ab-testing SKILL.md skillA
ab-testing from ericrisco/rsc-harness is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add ericrisco/rsc-harness/ab-testing@git:20260729.3ecb845Pins git:20260729.3ecb845 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- ericrisco/rsc-harness
- Path
skills/ab-testing/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260729.3ecb845, committed Jul 29, 2026
- First version recorded
- Jun 2, 2026
- Size
- 9,831 bytes
- Repository stars
- 236
- License
- MIT
Use when designing or analyzing a controlled experiment — falsifiable hypothesis, sample size from an MDE, reading significance/CI/power, CUPED, or rescuing tests that won't go significant. NOT recurring metric tracking (that is `analytics`), NOT north-star/KPI trees (that is `kpi-framework`), NOT projecting metrics forward (that is `forecasting`).
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# A/B testing — design and read a defensible experiment An experiment without a pre-committed sample size and a single primary metric is not an experiment. It is a dashboard you stare at until it tells you what you wanted to hear. The discipline lives almost entirely *before* traffic ships: a falsifiable hypothesis, one primary metric, a sample size derived from the smallest effect worth detecting, and a stop rule you cannot renegotiate at 2pm on day four. ## Pre-test checklist — every line true before any traffic Each one is a place experiments die silently. - [ ] A **falsifiable hypothesis** — names the change, the direction, and the metric it moves. - [ ] Exactly **ONE primary metric**. More than one primary = multiple comparisons = inflated false positives. - [ ] **Guardrail metrics** — what you refuse to harm (latency, refunds, unsubscribes) even for a win. - [ ] The **randomization unit = the analysis unit** (usually the user). Mixing them is pseudoreplication. - [ ] An **MDE** — the smallest lift that would change a decision. Not "any difference." - [ ] A **computed sample size** and the **duration** it implies at your real daily eligible traffic. …
Read the whole file at its exact version.
How to install
mdr add ericrisco/rsc-harness/ab-testing@sha256:9e283bf5c9508803The line at the top of this page pins the label git:20260729.3ecb845, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_ugxqwri7f3t3oiyc)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Jun 2, 2026 and Jul 29, 2026, about one every 57 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260729.3ecb845 latest | 2026-07-29 | 3ecb845 | 9,831 B | A | view · diff |
| git:20260602.bd03869 | 2026-06-02 | bd03869 | 12,012 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9831 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
ericrisco/rsc-harness · 236 stars · license MIT · pushed 2026-10-21 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_ugxqwri7f3t3oiyc GET https://markdownregistry.com/api/v1/resolve?ref=ericrisco/rsc-harness/ab-testing GET https://markdownregistry.com/api/v1/blob/9e283bf5c9508803825cd116a2a15e4999e82396fab4eb73190cd85614dacaf9
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
More from ericrisco/rsc-harness
Every file in ericrisco/rsc-harness