import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { fetchHtml } from "../utils.js";
import { FindPatternsArgs, LinkResult } from "../types-and-interfaces.js";
import { McpError, ErrorCode } from "@modelcontextprotocol/sdk/types.js";
/**
* Tool that finds all links that match a given pattern
*
* @param server - MCP server instance to register the tool with
*/
export const findPatternsTool = (server: McpServer): void => {
server.tool(
"find-patterns",
"Find all links that match a given pattern",
{
url: z.string().url(),
pattern: z.string(),
},
async (args: FindPatternsArgs, extra) => {
try {
const { $ } = await fetchHtml(args.url);
const matches: LinkResult[] = [];
const regex = new RegExp(args.pattern);
$('a[href]').each((_, element) => {
const link = $(element);
const href = link.attr('href');
const text = link.text().trim();
if (href) {
try {
const fullUrl = new URL(href, args.url).toString();
if (regex.test(fullUrl)) {
matches.push({
url: fullUrl,
text: text || '[No text]'
});
}
} catch (e) {
// Skip invalid URLs
}
}
});
return {
content: [
{
type: "text",
text: JSON.stringify(matches, null, 2)
}
]
};
} catch (error) {
const errorMessage = error instanceof Error ? error.message : 'Unknown error occurred';
throw new McpError(ErrorCode.InternalError, `Error finding patterns: ${errorMessage}`);
}
}
)
}