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.
npx agentmods add instructions/posthog/mcp/claude-mdgit clone --depth 1 https://github.com/PostHog/mcpWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.01247 | $0.01247 |
| Opus 5 | $0.00624 | $0.00624 |
| Sonnet 5 | $0.00249 | $0.00249 |
| Haiku 4.5 | $0.00125 | $0.00125 |
Grade A, and why
mcp CLAUDE.md 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- posthog-mcp CLAUDE.md — 94% identical, 2 lines differ
How it starts
The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Development Commands
pnpm run dev- Start development server using Wranglerpnpm run deploy- Deploy to Cloudflare Workerspnpm run format- Format code using Biomepnpm run lint:fix- Lint and fix code using Biomepnpm run schema:build:json- Generate JSON schema from Zod schemas for Python/other language implementationswrangler types- Generate TypeScript types for Cloudflare Workers
Code Architecture
This is a PostHog MCP (Model Context Protocol) server built on Cloudflare Workers that provides API access to PostHog analytics data. The server acts as a bridge between MCP clients (like Claude Desktop, Cursor, Windsurf) and PostHog's API.
Project Structure
The repository is organized to support multiple language implementations:
mcp/
├── typescript/ # TypeScript implementation
│ ├── src/ # TypeScript source code
│ ├── tests/ # TypeScript tests
│ └── scripts/ # TypeScript build scripts
├── python/ # Python implementation (planned)
├── schema/ # Shared schema files for all implementations
│ └── tool-inputs.json # Generated JSON schema for cross-language compatibility
├── biome.json # Shared code formatting configuration
└── CLAUDE.md # Project documentation
Key Components (TypeScript Implementation)
- Main MCP Class (
typescript/src/integrations/mcp/index.ts):MyMCPextendsMcpAgentand defines all available tools for interacting with PostHog - Unified API Client (
typescript/src/api/client.ts):ApiClientclass provides type-safe methods for all PostHog API interactions with proper error handling and schema validation - Schema Validation (
typescript/src/schema/): Zod schemas for validating API requests and responses - Tool Input Schemas (
typescript/src/schema/tool-inputs.ts): Centralized Zod schemas for all MCP tool inputs, exported toschema/tool-inputs.jsonfor other language implementations - Caching (
typescript/src/lib/utils/cache/): User-scoped memory cache for storing project/org state - Documentation Search (
typescript/src/inkeepApi.ts): Integration with Inkeep for PostHog docs search - Utility Functions (
typescript/src/lib/utils/api.ts): Helper functions for pagination and URL generation
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.
- 2d ago First seen · 102 lines · 1,247 tokens per session scan A 8838a923e29d
mcp CLAUDE.md is an instructions file published in the GitHub repository PostHog/mcp (151 stars, last pushed 7mo ago), licensed MIT. It adds 1,247 tokens to every session, about $0.0062 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.
Other instructions, from other repositories
ollama AGENTS.md
AGENTS.md instructions for ollama/ollama, covering agents.md and building.
fastmcp CLAUDE.md
Claude Code instructions for PrefectHQ/fastmcp, covering fastmcp development guidelines, required development workflow, repository structure, core mcp objects and development rules.
ollama CLAUDE.md
Claude Code instructions for ollama/ollama: See AGENTS.md for the shared agent instructions for this repository.
llm AGENTS.md
Instructions for simonw/llm, covering agents.md, setting up a development environment and building the documentation.
plano CLAUDE.md
Instructions for katanemo/plano, covering claude.md, build & test commands, rust — wasm plugins (must target wasm32-wasip1), rust — brightstaff binary (native target) and rust — tests, format, lint.
oumi AGENTS.md
AGENTS.md instructions for oumi-ai/oumi, covering agent instructions, publication policy and working with contributions.