refactor tool implementation

mcp/shared.ts

@@ -4,6 +4,15 @@ import type { StandardSchemaV1 } from "@standard-schema/spec";
 import type { FastMCP, Tool } from "fastmcp";
 import { parseRepoContext, type RepoContext } from "../utils/github.ts";
 
+export interface ToolResult {
+  content: {
+    type: "text";
+    text: string;
+  }[];
+  error?: string;
+  isError?: boolean;
+}
+
 export const getMcpContext = cached((): McpContext => {
   const githubInstallationToken = process.env.GITHUB_INSTALLATION_TOKEN;
   if (!githubInstallationToken) {
@@ -30,3 +39,40 @@ export const addTools = (server: FastMCP, tools: Tool<any, any>[]) => {
   }
   return server;
 };
+
+export const contextualize =
+  <T>(executor: (params: T, ctx: McpContext) => Promise<Record<string, any>>) =>
+  async (params: T): Promise<ToolResult> => {
+    try {
+      const ctx = getMcpContext();
+      const result = await executor(params, ctx);
+      return handleToolSuccess(result);
+    } catch (error) {
+      return handleToolError(error);
+    }
+  };
+
+const handleToolSuccess = (data: Record<string, any>): ToolResult => {
+  return {
+    content: [
+      {
+        type: "text",
+        text: JSON.stringify(data, null, 2),
+      },
+    ],
+  };
+};
+
+const handleToolError = (error: unknown): ToolResult => {
+  const errorMessage = error instanceof Error ? error.message : String(error);
+  return {
+    content: [
+      {
+        type: "text",
+        text: `Error: ${errorMessage}`,
+      },
+    ],
+    error: errorMessage,
+    isError: true,
+  };
+};