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

# 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

# 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

# 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),
           

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