design-it-twice SKILL.md skillA
design-it-twice from etr/groundwork is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add etr/groundwork/design-it-twice@git:20260622.3609064Pins git:20260622.3609064 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- etr/groundwork
- Path
skills/design-it-twice/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260622.3609064, committed Jun 22, 2026
- Size
- 4,340 bytes
- Repository stars
- 44
- License
- MIT
Use before committing to a non-trivial module, service boundary, or public API - generate 2-3 divergent interface designs, compare them on depth/locality/seam, and recommend one.
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
# Design It Twice ## Overview Your first interface is rarely your best (**Design it twice**, Ousterhout). Before you commit a module boundary, generate genuinely different designs and compare them — the cost of exploring on paper is trivial next to the cost of a shallow interface that **Hyrum's Law** then freezes into a contract. **Core principle:** Aim for **deep modules** — a simple interface hiding substantial functionality. A design that merely forwards calls is shallow and usually a liability. This is a build-time and architecture-time discipline. [[design-architecture]] and [[swarm-design-architecture]] invoke it for module boundaries; invoke it directly any time you're about to design a single non-trivial interface. ## When to Use - A new module, service boundary, or public API - A refactor that reshapes an existing interface many callers depend on - Any seam where a future change is likely to land and you want it to land in one place Skip for trivial or single-call-site code, or interfaces fully dictated by an existing contract. ## Process ### 1. Frame the problem space …
Read the whole file at its exact version.
How to install
mdr add etr/groundwork/design-it-twice@sha256:fbac7454b4ce5be0The line at the top of this page pins the label git:20260622.3609064, 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_ac4kjodydqyzmemy)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Jun 22, 2026.
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 (4340 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
etr/groundwork · 44 stars · license MIT · pushed 2026-10-30 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_ac4kjodydqyzmemy GET https://markdownregistry.com/api/v1/resolve?ref=etr/groundwork/design-it-twice GET https://markdownregistry.com/api/v1/blob/fbac7454b4ce5be0337cf7e098686bf994dbb40da84f738819e8dcd3c3d56f5e
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.