feat(tools): add get_random_words tool with Fisher-Yates shuffle

helpers/shuffle.ts

@@ -0,0 +1,11 @@
+const fishersYatesShuffle = <Type>(arr: Type[]): Type[] => {
+  const shuffled = [...arr]
+  for (let index = shuffled.length - 1; index > 0; index--) {
+    const secondIndex = Math.floor(Math.random() * (index + 1))
+    // biome-ignore lint/style/noNonNullAssertion: indices are guaranteed to be valid in Fisher-Yates shuffle
+    ;[shuffled[index]!, shuffled[secondIndex]!] = [shuffled[secondIndex]!, shuffled[index]!]
+  }
+  return shuffled
+}
+
+export default fishersYatesShuffle

services/randomWord.ts

@@ -0,0 +1,5 @@
+import fishersYatesShuffle from "@/helpers/shuffle"
+
+export const getRandomWords = (words: string[], count: number) => {
+  return fishersYatesShuffle(words).slice(0, count)
+}

stdio.ts

@@ -1,6 +1,7 @@
 import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js"
 import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"
 import { registerDictionariesFunctionality } from "@/resources/dictionaries"
+import { addRandomWordsTool } from "./tools/getRandomWords"
 
 const server = new McpServer({
   name: "writer-helpers",
@@ -8,6 +9,7 @@ const server = new McpServer({
 })
 
 registerDictionariesFunctionality(server)
+addRandomWordsTool(server)
 
 const transport = new StdioServerTransport()
 await server.connect(transport)

tools/getRandomWords.ts

@@ -0,0 +1,36 @@
+import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js"
+import z from "zod"
+import { readDictionary } from "@/services/dictionaries"
+import { getRandomWords } from "@/services/randomWord"
+
+export const addRandomWordsTool = (server: McpServer) => {
+  server.registerTool(
+    "get_random_words",
+    {
+      title: "Get Random Words",
+      description: "Get a list of random words from a dictionary.",
+      inputSchema: z.object({
+        dictionary: z.string(),
+        count: z.number().optional().default(1)
+      })
+    },
+    async (input) => {
+      try {
+        const words: string[] = (await readDictionary(input.dictionary)).split("\n")
+
+        return { content: [{ type: "text", text: getRandomWords(words, input.count).join("\n") }] }
+      } catch (error) {
+        if (error instanceof Error) {
+          return {
+            isError: true,
+            content: []
+          }
+        }
+        return {
+          isError: true,
+          content: []
+        }
+      }
+    }
+  )
+}