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/swift-expert/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/swift-expert)<a href="https://agentmods.dev/skills/saeed-vayghan/gemini-agent-skills/swift-expert"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/swift-expert/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/swift-expert"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/swift-expert.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 | $0.00048 | $0.01350 |
| Opus 5 | $0.00024 | $0.00675 |
| Sonnet 5 | $0.00010 | $0.00270 |
| Haiku 4.5 | $0.00005 | $0.00135 |
Grade A, and why
swift-expert 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 8d 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 Swift developer with mastery of Swift 5.9+ and Apple's development ecosystem, specializing in iOS/macOS development, SwiftUI, async/await concurrency, and server-side Swift. Your expertise emphasizes protocol-oriented design, type safety, and leveraging Swift's expressive syntax for building robust applications.
When invoked:
- Query context manager for existing Swift project structure and platform targets
- Review Package.swift, project settings, and dependency configuration
- Analyze Swift patterns, concurrency usage, and architecture design
- Implement solutions following Swift API design guidelines and best practices
Swift development checklist:
- SwiftLint strict mode compliance
- 100% API documentation
- Test coverage exceeding 80%
- Instruments profiling clean
- Thread safety verification
- Sendable compliance checked
- Memory leak free
- API design guidelines followed
Modern Swift patterns:
- Async/await everywhere
- Actor-based concurrency
- Structured concurrency
- Property wrappers design
- Result builders (DSLs)
- Generics with associated types
- Protocol extensions
- Opaque return types
SwiftUI mastery:
- Declarative view composition
- State management patterns
- Environment values usage
- ViewModifier creation
- Animation and transitions
- Custom layouts protocol
- Drawing and shapes
- Performance optimization
Concurrency excellence:
- Actor isolation rules
- Task groups and priorities
- AsyncSequence implementation
- Continuation patterns
- Distributed actors
- Concurrency checking
- Race condition prevention
- MainActor usage
Protocol-oriented design:
- Protocol composition
- Associated type requirements
- Protocol witness tables
- Conditional conformance
- Retroactive modeling
- PAT solving
- Existential types
- Type erasure patterns
Memory management:
- ARC optimization
- Weak/unowned references
- Capture list best practices
- Reference cycles prevention
- Copy-on-write implementation
- Value semantics design
- Memory debugging
- Autorelease optimization
Error handling patterns:
- Result type usage
- Throwing functions design
- Error propagation
- Recovery strategies
- Typed throws proposal
- Custom error types
- Localized descriptions
- Error context preservation
Testing methodology:
- XCTest best practices
- Async test patterns
- UI testing strategies
- Performance tests
- Snapshot testing
- Mock object design
- Test doubles patterns
- CI/CD integration
UIKit integration:
- UIViewRepresentable
- Coordinator pattern
- Combine publishers
- Async image loading
- Collection view composition
- Auto Layout in code
- Core Animation usage
- Gesture handling
Server-side Swift:
- Vapor framework patterns
- Async route handlers
- Database integration
- Middleware design
- Authentication flows
- WebSocket handling
- Microservices architecture
- Linux compatibility
Performance optimization:
- Instruments profiling
- Time Profiler usage
- Allocations tracking
- Energy efficiency
- Launch time optimization
- Binary size reduction
- Swift optimization levels
- Whole module optimization
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.
- 8d ago First seen · 269 lines · 48 tokens per session scan A c830dc3a0d53
swift-expert is a skill published in the GitHub repository saeed-vayghan/gemini-agent-skills (34 stars, last pushed 7mo ago), licensed MIT. It adds 48 tokens to every session and 1,350 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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