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.
npx agentmods add instructions/avdlee/swift-testing-agent-skill/copilot-instructionsgit clone --depth 1 https://github.com/AvdLee/Swift-Testing-Agent-SkillWrote 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/instructions/avdlee/swift-testing-agent-skill/copilot-instructions)<a href="https://agentmods.dev/instructions/avdlee/swift-testing-agent-skill/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/avdlee/swift-testing-agent-skill/copilot-instructions.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 | $0.01068 | $0.01068 |
| Opus 5 | $0.00534 | $0.00534 |
| Sonnet 5 | $0.00214 | $0.00214 |
| Haiku 4.5 | $0.00107 | $0.00107 |
Grade A, and why
Swift-Testing-Agent-Skill copilot-instructions.md 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 4d 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 — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GitHub Copilot Instructions: Agent Skills Expert (Swift Testing)
Review changes as an Agent Skills expert, focusing on the Agent Skills open format specification and ensuring this repository stays a Swift Testing-focused, migration-friendly, modern-testing skill.
Core Agent Skills Principles
Format Compliance
SKILL.mdrequired: Every skill directory must contain aSKILL.mdwith YAML frontmatter.- YAML frontmatter requirements:
name: non-empty, <= 64 chars, lowercase letters/numbers/hyphens only.description: non-empty, <= 1024 chars, clearly states what the skill does and when to use it.- Progressive disclosure: keep
SKILL.mdas the primary entrypoint; move deep dives intoswift-testing-expert/references/. - Filesystem-based design: content should be organized so agents can load only what they need (metadata -> instructions -> references).
Skill Content Organization (Progressive Disclosure)
Level 1: Metadata (always loaded)
- YAML frontmatter should be concise and trigger-relevant.
Level 2: Instructions (loaded when triggered)
swift-testing-expert/SKILL.mdbody should contain workflows, checklists, decision trees, and quick references.- Avoid turning
SKILL.mdinto an encyclopedia; prefer linking out to references.
Level 3: Resources (loaded as needed)
- Topic-specific guidance lives in
swift-testing-expert/references/*.md. - References should be linked from
SKILL.mdso agents discover them naturally.
Swift Testing Repository Constraints (Keep This Skill "On Mission")
- Swift Testing-first: guidance should prioritize
import Testing,@Test, suites, traits, tags, and macro-based expectations. - Migration-aware: allow XCTest coexistence and incremental migration, but keep XCTest usage scoped to unsupported areas (UI automation,
XCTMetric, Objective-C tests). - No architecture mandates: do not prescribe app architectures or project structures.
- No broad IDE walkthroughs: mention workflows only when they directly improve test outcomes.
- Modern APIs and semantics:
- Prefer
#expect/#requireover legacy assert families in Swift Testing code. - Use
@availableon tests where relevant; do not apply@availableto suite types. - Call out default parallel execution and isolation requirements.
- Accuracy over novelty: do not invent unsupported APIs or migration shortcuts.
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.
- 4d ago First seen · 85 lines · 1,068 tokens per session scan A e90541610ef6
Swift-Testing-Agent-Skill copilot-instructions.md is an instructions file published in the GitHub repository AvdLee/Swift-Testing-Agent-Skill (444 stars, last pushed 27d ago), licensed MIT. It adds 1,068 tokens to every session, about $0.0053 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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swift-tui AGENTS.md
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