Add prompt-caching placeholder for OpenRouter SDK

docs/prompt-caching.md

@@ -190,3 +190,4 @@ See ecosystem-specific examples:
 - **TypeScript + fetch**: [typescript/fetch/src/prompt-caching/](../typescript/fetch/src/prompt-caching/)
 - **AI SDK v5** (Vercel): [typescript/ai-sdk-v5/src/prompt-caching/](../typescript/ai-sdk-v5/src/prompt-caching/)
 - **Effect AI** (@effect/ai): [typescript/effect-ai/src/prompt-caching/](../typescript/effect-ai/src/prompt-caching/)
+- **OpenRouter SDK** (@openrouter/sdk): [typescript/openrouter-sdk/src/prompt-caching/](../typescript/openrouter-sdk/src/prompt-caching/)

typescript/openrouter-sdk/README.md

@@ -0,0 +1,16 @@
+# OpenRouter TypeScript SDK Examples
+
+Examples using the official @openrouter/sdk package.
+
+## Status
+
+**TODO**: Examples not yet implemented
+
+## Prerequisites
+
+- Bun runtime: `curl -fsSL https://bun.sh/install | bash`
+- `OPENROUTER_API_KEY` environment variable
+
+## Planned Features
+
+- [ ] prompt-caching.ts - Anthropic caching with OpenRouter SDK

typescript/openrouter-sdk/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "@openrouter-examples/openrouter-sdk",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "examples": "echo 'TODO: OpenRouter SDK examples not yet implemented'"
+  },
+  "dependencies": {
+    "@openrouter-examples/shared": "workspace:*"
+  },
+  "devDependencies": {
+    "@types/bun": "latest"
+  }
+}

typescript/openrouter-sdk/src/prompt-caching/README.md

@@ -0,0 +1,28 @@
+# Prompt Caching Examples (OpenRouter SDK)
+
+Examples demonstrating prompt caching with @openrouter/sdk.
+
+## Documentation
+
+For full prompt caching documentation including all providers, pricing, and configuration details, see:
+- **[Prompt Caching Guide](../../../../docs/prompt-caching.md)**
+
+## Status
+
+**TODO**: Examples coming soon. This directory will contain:
+- `user-message-cache.ts` - Cache large context in user messages
+- `multi-message-cache.ts` - Cache system prompt across multi-turn conversations
+- `no-cache-control.ts` - Control scenario (validates methodology)
+
+## Expected Usage
+
+```typescript
+import OpenRouter from '@openrouter/sdk';
+
+const openrouter = new OpenRouter({
+  apiKey: process.env.OPENROUTER_API_KEY,
+});
+
+// Configuration and cache_control usage pattern will be documented
+// when examples are implemented
+```

typescript/package.json

@@ -13,7 +13,8 @@
     "shared",
     "fetch",
     "ai-sdk-v5",
-    "effect-ai"
+    "effect-ai",
+    "openrouter-sdk"
   ],
   "devDependencies": {
     "@types/bun": "latest",