import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { ErrorCode, McpError } from '@modelcontextprotocol/sdk/types.js';
import type { HandlerContext } from '../../../handlers/interfaces.js';
import type {
HandlerEntry,
IHandlerGroup,
ToolHandler,
} from '../interfaces.js';
import { jsonSchemaToZod } from '../utils/schemaUtils.js';
/**
* Base class for handler groups
* Provides common functionality for registering handlers
*/
export abstract class BaseHandlerGroup implements IHandlerGroup {
protected abstract groupName: string;
protected context: HandlerContext;
constructor(context: HandlerContext) {
this.context = context;
}
/**
* Gets the name of the handler group
*/
getName(): string {
return this.groupName;
}
/**
* Gets all handler entries in this group
* Must be implemented by subclasses
*/
abstract getHandlers(): HandlerEntry[];
/**
* Registers all handlers from this group on the MCP server
*/
registerHandlers(server: McpServer): void {
const handlers = this.getHandlers();
for (const entry of handlers) {
this.registerToolOnServer(
server,
entry.toolDefinition.name,
entry.toolDefinition.description,
entry.toolDefinition.inputSchema,
entry.handler,
);
}
}
/**
* Helper function to register a tool on McpServer
* Wraps handler to convert our response format to MCP format
*/
protected registerToolOnServer(
server: McpServer,
toolName: string,
description: string,
inputSchema: any,
handler: ToolHandler,
): void {
// Convert JSON Schema to Zod if needed, otherwise pass as-is
const zodSchema =
inputSchema &&
typeof inputSchema === 'object' &&
inputSchema.type === 'object' &&
inputSchema.properties
? jsonSchemaToZod(inputSchema)
: inputSchema;
server.registerTool(
toolName,
{
description,
inputSchema: zodSchema,
},
async (args: any) => {
const result = await handler(this.context, args);
// If error, throw it
if (result.isError) {
const errorText =
result.content
?.map((item: any) => {
if (item?.type === 'json' && item.json !== undefined) {
return JSON.stringify(item.json);
}
return item?.text || String(item);
})
.join('\n') || 'Unknown error';
throw new McpError(ErrorCode.InternalError, errorText);
}
// Convert content to MCP format - JSON items become text
const content = (result.content || []).map((item: any) => {
if (item?.type === 'json' && item.json !== undefined) {
return {
type: 'text' as const,
text: JSON.stringify(item.json),
};
}
return {
type: 'text' as const,
text: item?.text || String(item || ''),
};
});
return { content };
},
);
}
}
