Register llm tools and their implementation function.

tools.ts

import { exec } from 'child_process';

import * as vscode from 'vscode';
export function registerChatTools(context: vscode.ExtensionContext) {
  context.subscriptions.push(vscode.lm.registerTool("runScript", new RunInTerminalTool()));
}

interface IRunInTerminalParameters {
	command: string;
}
export class RunInTerminalTool
	implements vscode.LanguageModelTool<IRunInTerminalParameters> {
	async invoke(
		options: vscode.LanguageModelToolInvocationOptions<IRunInTerminalParameters>,
		_token: vscode.CancellationToken
	) {
		const params = options.input as IRunInTerminalParameters;
    try{
			// When starting the server, create a new terminal
			if (params.command.includes("start") || params.command.includes("server.ts")) {
					const terminal = vscode.window.createTerminal("Copilot Terminal");
					terminal.show();
					terminal.sendText(params.command);
					return new vscode.LanguageModelToolResult([new vscode.LanguageModelTextPart("Send command to new terminal window.")]);
			}
     	// Run the command asynchronously
			const { stdout, stderr } = await execAsyncWithTimeout(params.command, 10000);
			
			return new vscode.LanguageModelToolResult([
				new vscode.LanguageModelTextPart(stdout + " " +stderr),
			]);
    }
    catch(err:any){
			return new vscode.LanguageModelToolResult([new vscode.LanguageModelTextPart(JSON.stringify(err))]);
    }
	}

	async prepareInvocation(
		options: vscode.LanguageModelToolInvocationPrepareOptions<IRunInTerminalParameters>,
		_token: vscode.CancellationToken
	) {
		const confirmationMessages = {
			title: 'Run command in terminal',
			message: new vscode.MarkdownString(
				`Run this command in a terminal?` +
				`\t${options.input.command}`
			),
		};

		return {
			confirmationMessages,
			invocationMessage: `Running command in terminal`,
		};
	}
}


async function execAsyncWithTimeout(command: string, timeout: number): Promise<{ stdout: string, stderr: string }> {
  return new Promise((resolve, reject) => {
    const child = exec(command, (error, stdout, stderr) => {
      if (error) {
        reject(`${error} ${stdout}, ${stderr}`);
      } else {
        resolve({ stdout, stderr });
      }
    });

    setTimeout(() => {
      child.kill();
      resolve({stdout:'Command timed out or successfully running over 10 seconds', stderr:''});
    }, timeout);
  });
}