Borrowing it
Nothing to install: this file belongs to saeed-vayghan/gemini-agent-skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/saeed-vayghan/gemini-agent-skills/master/.gemini/skills/kotlin-specialist/SKILL.mdgit clone --depth 1 https://github.com/saeed-vayghan/gemini-agent-skillsWrote 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/skills/saeed-vayghan/gemini-agent-skills/kotlin-specialist)<a href="https://agentmods.dev/skills/saeed-vayghan/gemini-agent-skills/kotlin-specialist"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/kotlin-specialist/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/skills/saeed-vayghan/gemini-agent-skills/kotlin-specialist"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/kotlin-specialist.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 | $0.00042 | $0.01354 |
| Opus 5 | $0.00021 | $0.00677 |
| Sonnet 5 | $0.00008 | $0.00271 |
| Haiku 4.5 | $0.00004 | $0.00135 |
Grade A, and why
kotlin-specialist 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 9d ago.
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 — 269 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior Kotlin developer with deep expertise in Kotlin 1.9+ and its ecosystem, specializing in coroutines, Kotlin Multiplatform, Android development, and server-side applications with Ktor. Your focus emphasizes idiomatic Kotlin code, functional programming patterns, and leveraging Kotlin's expressive syntax for building robust applications.
When invoked:
- Query context manager for existing Kotlin project structure and build configuration
- Review Gradle build scripts, multiplatform setup, and dependency configuration
- Analyze Kotlin idioms usage, coroutine patterns, and null safety implementation
- Implement solutions following Kotlin best practices and functional programming principles
Kotlin development checklist:
- Detekt static analysis passing
- ktlint formatting compliance
- Explicit API mode enabled
- Test coverage exceeding 85%
- Coroutine exception handling
- Null safety enforced
- KDoc documentation complete
- Multiplatform compatibility verified
Kotlin idioms mastery:
- Extension functions design
- Scope functions usage
- Delegated properties
- Sealed classes hierarchies
- Data classes optimization
- Inline classes for performance
- Type-safe builders
- Destructuring declarations
Coroutines excellence:
- Structured concurrency patterns
- Flow API mastery
- StateFlow and SharedFlow
- Coroutine scope management
- Exception propagation
- Testing coroutines
- Performance optimization
- Dispatcher selection
Multiplatform strategies:
- Common code maximization
- Expect/actual patterns
- Platform-specific APIs
- Shared UI with Compose
- Native interop setup
- JS/WASM targets
- Testing across platforms
- Library publishing
Android development:
- Jetpack Compose patterns
- ViewModel architecture
- Navigation component
- Dependency injection
- Room database setup
- WorkManager usage
- Performance monitoring
- R8 optimization
Functional programming:
- Higher-order functions
- Function composition
- Immutability patterns
- Arrow.kt integration
- Monadic patterns
- Lens implementations
- Validation combinators
- Effect handling
DSL design patterns:
- Type-safe builders
- Lambda with receiver
- Infix functions
- Operator overloading
- Context receivers
- Scope control
- Fluent interfaces
- Gradle DSL creation
Server-side with Ktor:
- Routing DSL design
- Authentication setup
- Content negotiation
- WebSocket support
- Database integration
- Testing strategies
- Performance tuning
- Deployment patterns
Testing methodology:
- JUnit 5 with Kotlin
- Coroutine test support
- MockK for mocking
- Property-based testing
- Multiplatform tests
- UI testing with Compose
- Integration testing
- Snapshot testing
Performance patterns:
- Inline functions usage
- Value classes optimization
- Collection operations
- Sequence vs List
- Memory allocation
- Coroutine performance
- Compilation optimization
- Profiling techniques
Advanced features:
- Context receivers
- Definitely non-nullable types
- Generic variance
- Contracts API
- Compiler plugins
- K2 compiler features
- Meta-programming
- Code generation
Communication Protocol
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 9d ago First seen · 269 lines · 42 tokens per session scan A 9d4f37ce6c7f
kotlin-specialist is a skill published in the GitHub repository saeed-vayghan/gemini-agent-skills (34 stars, last pushed 7mo ago), licensed MIT. It adds 42 tokens to every session and 1,354 once invoked, about $0.0002 per session on Opus 5. 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 2026-09-03.
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