diff --git a/.claude/settings.local.json b/.claude/settings.local.json
new file mode 100644
index 00000000..fad0bef0
--- /dev/null
+++ b/.claude/settings.local.json
@@ -0,0 +1,11 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(dotnet test:*)",
+      "Bash(dotnet build:*)",
+      "Bash(ls:*)",
+      "Bash(find:*)",
+      "Bash(dotnet format:*)"
+    ]
+  }
+}
diff --git a/claude.md b/claude.md
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+BitFaster.Caching provides high performance, thread-safe in-memory caching primitives.
+
+# Development Ethos
+
+- This library is performance first, code is carefully optimized at the expense of readability or maintainability.
+- Meta programming based on generics and structs enable the .NET JIT to elide unused code, devirtualize methods and perform other optimizations. Do not change structs into classes unless explicitly asked.
+- API compatibility is important, unless explicitly asked, assume only additive changes can be made to the public API surface.
+
+# Coding Conventions and Style
+
+- We follow the standard [Microsoft C# Coding Conventions](learn.microsoft.com) and use the built-in `dotnet format` tool to enforce style.
+- **Action Hook:** After generating or modifying any code, you must run `dotnet format` to ensure consistency.