Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/beel-collab/presets.devWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/beel-collab/presets.dev/kotlin-rules)<a href="https://agentmods.dev/rules/beel-collab/presets.dev/kotlin-rules"><img src="https://agentmods.dev/badge/rules/beel-collab/presets.dev/kotlin-rules/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/beel-collab/presets.dev/kotlin-rules"><img src="https://agentmods.dev/badge/rules/beel-collab/presets.dev/kotlin-rules.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00000 | $0.01058 |
| Opus 5.5 | $0.00000 | $0.00423 |
| Sonnet 5.5 | $0.00000 | $0.00212 |
| Haiku 4.5 | $0.00000 | $0.00106 |
Grade A, and why
kotlin-rules scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Kotlin Rules for Cursor: Coroutines, Null Safety and Compose
Install
Install the native export at .cursor/rules/kotlin-rules.mdc.
Copy that export, not this catalog file. Catalog fields such as tools and author are for presets.dev.
Install one skill file per name. Cursor, GitHub Copilot, Codex, Antigravity CLI, and Devin can all read .agents/skills, so a second copy with the same name collides.
Kotlin Rules for Cursor: Coroutines, Null Safety and Compose
File-scoped Cursor rule for Kotlin. It attaches when a matching file is in context.
Updated for Kotlin 2.4, Nov 2026
Do not upgrade dependencies or the framework version unless the task asks.
Stay on the Kotlin version the Gradle build uses. Kotlin 2.4.20 adds StackTraceRecoverable for coroutine stack traces. That API is experimental and requires @OptIn(ExperimentalStdlibCoroutineSupportApi::class). It is not on by default. Swift export is the other 2.4.20 change. Use either only when the compiler is already on 2.4. A multiplatform target is added only when the project is already multiplatform.
Project shape
Match the source sets. Android UI uses the Compose compiler the project already applies. A ViewModel or the project's presenter owns screen state. A composable displays state and sends events up. Do not fetch the network directly inside a composable.
Coroutines
Launch in a scope that is canceled with the owner: viewModelScope, lifecycleScope, or a scope the class cancels in close. GlobalScope is a bug. runBlocking does not belong inside a suspend function or on the main thread.
A coroutine checks cancellation. Do not catch Exception and ignore CancellationException. Rethrow it. A Flow is collected in repeatOnLifecycle or the project's equivalent so it stops when the screen stops. A hot flow shared with shareIn has a stopping policy.
Null and errors
Prefer ?. and a real branch over !!. !! is a crash you chose. A public function returns a sealed result or throws the project's exception. Do not return null for three different failures.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today First seen · 107 lines · 0 tokens per session scan A d0cf00142274
kotlin-rules is a cursor rule published in the GitHub repository beel-collab/presets.dev (3 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,058 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-11-13.
kotlin-rules compared with cursor rules from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| kotlin-rulesbeel-collab/presets.dev | Cursor rule | 3 | yesterday | MIT | A | 0 | Cursor |
| compose-coroutinesbaijum/ukulele-companion | Cursor rule | 14 | 8d ago | MIT | A | 0 | Cursor |
| ios-viewmodelbaijum/ukulele-companion | Cursor rule | 14 | 8d ago | MIT | A | 0 | Cursor |
| android-viewmodelbaijum/ukulele-companion | Cursor rule | 14 | 8d ago | MIT | A | 0 | Cursor |
| cursorrulesRanaNadeemAslam/android-ai-skills | Cursor rule | 5 | 7mo ago | MIT | A | 15,269 | Cursor |
| shared-modulebaijum/ukulele-companion | Cursor rule | 14 | 8d ago | MIT | A | 0 | Cursor |
| androidAcKeskin/contexture | Cursor rule | 2 | today | MIT | A | 879 | Cursor |