Lenny Skills is a collection of product-management and engineering workflows for Claude Code and other AI agents, covering areas such as strategy, research, planning, shipping, growth, and hiring. Each skill gives an agent specialized guidance, frameworks, checklists, or templates for product work, and the catalogue contains many of these skills.
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 skills add RefoundAI/lenny-skills --skill product-experimentsgit clone --depth 1 https://github.com/RefoundAI/lenny-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/refoundai/lenny-skills/product-experiments)<a href="https://agentmods.dev/skills/refoundai/lenny-skills/product-experiments"><img src="https://agentmods.dev/badge/skills/refoundai/lenny-skills/product-experiments/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/refoundai/lenny-skills/product-experiments"><img src="https://agentmods.dev/badge/skills/refoundai/lenny-skills/product-experiments.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00029 | $0.01594 |
| Opus 5 | $0.00015 | $0.00797 |
| Sonnet 5 | $0.00006 | $0.00319 |
| Haiku 4.5 | $0.00003 | $0.00159 |
Grade A, and why
product-experiments 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Product Experimentation Excellence
Drive measurable growth and mitigate risk through rigorous A/B testing and data-driven learning.
Help the user with product experimentation excellence using insights from 9 guests and posts across Lenny's Podcast and Newsletter.
How to Help
- Hypothesis Definition - Guide the user in drafting clear, falsifiable hypotheses based on user behavior theories.
- Experimental Design - Help determine the right metrics, sample sizes, and guardrail metrics for a clean test.
- Statistical Analysis - Support the interpretation of p-values, confidence intervals, and potential sample ratio mismatches.
- Strategic Evaluation - Assist in deciding whether to ship, iterate, or kill a feature based on experiment results and long-term business impact.
Core Principles
Use long-term holdouts for true incrementality
Archie Abrams: "So we constantly will relook at an experiment a year later, see that the way the GMV curve for the distribution was different than we might've originally thought. And that'll actually change what we do from that previous experiment. And so there's a lot of longterm monitoring of experiments over these very long time horizons to both inform what those input metrics are and more importantly hold ourselves accountable to, did we actually move what we cared about, which is that longterm GMV, in the right way?"
Implement holdout groups for one or more years to distinguish between immediate growth and short-term pull-forward effects. This ensures you are measuring the genuine downstream business impact of changes.
Focus experiments on risk mitigation
Lauryn Isford: "So, with all that said, generally my advice is to experiment when you need to and to primarily see it as a risk mitigation tactic when you're making dramatic changes and to let the product development process do more work. So, spend more time with customers, be more rigorous in understanding precisely what problem you're solving, get mocks in front of people and see how they react, and hopefully have more conviction than you otherwise would when you ship something that it's okay if every customer sees it tomorrow and that the experiment doesn't actually matter as much."
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago First seen · 90 lines · 29 tokens per session scan A 1b80dec260cc
product-experiments is a skill published in the GitHub repository RefoundAI/lenny-skills (1,315 stars, last pushed 1mo ago), licensed MIT. It adds 29 tokens to every session and 1,594 once invoked, about $0.0001 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 skills, from other repositories
llama-cpp
Run LLM inference with llama.cpp on CPU, Apple Silicon, AMD/Intel GPUs, or NVIDIA — plus GGUF model conversion and quantization (2–8 bit with K-quants and imatrix). Covers CLI, Python bindings, OpenAI-compatible server, and Ollama/LM Studio integration. Use for edge deployment, M1/M2/M3/M4 Macs, CUDA-less…
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior. 4-phase root cause investigation — NO fixes without understanding the problem first.
github-auth
Set up GitHub authentication for the agent using git (universally available) or the gh CLI. Covers HTTPS tokens, SSH keys, credential helpers, and gh auth — with a detection flow to pick the right method automatically.
ideation
Generate project ideas through creative constraints. Use when the user says 'I want to build something', 'give me a project idea', 'I'm bored', 'what should I make', 'inspire me', or any variant of 'I have tools but no direction'. Works for code, art, hardware, writing, tools, and anything that can be made.
notion
Notion API for creating and managing pages, databases, and blocks via curl. Search, create, update, and query Notion workspaces directly from the terminal.
ocr-and-documents
Extract text from PDFs and scanned documents. Use webextract for remote URLs, pymupdf for local text-based PDFs, marker-pdf for OCR/scanned docs. For DOCX use python-docx, for PPTX see the powerpoint skill.