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+# Kata 14: The Leak-Free Scheduler
+**Target Idioms:** `time.Timer`/`time.Ticker`, Stop/Reset patterns, Jitter, Context Cancellation  
+**Difficulty:** 🟡 Intermediate
+
+## 🧠 The "Why"
+Scheduling in Go is deceptively easy until you ship:
+- goroutines that never stop,
+- overlapping executions,
+- ticker drift and backlog,
+- resource retention from careless timer usage.
+
+This kata makes you build a scheduler that is **predictable** and **stoppable**.
+
+## 🎯 The Scenario
+You need to periodically refresh a local cache:
+- every 5s, with ±10% jitter
+- do not overlap refreshes
+- stop immediately on shutdown
+
+## 🛠 The Challenge
+Implement:
+- `type Scheduler struct { ... }`
+- `func (s *Scheduler) Run(ctx context.Context, job func(context.Context) error) error`
+
+### 1. Functional Requirements
+- [ ] Run `job` periodically (interval + jitter).
+- [ ] Never run `job` concurrently with itself.
+- [ ] Exit on `ctx.Done()`.
+
+### 2. The "Idiomatic" Constraints (Pass/Fail Criteria)
+- [ ] **Must NOT** use `time.Tick` (no stop control).
+- [ ] **Must** use a `time.Timer` or `time.Ticker` with correct stop/reset.
+- [ ] **Must** propagate context into `job`.
+- [ ] Log job duration and errors via `slog`.
+
+## 🧪 Self-Correction (Test Yourself)
+- **If `job` overlap occurs:** you failed.
+- **If cancel doesn’t stop quickly:** you failed.
+- **If goroutines remain after exit:** you failed.
+
+## 📚 Resources
+- https://pkg.go.dev/time
+- https://go.dev/wiki/Go123Timer