posthog-integration

A set of development rules for projects that use PostHog, an analytics and feature-flag service.

In plain words
What is it for?
Use it when adding PostHog feature flags, analytics events, custom properties, or TypeScript and JavaScript constants for their names.
Why use it?
It reduces mistakes such as exposing missing API keys, scattering feature-flag checks, or using inconsistent event and property names.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/posthog/wizard/posthog-integration
Clone the repo
git clone --depth 1 https://github.com/PostHog/wizard

Made for: Cursor.

Per session 316 This file is loaded in full into every session.
When invoked 316 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00316 $0.00316
Opus 5 $0.00158 $0.00158
Sonnet 5 $0.00063 $0.00063
Haiku 4.5 $0.00032 $0.00032

Measured 2d ago against content hash 9c0eba90b265, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

posthog-integration scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

e2e-tests/test-applications/react-native-test-app/.cursor/rules/posthog-integration.mdc · 28 lines

What it actually says

Never hallucinate an API key. Instead, always use the API key populated in the .env file.

Feature flags

A given feature flag should be used in as few places as possible. Do not increase the risk of undefined behavior by scattering the same feature flag across multiple areas of code. If the same feature flag needs to be introduced at multiple callsites, flag this for the developer to inspect carefully.

If a job requires creating new feature flag names, make them as clear and descriptive as possible.

If using TypeScript, use an enum to store flag names. If using JavaScript, store flag names as strings to an object declared as a constant, to simulate an enum. Use a consistent naming convention for this storage. enum/const object members should be written UPPERCASE_WITH_UNDERSCORE.

Gate flag-dependent code on a check that verifies the flag's values are valid and expected.

Custom properties

If a custom property for a person or event is at any point referenced in two or more files or two or more callsites in the same file, use an enum or const object, as above in feature flags.

Naming

Before creating any new event or property names, consult with the developer for any existing naming convention. Consistency in naming is essential, and additional context may exist outside this project. Similarly, be careful about any changes to existing event and property names, as this may break reporting and distort data for the project.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 28 lines · 316 tokens per session scan A 9c0eba90b265

Subscribe to this mod's changes

posthog-integration is a cursor rule published in the GitHub repository PostHog/wizard (190 stars, last pushed 2d ago), licensed MIT. It adds 316 tokens to every session, about $0.0016 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.