tdd SKILL.md skillA

tdd from marcellocurto/skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add marcellocurto/skills/tdd@git:20261029.444423a

Pins git:20261029.444423a in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: marcellocurto/skills
Path: skills/tdd/SKILL.md
Versions recorded: 12
Latest version: git:20261029.444423a, committed Oct 29, 2026
First version recorded: Aug 20, 2026
Size: 6,175 bytes
Repository stars: 3
License: none declared

Build features and bug fixes test-first, with tests that protect behavior. Use when about to implement a feature or bug fix that adds or changes behavior users or callers rely on, including requests that do not mention tests or TDD. Not for removing features or code, behavior-preserving refactors, design or UX exploration, prototypes, styling, copy, configuration, or data cleanup.

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

# Test-Driven Development

Work in small red → green → refactor cycles: write one behavior as a test, watch it fail, implement it, then tidy the changed code. Read the project's glossary and relevant ADRs if they exist, whatever their filenames, so tests use the project's domain terms.

## Decide whether a test is warranted

Write a test only when the change adds or alters a rule that users or callers will rely on from now on. Tests exist to catch realistic regressions of such rules; coverage by itself is not a reason to write one. If the change does not create such a rule, say so in one line and implement without the cycle.

Tests describe what the system does. Do not write a test that asserts a feature, route, option, or default is absent. A promised rejection or default is a behavior, so test the outcome itself: the endpoint returns 401 without credentials, or the destructive flag starts off. When removing behavior, delete the tests that covered it, find the callers that remain, and run the remaining suite; it covers only what it already tested, so check the remaining callers directly.
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add marcellocurto/skills/tdd@sha256:4662956a81c6bdfa

The line at the top of this page pins the label git:20261029.444423a, 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.

Badge

[![mdr](https://markdownregistry.com/badge/art_6mn5hdipoyitcenj.svg)](https://markdownregistry.com/a/art_6mn5hdipoyitcenj)

3 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 12 versions of this file, between Aug 20, 2026 and Oct 29, 2026, about one every 6 days.

version	committed	commit	size	audit
git:20261029.444423a latest	2026-10-29	444423a	6,175 B	A	view · diff
git:20261002.427fecc	2026-10-02	427fecc	6,096 B	A	view · diff
git:20261002.a2929d4	2026-10-02	a2929d4	6,043 B	A	view · diff
git:20261002.450a70e	2026-10-02	450a70e	5,639 B	A	view · diff
git:20261002.3cd9675	2026-10-02	3cd9675	5,747 B	A	view · diff
git:20260930.664568a	2026-09-30	664568a	4,765 B	A	view · diff
git:20260928.0bbe6db	2026-09-28	0bbe6db	10,152 B	A	view · diff
git:20260910.e524acd	2026-09-10	e524acd	10,014 B	A	view · diff
git:20260908.e500868	2026-09-08	e500868	7,389 B	A	view · diff
git:20260906.ccd7ead	2026-09-06	ccd7ead	7,713 B	A	view · diff
git:20260824.0c46ba8	2026-08-24	0c46ba8	6,473 B	A	view · diff
git:20260820.df9ee34	2026-08-20	df9ee34	6,082 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (6175 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

GitHub

marcellocurto/skills · 3 stars · license none declared · pushed 2026-11-03 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_6mn5hdipoyitcenj
GET https://markdownregistry.com/api/v1/resolve?ref=marcellocurto/skills/tdd
GET https://markdownregistry.com/api/v1/blob/4662956a81c6bdfab4a1bf9c132b3e339f79de6146ede05a9f29573dd2d0167e

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.