## Summary
Two small additive changes that an external content assembly (ModernSpawner) needs, as separable commits.
**1. `SkillEvents.SkillUsed`** (`Projects/UOContent/Skills/SkillEvents.cs`, namespace `Server.Misc`): a plain C# event `Action<Mobile, Skill, bool success>` raised once per skill attempt from each of the four `Mobile_SkillCheck*` handlers, with the handler's own result. Attempts the handler resolves without a roll (too difficult, no challenge) raise too, so a grandmaster's trivial success and a guaranteed combat roll are observable. Not raised when the mobile lacks the skill. Each handler keeps its logic in a private core method and raises on the way out, so there is exactly one raise per attempt and `CheckSkill` itself is unchanged.
- **Why a plain event and not a `[GeneratedEvent]`:** generated events are compile-time static dispatch inside the UOContent compilation, so a subscriber in another assembly cannot use `[OnEvent]`. Shape follows `HelpEvents`.
- **Why "used", not "gained":** this is the XmlSpawner skill-trigger semantic (it wrapped the same four handlers and passed their result as `success`; its grammar was `Skill[+/-]` for success-only or failure-only). Gains are already observable through the existing skill-change notification on `Mobile`.
- **Cost:** one delegate null-check per attempt when nothing is subscribed; no boxing, no closure, no allocation. The handlers sit on the combat swing path.
- **Exception contract:** subscriber exceptions propagate, matching `EventSink`/`HelpEvents`; no try/catch by design.
**2. `InternalsVisibleTo("ModernSpawner.Tests")`** on `Server.csproj`, beside the existing `Server.Tests`/`UOContent.Tests` entries, so an external test host can seed `Core._now` the way the engine's own test initializers do. Separable; a public test seam on `Core` would serve the same need without naming a downstream assembly.
## Open question
The payload is the `Skill` object plus a positional `bool`. A `readonly struct` args type passed `in` would leave room to add `chance` or the target later without breaking subscribers. Happy to change before merge.
## Test plan
- [x] `UOContent.Tests`: 4 tests — a rolled attempt raises once with the returned outcome; each short-circuit path (no challenge, too difficult, on both the direct and value-window handlers) raises with the handler's result; a direct `CheckSkill` call does not raise; no subscriber does not throw. Full suite green.
- [x] `Server` and `UOContent` build clean with `TreatWarningsAsErrors`.
- [ ] CI
Summary
- Adds CLAUDE.md at repo root with 14 terse code audit rules (always loaded, low token cost)
- Adds pointer files for other AI tools: AGENTS.md (Codex), GEMINI.md, .github/COPILOT-INSTRUCTIONS.md (Copilot), .cursorrules (Cursor) — all redirect to CLAUDE.md as single source of truth
- Gitignores /.claude so personal AI config isn't distributed
- Moves Claude skills to dev-docs/claude-skills/ (opt-in, not auto-loaded)
- Adds 14 dev-docs covering codebase conventions
Code Audit Rules (in CLAUDE.md)
1. LINQ tiered rules (Tier 1 free, Tier 2 warm, Tier 3 forbidden)
2. No Console.WriteLine — use LogFactory.GetLogger()
3. No concurrency primitives in game code
4. No World.Mobiles/World.Items iteration
5. Clean up refs in OnDelete()/OnAfterDelete()
6. Cancel timers in OnDelete()/OnAfterDelete()
7. STArrayPool<T>.Shared not ArrayPool<T>.Shared
8. PooledRefList<T> not new List<T>() on hot paths
9. Serialization: partial class, [Constructible], no serialized TimerExecutionToken
10. No Task.Run/new Thread() in game code
11. Never assume era — ask which expansion
12. _camelCase fields, PascalCase properties/methods
13. No empty gumps — use DisplayTo() pattern
14. PropertyList string literals must be {} holes, cliloc-as-argument uses :#
