# MCP Server > Generic MCP (Model Context Protocol) server development patterns. Provides reusable architecture and best practices for building MCP servers that expose any domain-specific operations as tools for AI agents. Framework-agnostic implementation supporting async operations, error handling, and enterprise-grade features. - Skill: `aiskillstore/mcp-server` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add aiskillstore/mcp-server` - Raw SKILL.md: https://api.skillmd.com/api/skills/aiskillstore/mcp-server/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - License: MIT - Author: aiskillstore (https://skillmd.com/u/aiskillstore) - Updated: 2026-09-08 - Page: https://skillmd.com/skills/aiskillstore/mcp-server --- # Generic MCP Server Development This skill provides comprehensive patterns and reusable code for building MCP (Model Context Protocol) servers that can expose any domain operations as tools for AI agents. Follows 2025 best practices for performance, security, and maintainability. ## When to Use This Skill Use this skill when you need to: - Build an MCP server for any domain (not just todos) - Expose database operations as MCP tools - Create AI-agent accessible APIs - Implement async MCP tool handlers - Add proper error handling and validation - Support rate limiting and caching - Build enterprise-grade MCP servers - Integrate with multiple storage backends ## 1. Generic MCP Server Architecture ```python # mcp_server/core.py #!/usr/bin/env python3 """ Generic MCP Server Base Architecture Provides reusable patterns for any MCP server implementation """ import asyncio import json import logging from abc import ABC, abstractmethod from datetime import datetime, timedelta from typing import Any, Dict, List, Optional, Sequence, Union, Callable from contextlib import asynccontextmanager from dataclasses import dataclass, field from enum import Enum import redis.asyncio as redis from mcp.server import Server, NotificationOptions, stdio from mcp.server.models import InitializationOptions from mcp.server.stdio import stdio_server from mcp.types import ( Resource, Tool, TextContent, ImageContent, EmbeddedResource, LoggingLevel, CallToolRequest, EmptyResult, ListResourcesRequest, ListToolsRequest, ReadResourceRequest, GetPromptRequest, ListPromptsRequest ) from pydantic import BaseModel, Field, validator import aiofiles import yaml from pathlib import Path # Configure logging logging.basicConfig( level=logging.INFO, format="%(asctime)s - %(name)s - %(levelname)s - %(message)s" ) logger = logging.getLogger("mcp_server") class ServerConfig(BaseModel): """MCP Server configuration""" name: str version: str = "1.0.0" description: str debug: bool = False redis_url: Optional[str] = None rate_limit_requests: int = 100 rate_limit_window: int = 60 cache_ttl: int = 300 max_retries: int = 3 timeout: int = 30 class Config: extra = "allow" @dataclass class RequestContext: """Request context for tool calls""" user_id: str session_id: Optional[str] = None metadata: Dict[str, Any] = field(default_factory=dict) timestamp: datetime = field(default_factory=datetime.utcnow) class RateLimiter: """Redis-based rate limiter for MCP operations""" def __init__(self, redis_url: str, requests: int, window: int): self.redis_url = redis_url self.requests = requests self.window = window self._redis = None async def _get_redis(self): if not self._redis: self._redis = await redis.from_url(self.redis_url) return self._redis async def is_allowed(self, key: str) -> bool: """Check if request is allowed""" r = await self._get_redis() current = await r.incr(f"rate_limit:{key}") if current == 1: await r.expire(f"rate_limit:{key}", self.window) return current <= self.requests async def get_remaining(self, key: str) -> int: """Get remaining requests""" r = await self._get_redis() current = await r.get(f"rate_limit:{key}") return max(0, self.requests - int(current or 0)) class CacheManager: """Redis-based caching for MCP responses""" def __init__(self, redis_url: str, ttl: int = 300): self.redis_url = redis_url self.ttl = ttl self._redis = None async def _get_redis(self): if not self._redis: self._redis = await redis.from_url(self.redis_url) return self._redis def _make_key(self, tool_name: str, args: Dict[str, Any]) -> str: """Generate cache key from tool name and arguments""" import hashlib args_str = json.dumps(args, sort_keys=True) return f"cache:{tool_name}:{hashlib.md5(args_str.encode()).hexdigest()}" async def get(self, tool_name: str, args: Dict[str, Any]) -> Optional[Any]: """Get cached result""" r = await self._get_redis() key = self._make_key(tool_name, args) result = await r.get(key) return json.loads(result) if result else None async def set(self, tool_name: str, args: Dict[str, Any], value: Any): """Cache result""" r = await self._get_redis() key = self._make_key(tool_name, args) await r.setex(key, self.ttl, json.dumps(value)) class BaseMCPServer: """Base MCP Server with common functionality""" def __init__(self, config: ServerConfig): self.config = config self.server = Server(config.name) self.tools: Dict[str, Callable] = {} self.rate_limiter: Optional[RateLimiter] = None self.cache: Optional[CacheManager] = None # Setup optional components if config.redis_url: self.rate_limiter = RateLimiter( config.redis_url, config.rate_limit_requests, config.rate_limit_window ) self.cache = CacheManager( config.redis_url, config.cache_ttl ) # Register handlers self._register_handlers() logger.info(f"MCP Server '{config.name}' initialized") def _register_handlers(self): """Register MCP handlers""" @self.server.list_tools() async def handle_list_tools() -> List[Tool]: """Return list of available tools""" return await self.list_tools() @self.server.call_tool() async def handle_call_tool(name: str, arguments: Dict[str, Any]) -> List[TextContent]: """Handle tool call with rate limiting and caching""" return await self.call_tool(name, arguments) def register_tool(self, name: str, handler: Callable, schema: Dict[str, Any]): """Register a new tool""" self.tools[name] = { "handler": handler, "schema": schema } logger.info(f"Registered tool: {name}") async def list_tools(self) -> List[Tool]: """List all available tools""" tools = [] for name, tool_info in self.tools.items(): tools.append(Tool( name=name, description=tool_info["schema"].get("description", ""), inputSchema=tool_info["schema"].get("inputSchema", {}) )) return tools async def call_tool(self, name: str, arguments: Dict[str, Any]) -> List[TextContent]: """Execute a tool call with full middleware pipeline""" start_time = datetime.utcnow() try: # Extract context from arguments context = self._extract_context(arguments) # Rate limiting check if self.rate_limiter: rate_key = f"{context.user_id}:{name}" if not await self.rate_limiter.is_allowed(rate_key): return [TextContent( type="text", text=json.dumps({ "status": "error", "error": "Rate limit exceeded", "remaining": await self.rate_limiter.get_remaining(rate_key) }) )] # Check cache if self.cache and self._is_cacheable(name): cached_result = await self.cache.get(name, arguments) if cached_result: logger.info(f"Cache hit for tool: {name}") return [TextContent( type="text", text=json.dumps(cached_result) )] # Validate tool exists if name not in self.tools: raise ValueError(f"Unknown tool: {name}") # Validate arguments schema = self.tools[name]["schema"] self._validate_arguments(arguments, schema) # Execute tool handler = self.tools[name]["handler"] result = await self._execute_tool(handler, arguments, context) # Cache result if applicable if self.cache and self._is_cacheable(name) and result.get("status") != "error": await self.cache.set(name, arguments, result) # Log execution duration = (datetime.utcnow() - start_time).total_seconds() logger.info(f"Tool {name} executed in {duration:.2f}s for user {context.user_id}") return [TextContent( type="text", text=json.dumps(result, default=str) )] except Exception as e: logger.error(f"Error executing tool {name}: {str(e)}", exc_info=True) duration = (datetime.utcnow() - start_time).total_seconds() logger.error(f"Tool {name} failed after {duration:.2f}s") return [TextContent( type="text", text=json.dumps({ "status": "error", "error": str(e), "tool": name, "timestamp": datetime.utcnow().isoformat() }) )] def _extract_context(self, arguments: Dict[str, Any]) -> RequestContext: """Extract request context from arguments""" user_id = arguments.pop("_user_id", "anonymous") session_id = arguments.pop("_session_id", None) metadata = arguments.pop("_metadata", {}) return RequestContext( user_id=user_id, session_id=session_id, metadata=metadata ) def _validate_arguments(self, arguments: Dict[str, Any], schema: Dict[str, Any]): """Validate tool arguments against schema""" # Basic validation - can be extended with pydantic input_schema = schema.get("inputSchema", {}) required = input_schema.get("required", []) properties = input_schema.get("properties", {}) # Check required fields for field in required: if field not in arguments: raise ValueError(f"Missing required field: {field}") # Validate field types for field, value in arguments.items(): if field in properties: field_schema = properties[field] expected_type = field_schema.get("type") if expected_type == "string" and not isinstance(value, str): raise ValueError(f"Field {field} must be a string") elif expected_type == "integer" and not isinstance(value, int): raise ValueError(f"Field {field} must be an integer") elif expected_type == "array" and not isinstance(value, list): raise ValueError(f"Field {field} must be an array") # Check enum values if "enum" in field_schema and value not in field_schema["enum"]: raise ValueError(f"Field {field} must be one of {field_schema['enum']}") def _is_cacheable(self, tool_name: str) -> bool: """Determine if tool result should be cached""" # Non-mutating operations are cacheable non_mutating = ["get", "list", "search", "find", "read"] return any(op in tool_name.lower() for op in non_mutating) async def _execute_tool(self, handler: Callable, arguments: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """Execute tool handler with error handling""" try: # Pass context to handler if it accepts it import inspect sig = inspect.signature(handler) if 'context' in sig.parameters: result = await handler(arguments, context=context) else: result = await handler(arguments) return result except Exception as e: logger.error(f"Tool handler failed: {str(e)}") return { "status": "error", "error": str(e), "timestamp": datetime.utcnow().isoformat() } async def run(self): """Start the MCP server""" logger.info(f"Starting MCP server: {self.config.name}") async with stdio_server() as (read_stream, write_stream): await self.server.run( read_stream, write_stream, InitializationOptions( server_name=self.config.name, server_version=self.config.version, capabilities=self.server.get_capabilities( notification_options=NotificationOptions(), experimental_capabilities={}, ) ) ) def tool( name: Optional[str] = None, description: str = "", input_schema: Optional[Dict[str, Any]] = None ): """Decorator for registering MCP tools""" def decorator(func): tool_name = name or func.__name__ schema = { "description": description or func.__doc__ or "", "inputSchema": input_schema or {} } # Store schema on function for later registration func._mcp_tool_schema = schema func._mcp_tool_name = tool_name return func return decorator ``` ## 2. Database Integration Patterns ```python # mcp_server/database.py """ Generic Database Integration for MCP Servers Supports multiple ORMs and connection patterns """ import asyncio from abc import ABC, abstractmethod from contextlib import asynccontextmanager from typing import Any, Dict, List, Optional, TypeVar, Generic, Union from datetime import datetime import json from sqlalchemy import create_engine, MetaData, Table, Column, Integer, String, DateTime, Text, Boolean, select, update, delete, insert from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker from sqlalchemy.orm import sessionmaker, declarative_base from sqlalchemy.pool import NullPool import asyncpg import motor.motor_asyncio from redis.asyncio import Redis # Type variables T = TypeVar('T') class DatabaseBackend(ABC): """Abstract base for database backends""" @abstractmethod async def connect(self): """Establish connection""" pass @abstractmethod async def disconnect(self): """Close connection""" pass @abstractmethod async def execute_query(self, query: str, params: Dict[str, Any] = None) -> List[Dict[str, Any]]: """Execute a query and return results""" pass @abstractmethod async def execute_command(self, command: str, params: Dict[str, Any] = None) -> Any: """Execute a command (INSERT, UPDATE, DELETE)""" pass class PostgresBackend(DatabaseBackend): """PostgreSQL backend using asyncpg""" def __init__(self, connection_string: str): self.connection_string = connection_string self.pool: Optional[asyncpg.Pool] = None async def connect(self): self.pool = await asyncpg.create_pool( self.connection_string, min_size=5, max_size=20, command_timeout=60 ) async def disconnect(self): if self.pool: await self.pool.close() async def execute_query(self, query: str, params: Dict[str, Any] = None) -> List[Dict[str, Any]]: async with self.pool.acquire() as conn: rows = await conn.fetch(query, *params.values() if params else []) return [dict(row) for row in rows] async def execute_command(self, command: str, params: Dict[str, Any] = None) -> Any: async with self.pool.acquire() as conn: return await conn.execute(command, *params.values() if params else []) class SQLAlchemyBackend(DatabaseBackend): """SQLAlchemy backend for multiple databases""" def __init__(self, database_url: str, async_mode: bool = True): self.database_url = database_url self.async_mode = async_mode self.engine = None self.session_factory = None async def connect(self): if self.async_mode: self.engine = create_async_engine( self.database_url, pool_pre_ping=True, pool_recycle=300, echo=False ) self.session_factory = async_sessionmaker( self.engine, class_=AsyncSession, expire_on_commit=False ) else: self.engine = create_engine( self.database_url, pool_pre_ping=True, pool_recycle=300, echo=False ) self.session_factory = sessionmaker( bind=self.engine, expire_on_commit=False ) async def disconnect(self): if self.engine: await self.engine.dispose() @asynccontextmanager async def get_session(self): """Get database session""" async with self.session_factory() as session: try: yield session if self.async_mode: await session.commit() else: session.commit() except Exception: if self.async_mode: await session.rollback() else: session.rollback() raise finally: if self.async_mode: await session.close() else: session.close() async def execute_query(self, query: Any, params: Dict[str, Any] = None) -> List[Dict[str, Any]]: """Execute SQLAlchemy query""" async with self.get_session() as session: if isinstance(query, str): # Raw SQL query result = await session.execute(query, params or {}) rows = result.fetchall() return [dict(row._mapping) for row in rows] else: # SQLAlchemy ORM query result = await session.execute(query) rows = result.fetchall() return [dict(row._mapping) for row in rows] async def execute_command(self, command: Any, params: Dict[str, Any] = None) -> Any: """Execute SQLAlchemy command""" async with self.get_session() as session: if isinstance(command, str): # Raw SQL command result = await session.execute(command, params or {}) await session.commit() return result else: # SQLAlchemy ORM command await session.execute(command, params or {}) await session.commit() return None class MongoBackend(DatabaseBackend): """MongoDB backend using motor""" def __init__(self, connection_string: str, database_name: str): self.connection_string = connection_string self.database_name = database_name self.client = None self.db = None async def connect(self): self.client = motor.motor_asyncio.AsyncIOMotorClient(self.connection_string) self.db = self.client[self.database_name] async def disconnect(self): if self.client: self.client.close() async def execute_query(self, collection: str, query: Dict[str, Any] = None) -> List[Dict[str, Any]]: """Execute MongoDB find query""" cursor = self.db[collection].find(query or {}) results = [] async for document in cursor: # Convert ObjectId to string if '_id' in document: document['_id'] = str(document['_id']) results.append(document) return results async def execute_command(self, operation: str, collection: str, data: Dict[str, Any]) -> Any: """Execute MongoDB command""" if operation == "insert": result = await self.db[collection].insert_one(data) return str(result.inserted_id) elif operation == "update": filter_ = data.pop("_filter") update_data = {"$set": data} result = await self.db[collection].update_one(filter_, update_data) return result.modified_count elif operation == "delete": result = await self.db[collection].delete_one(data) return result.deleted_count class DatabaseManager(Generic[T]): """Generic database manager for MCP servers""" def __init__(self, backend: DatabaseBackend): self.backend = backend self._connected = False async def connect(self): """Connect to database""" if not self._connected: await self.backend.connect() self._connected = True async def disconnect(self): """Disconnect from database""" if self._connected: await self.backend.disconnect() self._connected = False @asynccontextmanager async def transaction(self): """Database transaction context manager""" if hasattr(self.backend, 'get_session'): async with self.backend.get_session() as session: yield session else: # For backends that don't support transactions yield self.backend async def find_one(self, table_or_collection: str, query: Dict[str, Any]) -> Optional[Dict[str, Any]]: """Find a single record""" if isinstance(self.backend, MongoBackend): results = await self.backend.execute_query(table_or_collection, query) return results[0] if results else None else: # SQL implementation where_clause = " AND ".join([f"{k} = :{k}" for k in query.keys()]) sql = f"SELECT * FROM {table_or_collection} WHERE {where_clause} LIMIT 1" results = await self.backend.execute_query(sql, query) return results[0] if results else None async def find_many( self, table_or_collection: str, query: Dict[str, Any] = None, limit: int = None, offset: int = None, order_by: str = None ) -> List[Dict[str, Any]]: """Find multiple records""" query = query or {} if isinstance(self.backend, MongoBackend): cursor = self.backend.db[table_or_collection].find(query) if limit: cursor = cursor.limit(limit) if offset: cursor = cursor.skip(offset) if order_by: # MongoDB sort format sort_field, sort_dir = order_by.split() cursor = cursor.sort([(sort_field, 1 if sort_dir == 'ASC' else -1)]) results = [] async for document in cursor: if '_id' in document: document['_id'] = str(document['_id']) results.append(document) return results else: # SQL implementation where_clause = "" if query: where_clause = "WHERE " + " AND ".join([f"{k} = :{k}" for k in query.keys()]) sql = f"SELECT * FROM {table_or_collection} {where_clause}" if order_by: sql += f" ORDER BY {order_by}" if limit: sql += f" LIMIT {limit}" if offset: sql += f" OFFSET {offset}" return await self.backend.execute_query(sql, query) async def create(self, table_or_collection: str, data: Dict[str, Any]) -> Any: """Create a new record""" data = data.copy() # Add timestamps data['created_at'] = datetime.utcnow() data['updated_at'] = datetime.utcnow() if isinstance(self.backend, MongoBackend): return await self.backend.execute_command("insert", table_or_collection, data) else: # SQL implementation columns = list(data.keys()) placeholders = [f":{col}" for col in columns] sql = f"INSERT INTO {table_or_collection} ({', '.join(columns)}) VALUES ({', '.join(placeholders)})" return await self.backend.execute_command(sql, data) async def update(self, table_or_collection: str, query: Dict[str, Any], data: Dict[str, Any]) -> int: """Update records""" data = data.copy() data['updated_at'] = datetime.utcnow() if isinstance(self.backend, MongoBackend): data['_filter'] = query return await self.backend.execute_command("update", table_or_collection, data) else: # SQL implementation where_clause = " AND ".join([f"{k} = :{k}" for k in query.keys()]) set_clause = ", ".join([f"{k} = :update_{k}" for k in data.keys()]) # Prefix update params to avoid conflicts update_params = {f"update_{k}": v for k, v in data.items()} params = {**query, **update_params} sql = f"UPDATE {table_or_collection} SET {set_clause} WHERE {where_clause}" result = await self.backend.execute_command(sql, params) return result.rowcount if hasattr(result, 'rowcount') else 0 async def delete(self, table_or_collection: str, query: Dict[str, Any]) -> int: """Delete records""" if isinstance(self.backend, MongoBackend): return await self.backend.execute_command("delete", table_or_collection, query) else: # SQL implementation where_clause = " AND ".join([f"{k} = :{k}" for k in query.keys()]) sql = f"DELETE FROM {table_or_collection} WHERE {where_clause}" result = await self.backend.execute_command(sql, query) return result.rowcount if hasattr(result, 'rowcount') else 0 async def count(self, table_or_collection: str, query: Dict[str, Any] = None) -> int: """Count records""" query = query or {} if isinstance(self.backend, MongoBackend): return await self.backend.db[table_or_collection].count_documents(query) else: # SQL implementation where_clause = "" if query: where_clause = "WHERE " + " AND ".join([f"{k} = :{k}" for k in query.keys()]) sql = f"SELECT COUNT(*) as count FROM {table_or_collection} {where_clause}" results = await self.backend.execute_query(sql, query) return results[0]['count'] if results else 0 # Factory function for creating database managers def create_database_manager(database_url: str, backend_type: str = "auto") -> DatabaseManager: """Create database manager based on URL or backend type""" if backend_type == "auto": if database_url.startswith("postgresql+asyncpg://"): backend = SQLAlchemyBackend(database_url, async_mode=True) elif database_url.startswith("mongodb://"): import re match = re.match(r'mongodb://[^/]+/([^?]*)', database_url) db_name = match.group(1) if match else "default" backend = MongoBackend(database_url, db_name) elif database_url.startswith("postgresql://"): backend = PostgresBackend(database_url) else: backend = SQLAlchemyBackend(database_url, async_mode=True) else: if backend_type == "postgres": backend = PostgresBackend(database_url) elif backend_type == "mongodb": db_name = database_url.split("/")[-1].split("?")[0] backend = MongoBackend(database_url, db_name) elif backend_type == "sqlalchemy": backend = SQLAlchemyBackend(database_url) else: raise ValueError(f"Unknown backend type: {backend_type}") return DatabaseManager(backend) ``` ## 3. Tool Implementation Patterns ```python # mcp_server/tools.py """ Generic MCP Tool Implementation Patterns """ from typing import Any, Dict, List, Optional, Union, Callable from datetime import datetime, timedelta import json import uuid from dataclasses import dataclass, field from .core import BaseMCPServer, tool, RequestContext from .database import DatabaseManager class BaseTool: """Base class for MCP tools""" def __init__(self, db_manager: DatabaseManager, cache=None): self.db_manager = db_manager self.cache = cache async def execute(self, args: Dict[str, Any], context: RequestContext = None) -> Dict[str, Any]: """Execute the tool logic""" raise NotImplementedError def _validate_permissions(self, context: RequestContext, required_permission: str = None) -> bool: """Validate user permissions""" # Implement permission checking logic return True class CRUDBaseTool(BaseTool): """Base CRUD tool for any entity""" def __init__(self, table_name: str, db_manager: DatabaseManager, schema: Dict[str, Any]): super().__init__(db_manager) self.table_name = table_name self.schema = schema self.entity_name = table_name.rstrip('s') # Remove plural 's' async def create(self, args: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """Create entity""" try: # Validate against schema validated_data = self._validate_data(args, for_create=True) # Add user context if context: validated_data['user_id'] = context.user_id if context.session_id: validated_data['session_id'] = context.session_id # Insert into database result = await self.db_manager.create(self.table_name, validated_data) return { "status": "created", "id": result, "entity": self.entity_name, "timestamp": datetime.utcnow().isoformat() } except Exception as e: return { "status": "error", "error": str(e), "entity": self.entity_name, "operation": "create" } async def get(self, args: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """Get entity by ID""" try: entity_id = args.get("id") if not entity_id: raise ValueError("Missing required field: id") # Add user filter for security query = {"id": entity_id} if context and not self._validate_permissions(context, "read_all"): query["user_id"] = context.user_id result = await self.db_manager.find_one(self.table_name, query) if not result: return { "status": "not_found", "entity": self.entity_name, "id": entity_id } return { "status": "success", "entity": self.entity_name, "data": self._serialize_data(result) } except Exception as e: return { "status": "error", "error": str(e), "entity": self.entity_name, "operation": "get" } async def list(self, args: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """List entities with filtering""" try: # Build query from args query = {} filters = args.get("filters", {}) limit = args.get("limit", 20) offset = args.get("offset", 0) order_by = args.get("order_by", "created_at DESC") # Add user filter for security if context and not self._validate_permissions(context, "read_all"): query["user_id"] = context.user_id # Apply additional filters query.update(filters) # Fetch from database results = await self.db_manager.find_many( self.table_name, query=query, limit=limit, offset=offset, order_by=order_by ) # Get total count total = await self.db_manager.count(self.table_name, query) return { "status": "success", "entity": self.entity_name, "data": [self._serialize_data(r) for r in results], "pagination": { "total": total, "limit": limit, "offset": offset, "has_more": offset + limit < total } } except Exception as e: return { "status": "error", "error": str(e), "entity": self.entity_name, "operation": "list" } async def update(self, args: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """Update entity""" try: entity_id = args.pop("id", None) if not entity_id: raise ValueError("Missing required field: id") # Validate update data update_data = self._validate_data(args, for_create=False) # Build query filter query = {"id": entity_id} if context and not self._validate_permissions(context, "update_all"): query["user_id"] = context.user_id # Update in database affected = await self.db_manager.update(self.table_name, query, update_data) if affected == 0: return { "status": "not_found", "entity": self.entity_name, "id": entity_id } return { "status": "updated", "entity": self.entity_name, "id": entity_id, "affected_rows": affected, "timestamp": datetime.utcnow().isoformat() } except Exception as e: return { "status": "error", "error": str(e), "entity": self.entity_name, "operation": "update" } async def delete(self, args: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """Delete entity""" try: entity_id = args.get("id") if not entity_id: raise ValueError("Missing required field: id") # Build query filter query = {"id": entity_id} if context and not self._validate_permissions(context, "delete_all"): query["user_id"] = context.user_id # Delete from database affected = await self.db_manager.delete(self.table_name, query) if affected == 0: return { "status": "not_found", "entity": self.entity_name, "id": entity_id } return { "status": "deleted", "entity": self.entity_name, "id": entity_id, "affected_rows": affected, "timestamp": datetime.utcnow().isoformat() } except Exception as e: return { "status": "error", "error": str(e), "entity": self.entity_name, "operation": "delete" } def _validate_data(self, data: Dict[str, Any], for_create: bool = False) -> Dict[str, Any]: """Validate data against schema""" validated = {} schema_fields = self.schema.get("properties", {}) required_fields = self.schema.get("required", []) # Check required fields for create if for_create: for field in required_fields: if field not in data: raise ValueError(f"Missing required field: {field}") # Validate each field for field, value in data.items(): if field not in schema_fields: continue # Skip unknown fields or raise error based on strictness field_schema = schema_fields[field] field_type = field_schema.get("type") # Type validation if field_type == "string": if not isinstance(value, str): raise ValueError(f"Field {field} must be a string") # Check min/max length if "minLength" in field_schema and len(value) < field_schema["minLength"]: raise ValueError(f"Field {field} is too short") if "maxLength" in field_schema and len(value) > field_schema["maxLength"]: raise ValueError(f"Field {field} is too long") elif field_type == "integer": if not isinstance(value, int): raise ValueError(f"Field {field} must be an integer") # Check min/max value if "minimum" in field_schema and value < field_schema["minimum"]: raise ValueError(f"Field {field} is too small") if "maximum" in field_schema and value > field_schema["maximum"]: raise ValueError(f"Field {field} is too large") elif field_type == "array": if not isinstance(value, list): raise ValueError(f"Field {field} must be an array") # Check enum values if "enum" in field_schema and value not in field_schema["enum"]: raise ValueError(f"Field {field} must be one of {field_schema['enum']}") validated[field] = value return validated def _serialize_data(self, data: Dict[str, Any]) -> Dict[str, Any]: """Serialize data for output""" serialized = data.copy() # Handle datetime serialization for key, value in serialized.items(): if isinstance(value, datetime): serialized[key] = value.isoformat() elif isinstance(value, dict): # Convert complex types to JSON string try: json.dumps(value) except TypeError: serialized[key] = str(value) return serialized class BulkOperationTool(BaseTool): """Tool for bulk operations on entities""" def __init__(self, table_name: str, db_manager: DatabaseManager, schema: Dict[str, Any]): super().__init__(db_manager) self.table_name = table_name self.schema = schema self.entity_name = table_name.rstrip('s') async def bulk_create(self, args: Dict[str, Any], context: RequestContext) -> Dict[str, Any]: """Bulk create entities""" try: items = args.get("items", []) if not items: raise ValueError("No items provided for bulk create") # Validate all items validated_items = [] for item in items: validated = self._validate_item(item) if context: validated["user_id"] = context.user_id validated_items.append(validated) # Insert all items results = [] for item in validated_items: result = await self.db_manager.create(self.table_name, item) results.append(result) return { "status": "created", "entity": self.entity_name, "count": len(results), …(truncated)