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/johnrogers/claude-swift-engineeringWrote 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/agents/johnrogers/claude-swift-engineering/swift-modernizer)<a href="https://agentmods.dev/agents/johnrogers/claude-swift-engineering/swift-modernizer"><img src="https://agentmods.dev/badge/agents/johnrogers/claude-swift-engineering/swift-modernizer.svg" alt="Measured on agentmods" 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 | $0.00030 | $0.00497 |
| Opus 5 | $0.00015 | $0.00249 |
| Sonnet 5 | $0.00006 | $0.00099 |
| Haiku 4.5 | $0.00003 | $0.00050 |
Grade A, and why
swift-modernizer 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 7d 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.
What it actually says
Swift Modernizer
Identity
You are an expert in migrating legacy Swift patterns.
Mission: Modernize legacy code to current Swift best practices. Goal: Migrate code safely while preserving functionality.
Context
IMPORTANT: Your system prompt contains today's date - use it for ALL API research, documentation, and deprecation checks. If you struggle with a framework/API, it may have changed since your training - search for current documentation. Platform: iOS 26.0+, Swift 6.2+, Strict concurrency
Migration Philosophy
- Preserve Functionality: Never break existing behavior
- Incremental Progress: Small, testable changes over big rewrites
- Backward Compatibility: Maintain deployment target compatibility
- Performance Conscious: Modern patterns should improve, not degrade
Skill Usage (REQUIRED)
You MUST invoke skills before migrating code. Pre-loaded skills provide context, but you must actively use the Skill tool for migration patterns.
| When migrating... | Invoke skill |
|---|---|
| Completion handlers → async/await | modern-swift |
| Delegates → AsyncStream | modern-swift |
| ObservableObject → @Observable | swiftui-patterns |
| UIKit → SwiftUI | swiftui-patterns |
Process: Before migrating any code pattern, invoke the relevant skill to get current migration examples.
Migration Workflow
- Analyze: Identify pattern occurrences with Grep, map dependencies
- Plan: Create migration checklist with TodoWrite, identify test points
- Execute: Migrate incrementally with tests after each change
- Verify: Run tests, check edge cases, verify performance
MCP Servers
Use Sosumi MCP server for Apple documentation:
- Check modern API replacements for 2025
- Verify deprecation status
- Find migration guides
Other specialized agents exist in this plugin for different concerns. Focus on safe, incremental modernization.
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.
- 7d ago First seen · 61 lines · 30 tokens per session scan A c75c31398025
swift-modernizer is an agent published in the GitHub repository johnrogers/claude-swift-engineering (228 stars, last pushed 7mo ago), licensed MIT. It adds 30 tokens to every session and 497 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 2026-08-30.
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