update API_Documentation

docs/API_Documendation.md

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+# API Documentation
+
+## Base URL
+```
+http://localhost:8000
+```
+
+## Endpoints
+
+### Generate Marketing Copy
+**POST** `/generate`
+
+Generate marketing copy based on prompt and brand guidelines.
+
+#### Request Body
+```json
+{
+  "prompt": "string",
+  "content_type": "general",
+  "tone": "string"
+}
+```
+
+#### Response
+```json
+"Generated marketing copy text"
+```
+
+### Add Campaign
+**POST** `/add-campaign`
+
+Add a marketing campaign to the vector store for future reference.
+
+#### Request Body
+```json
+{
+  "content": "string",
+  "content_type": "string",
+  "metadata": {}
+}
+```
+
+### Search Campaigns
+**GET** `/search`
+
+Search for similar campaigns using vector similarity.
+
+#### Query Parameters
+- `query` (string): Search query
+- `content_type` (string, optional): Filter by content type
+- `k` (int, optional): Number of results to return (default: 3)
+
+#### Response
+```json
+[
+  {
+    "content": "string",
+    "content_type": "string",
+    "metadata": {},
+    "_search_distance": 0.0
+  }
+]
+```
+
+### Health Check
+**GET** `/health`
+
+Check API health status.
+
+#### Response
+```json
+{
+  "status": "healthy"
+}
+```
+
+### Root
+**GET** `/`
+
+API root endpoint with basic information.
+
+## Content Types
+- `general` - General marketing content
+- `email` - Email campaigns
+- `social` - Social media posts
+- `ad` - Advertisement copy
+- `blog` - Blog content
+
+## Error Responses
+All endpoints may return:
+- **422 Validation Error** - Invalid request format
+- **500 Internal Server Error** - Server error
+
+```json
+{
+  "detail": [
+    {
+      "loc": ["field_name"],
+      "msg": "Error message",
+      "type": "error_type"
+    }
+  ]
+}
+```
+
+## Vector Store Features
+- Uses `all-MiniLM-L6-v2` model for embeddings (384 dimensions)
+- FAISS index for fast similarity search
+- Persistent storage of campaigns
+- Automatic index rebuilding on startup