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Agent skill

Kotlin Best Practices

by c0x12c in c0x12c/ai-toolkit

Kotlin coding standards including null safety, Either error handling, coroutines, and Exposed ORM patterns.

No licenceAuto-check passedMobile

Install Kotlin Best Practices

skills CLI
$ npx skills add c0x12c/ai-toolkit --skill kotlin-best-practices -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install c0x12c/ai-toolkit kotlin-best-practices --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/c0x12c/ai-toolkit.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.codex/skills/kotlin-best-practices .claude/skills/kotlin-best-practices && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
kotlin-best-practices
GitHub stars
106
Token cost
~438 tokens
SKILL.md length
175 words
Files
2
Skills in repo
33
Repo updated
First seen
Licence
None found

At a glance

Kotlin coding standards including null safety, Either error handling, coroutines, and Exposed ORM patterns.

  • Writing Kotlin code
  • SKILL.md covers Null Safety, Either Error Handling, Enum Usage and Exposed ORM Patterns, plus 3 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • Reviewing code quality

What it does

Kotlin Best Practices is an agent skill from c0x12c/ai-toolkit. Kotlin coding standards including null safety, Either error handling, coroutines, and Exposed ORM patterns. Use when writing Kotlin code, reviewing code quality, or learning project patterns.

Its SKILL.md is about 440 tokens, which your agent loads only when the skill is triggered. The skill folder holds 1 other file (for example `code-patterns.md`).

It sits in Mobile, covering Android development, Code quality and ORMs and data access. It works with Kotlin.

When your agent uses it

  • Writing Kotlin code
  • Reviewing code quality
  • Learning project patterns

Example prompts

  • “/kotlin-best-practices”

What it can do on your machine

Read from SKILL.md and the folder at commit 96b2c9d. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Kotlin Best Practices loads about 438 tokens when it runs. Until then it costs about 53 tokens; SKILL.md has 175 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~53
When it runs · the whole SKILL.md, loaded when a task matches
~438

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Without a licence we can't republish the file, so here is its outline and opening line. It has 175 words (~438 tokens).

“!! is banned. Use ?., ?:, or null check for smart cast.”

— opening of SKILL.md by c0x12c
name
kotlin-best-practices

Read the full SKILL.md on GitHub

Files

SKILL.md and 1 other file in .codex/skills/kotlin-best-practices of c0x12c/ai-toolkit.

  • SKILL.md
  • code-patterns.md

Open the folder on GitHubat commit 96b2c9d

Compare with similar skills

Kotlin Best Practices next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Kotlin Best Practices compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Kotlin Best Practices this skillc0x12c/ai-toolkit106—~438Automated safety check: PassNone
Dart Coding Standardsbladeofgod/flutter-ai-harness116—~228Automated safety check: PassMIT
Code Revieweralirezarezvani/claude-skills28k1 repos~1.6kAutomated safety check: PassMIT
Kotlin Tooling Java To KotlinJetBrains/skills3663 repos~1.4kAutomated safety check: PassApache-2.0
Kotlin Backend Jpa Entity MappingJetBrains/skills3662 repos~1.8kAutomated safety check: PassApache-2.0
Code Reviewerborghei/Claude-Skills891—~1.7kAutomated safety check: PassMIT

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Works with

Categories

Questions about Kotlin Best Practices

What does Kotlin Best Practices do?

Kotlin coding standards including null safety, Either error handling, coroutines, and Exposed ORM patterns. Kotlin Best Practices is an agent skill from c0x12c/ai-toolkit. Kotlin coding standards including null safety, Either error handling, coroutines, and Exposed ORM patterns.

When should I use Kotlin Best Practices?

Kotlin Best Practices fits situations like: writing Kotlin code; reviewing code quality; learning project patterns.

How do I install Kotlin Best Practices in Claude Code?

Run `npx skills add c0x12c/ai-toolkit --skill kotlin-best-practices -a claude-code`. Or copy the skill folder (.codex/skills/kotlin-best-practices in c0x12c/ai-toolkit) into .claude/skills/kotlin-best-practices in your project. Claude Code loads it when a task matches its description.

How do I install Kotlin Best Practices in Codex?

Run `npx skills add c0x12c/ai-toolkit --skill kotlin-best-practices -a codex`. Or copy the skill folder (.codex/skills/kotlin-best-practices in c0x12c/ai-toolkit) into .agents/skills/kotlin-best-practices in your project. Codex loads it when a task matches its description.

Can I use Kotlin Best Practices in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add c0x12c/ai-toolkit --skill kotlin-best-practices -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/kotlin-best-practices, .gemini/skills/kotlin-best-practices, .github/skills/kotlin-best-practices and .opencode/skills/kotlin-best-practices in your project.

What does Kotlin Best Practices need to run?

SKILL.md names no scripts, command-line tools or credentials: Kotlin Best Practices is instructions for the agent only.

Does Kotlin Best Practices access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Kotlin Best Practices safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Kotlin Best Practices use?

No licence was found for Kotlin Best Practices or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.

How many tokens does Kotlin Best Practices use?

About 438 tokens (SKILL.md is roughly 1.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Kotlin Best Practices?

Skills that share tags, products or a category with Kotlin Best Practices: Dart Coding Standards (bladeofgod/flutter-ai-harness, 116 stars), Code Reviewer (alirezarezvani/claude-skills, 28k stars), Kotlin Tooling Java To Kotlin (JetBrains/skills, 366 stars) and Kotlin Backend Jpa Entity Mapping (JetBrains/skills, 366 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Kotlin Best Practices?

c0x12c (a GitHub organization) maintains it in c0x12c/ai-toolkit, which has 106 GitHub stars. The repository holds 33 skills in this directory. The repository was last updated on June 18, 2026.

Source: c0x12c/ai-toolkit on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.