PostHog Context Capture

CLI and MCP server to look up PostHog persons and their events for debugging.

Installation

``bash
npm install -g posthog-context-capture
`

Setup

Set environment variables:

`bash
export POSTHOG_PERSONAL_API_KEY=phx_...
export POSTHOG_PROJECT_ID=12345
export POSTHOG_REGION=us # or "eu"
`

$3

Personal API Key:
1. Go to Settings → Personal API keys in PostHog
2. Click "+ Create a personal API Key"
3. Select the query:read scope
4. Copy the key (starts with phx_)

Project ID: Found in your PostHog URL: https://us.posthog.com/project/12345/...

CLI Usage

`bash


Look up person by email

posthog-lookup --email user@example.com

With recent events (defaults to last 30 days)

posthog-lookup --email user@example.com --events 100

Filter by timeframe

posthog-lookup --email user@example.com --from 7d
posthog-lookup --email user@example.com --from 2024-01-01 --to 2024-01-31

Filter by event type

posthog-lookup --email user@example.com --event-type pageview

Find persons by event

posthog-lookup --event checkout_failed --limit 10
posthog-lookup --event subscription_cancelled --from 7d --show-properties
`

MCP Server

The MCP server exposes PostHog lookup tools to AI assistants.

$3

Global (all projects) — add to ~/.mcp.json:

`json
{
"mcpServers": {
"posthog": {
"type": "stdio",
"command": "posthog-mcp",
"env": {
"POSTHOG_PERSONAL_API_KEY": "phx_...",
"POSTHOG_PROJECT_ID": "12345",
"POSTHOG_REGION": "us"
}
}
}
}
`

Per-project — add .mcp.json to your project root with the same config.

Restart Claude Code after adding. You'll be prompted to approve the server on first use.

$3

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

`json
{
"mcpServers": {
"posthog": {
"command": "posthog-mcp",
"env": {
"POSTHOG_PERSONAL_API_KEY": "phx_...",
"POSTHOG_PROJECT_ID": "12345",
"POSTHOG_REGION": "us"
}
}
}
}
`

$3

Add to Cursor settings (Cursor Settings → MCP), or create .cursor/mcp.json in your project:

`json
{
"mcpServers": {
"posthog": {
"command": "posthog-mcp",
"env": {
"POSTHOG_PERSONAL_API_KEY": "phx_...",
"POSTHOG_PROJECT_ID": "12345",
"POSTHOG_REGION": "us"
}
}
}
}
`

$3

- lookup_person_by_email - Find a person by email with their recent events
- lookup_persons_by_event - Find persons who triggered a specific event
- get_person_events` - Get events for a specific person ID

License

MIT