Simplify fetch prompt-caching README to link to main docs

Author: subtleGradient

typescript/fetch/src/prompt-caching/README.md

@@ -1,98 +1,27 @@
-# Anthropic Prompt Caching Examples
+# Prompt Caching Examples (TypeScript + fetch)
 
-This directory contains examples demonstrating Anthropic's prompt caching feature via OpenRouter using the raw fetch API.
+Examples demonstrating prompt caching with the fetch API.
 
-## What is Prompt Caching?
+## Documentation
 
-Anthropic's prompt caching allows you to cache large portions of your prompts (like system messages or context documents) to:
-- **Reduce costs** - Cached tokens cost significantly less than regular tokens
-- **Improve latency** - Cached content is processed faster on subsequent requests
-- **Enable larger contexts** - Use more context without proportional cost increases
+For full prompt caching documentation including all providers, pricing, and configuration details, see:
+- **[Prompt Caching Guide](../../../../docs/prompt-caching.md)**
 
-Cache TTL: 5 minutes for ephemeral caches
+## Examples in This Directory
 
-## Examples
+- `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)
 
-### 1. System Message Cache (`system-message-cache.ts`)
-The most common pattern - cache a large system prompt:
-```bash
-bun run typescript/fetch/src/prompt-caching/system-message-cache.ts
-```
-
-**Pattern**: System message with content-level `cache_control`
+## Quick Start
 
-### 2. User Message Cache (`user-message-cache.ts`)
-Cache large context in user messages (e.g., uploading documents):
 ```bash
+# Run an example
 bun run typescript/fetch/src/prompt-caching/user-message-cache.ts
 ```
 
-**Pattern**: User message with content-level `cache_control` on context block
-
-### 3. Multi-Message Cache (`multi-message-cache.ts`)
-Cache system prompt across multi-turn conversations:
-```bash
-bun run typescript/fetch/src/prompt-caching/multi-message-cache.ts
-```
-
-**Pattern**: System message cache persists through conversation history
-
-### 4. No Cache Control (`no-cache-control.ts`)
-Control scenario - no caching should occur:
-```bash
-bun run typescript/fetch/src/prompt-caching/no-cache-control.ts
-```
-
-**Pattern**: Same structure but NO `cache_control` markers (validates methodology)
-
-## How to Use Cache Control
-
-```typescript
-const requestBody = {
-  model: 'anthropic/claude-3.5-sonnet',
-  stream_options: {
-    include_usage: true, // CRITICAL: Required for cache metrics
-  },
-  messages: [
-    {
-      role: 'system',
-      content: [
-        {
-          type: 'text',
-          text: 'Your large system prompt here...',
-          cache_control: { type: 'ephemeral' }, // Cache this block
-        },
-      ],
-    },
-    {
-      role: 'user',
-      content: 'Your question here',
-    },
-  ],
-};
-```
-
-## Important Notes
-
-### OpenRouter Format Transformation
-OpenRouter transforms Anthropic's native response format to OpenAI-compatible format:
-- **Anthropic native**: `usage.cache_read_input_tokens`, `usage.cache_creation_input_tokens`
-- **OpenRouter returns**: `usage.prompt_tokens_details.cached_tokens` (OpenAI-compatible)
-
-### Requirements for Caching
-1. **stream_options.include_usage = true** - CRITICAL, otherwise no usage details
-2. **Minimum 2048+ tokens** - Smaller content may not be cached reliably
-3. **cache_control on content blocks** - Not on message level
-4. **Exact match** - Cache only hits on identical content
-
-### Expected Behavior
-- **First call**: `cached_tokens = 0` (cache miss, creates cache)
-- **Second call**: `cached_tokens > 0` (cache hit, reads from cache)
-- **Control**: `cached_tokens = 0` on both calls (no cache_control)
+## Key Requirements (Anthropic)
 
-## Scientific Method
-All examples follow scientific method principles:
-- **Hypothesis**: cache_control triggers Anthropic caching
-- **Experiment**: Make identical calls twice
-- **Evidence**: Measure via `usage.prompt_tokens_details.cached_tokens`
-- **Analysis**: Compare first call (miss) vs second call (hit)
+- `stream_options.include_usage = true` - Required for cache metrics
+- Minimum 2048+ tokens to cache reliably
+- `cache_control: {type: "ephemeral"}` on content blocks (not message-level)