language-kotlin SKILL.md skillA
language-kotlin from lugassawan/swe-workbench is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add lugassawan/swe-workbench/language-kotlin@git:20260828.71a6399Pins git:20260828.71a6399 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- lugassawan/swe-workbench
- Path
skills/language-kotlin/SKILL.md- Versions recorded
- 5
- Latest version
- git:20260828.71a6399, committed Aug 28, 2026
- First version recorded
- Jun 5, 2026
- Size
- 5,238 bytes
- Repository stars
- 3
- License
- MIT
Kotlin idioms — null safety, sealed interfaces, scope functions, and Flow. Auto-load when working with .kt files, build.gradle.kts, or when the user mentions Kotlin, coroutines, StateFlow, or Kotlin DSL.
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
# Kotlin
## Null safety
- `?` makes nullability explicit in the type — `String?` vs `String`.
- Safe-call `?.` returns null instead of throwing. Elvis `?:` provides a default.
- **Never use `!!` in production code** — it is a promise you will never break that can't be verified.
- Jackson does not null-check collection *elements* even with `jackson-module-kotlin` — a declared
`List<Content>` can hold nulls from `{"content":[null]}`. Use `filterNotNull()` (not
`filter { it != null }`, which leaves the type as `List<Content?>`), or
`@JsonSetter(contentNulls = Nulls.SKIP)` at the boundary.
```kotlin
val length = name?.trim()?.length ?: 0
user?.email?.let { send(it) } // null-guard + scoping
val ids = payload.content.filterNotNull().map { it.id }
```
## Data classes and sealed interfaces
- `data class` for value containers: auto-generates `equals`, `hashCode`, `toString`, `copy`, and destructuring.
- `sealed interface` closes a hierarchy and enables exhaustive `when` without an `else` branch.
```kotlin
sealed interface Result<out T>
data class Success<T>(val value: T) : Result<T>
data class Failure(val error: Throwable) : Result<Nothing>
…Read the whole file at its exact version.
How to install
mdr add lugassawan/swe-workbench/language-kotlin@sha256:45c99f8d2d2b32e5The line at the top of this page pins the label git:20260828.71a6399, 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_nusqaetidoo3kqs7)
1 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Jun 5, 2026 and Aug 28, 2026, about one every 21 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260828.71a6399 latest | 2026-08-28 | 71a6399 | 5,238 B | A | view · diff |
| git:20260815.60d7983 | 2026-08-15 | 60d7983 | 5,277 B | A | view · diff |
| git:20260719.e1f78e0 | 2026-07-19 | e1f78e0 | 4,817 B | A | view · diff |
| git:20260623.a686e99 | 2026-06-23 | a686e99 | 4,521 B | A | view · diff |
| git:20260605.400b074 | 2026-06-05 | 400b074 | 4,337 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 (5238 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
lugassawan/swe-workbench · 3 stars · license MIT · pushed 2026-11-07 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_nusqaetidoo3kqs7 GET https://markdownregistry.com/api/v1/resolve?ref=lugassawan/swe-workbench/language-kotlin GET https://markdownregistry.com/api/v1/blob/45c99f8d2d2b32e54f89d735eba00c9cf0592896d1baecfa6380370be97dba3a
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.