get_insight -- fetch saved insight data
   • query_persons -- look up user records and cohort membership

3. Test HogQL access. Run a test query through the MCP:

SELECT count() FROM events WHERE event = 'signup_completed' AND timestamp > now() - interval 7 day

Verify the query executes and returns a numeric result. HogQL is the primary interface for ad-hoc PostHog analysis.

1. Security. Store API keys in environment variables or a .env file listed in .gitignore. Never commit keys to version control. Rotate keys immediately if exposed.