behavior-implement SKILL.md skillA
behavior-implement from yarlson/yarstack is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add yarlson/yarstack/behavior-implement@git:20261017.2f2e03bPins git:20261017.2f2e03b in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- yarlson/yarstack
- Path
plugins/yarstack/skills/behavior-implement/SKILL.md- Versions recorded
- 7
- Latest version
- git:20261017.2f2e03b, committed Oct 17, 2026
- First version recorded
- Jul 24, 2026
- Size
- 2,873 bytes
- Repository stars
- 3
- License
- MIT
Implement one observable behavior or bug fix with red-green-refactor, writing a focused test that fails first, the minimum code that passes it, and then a behavior-preserving cleanup. Use for product behavior changes; for tooling or infrastructure, use it only when native checks such as linters, validators, dry runs, or plans cannot show the behavior.
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 Implementation Implement one coherent observable behavior and prove it with a test that failed before the change and passes after it. ## Workflow 1. Read the behavior contract, the repository instructions, the closest implementation and test patterns, and the callers of the code you will change. 2. For tooling or infrastructure, prove the change with the native checks and skip the red test, unless those checks cannot show behavior that matters. 3. Define the observable result, the side effects, and the state that must stay unchanged on failure. Rely only on the documented behavior of dependencies. 4. Choose the smallest mechanism, and stop at the first option that works: no change, existing code, the standard library or platform, an installed dependency, or one clear line. Never drop validation, data-loss prevention, security, accessibility, or an explicit requirement to make the change smaller. If the contract needs much more scope than expected, explain the gap and ask for direction instead of building an approximation. 5. Use `test-design` when the test level, cases, or fixtures are not obvious. Otherwise extend the existing test pattern. …
Read the whole file at its exact version.
How to install
mdr add yarlson/yarstack/behavior-implement@sha256:192ec2fc0af0b078The line at the top of this page pins the label git:20261017.2f2e03b, 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_zwtinrcm24qevfzp)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 7 versions of this file, between Jul 24, 2026 and Oct 17, 2026, about one every 14 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261017.2f2e03b latest | 2026-10-17 | 2f2e03b | 2,873 B | A | view · diff |
| git:20260912.ee51a98 | 2026-09-12 | ee51a98 | 2,666 B | A | view · diff |
| git:20260911.e22616f | 2026-09-11 | e22616f | 3,597 B | A | view · diff |
| git:20260724.a1b6f43 | 2026-07-24 | a1b6f43 | 3,397 B | A | view · diff |
| git:20260724.d8cd6d9 | 2026-07-24 | d8cd6d9 | 3,187 B | A | view · diff |
| git:20260724.0771972 | 2026-07-24 | 0771972 | 2,685 B | A | view · diff |
| git:20260724.88cc4a2 | 2026-07-24 | 88cc4a2 | 2,469 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 (2873 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
yarlson/yarstack · 3 stars · license MIT · pushed 2026-10-19 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_zwtinrcm24qevfzp GET https://markdownregistry.com/api/v1/resolve?ref=yarlson/yarstack/behavior-implement GET https://markdownregistry.com/api/v1/blob/192ec2fc0af0b078523394ec08b0380a42a46eb952d26ae39c2e3625191c1359
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.