import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { z } from 'zod';
import { spawn } from 'child_process';
export const shellProgram = '/usr/bin/bash';
export const toolName = 'execute-bash-script-async';
export const toolDescription = `This tool executes shell scripts asynchronously in bash.
Executing each command creates a new bash process.
Synchronous execution requires to wait the scripts completed.
Asynchronous execution makes it possible to execute multiple scripts in parallel.
You can reduce waiting time by planning in advance which shell scripts need to be executed and executing them in parallel.
Avoid using execute-bash-script-sync tool unless you really need to, and use this execute-bash-script-async tool whenever possible.
`;
export interface CommandOptions {
cwd?: string;
env?: Record<string, string>;
timeout?: number;
outputMode?: 'complete' | 'line' | 'character' | 'chunk';
onOutput?: (data: string, isStderr: boolean) => void;
}
export const toolOptionsDefaults = {
outPutMode: 'complete' as NonNullable<CommandOptions['outputMode']>,
};
export const toolOptionsSchema = {
command: z.string().describe('The bash script to execute'),
options: z.object({
cwd: z.string().optional().describe(`The working directory to execute the script.
use this option argument to avoid cd command in the first line of the script.
\`~\` and environment variable is not supported. use absolute path instead.
`),
env: z.record(z.string(), z.string()).optional()
.describe(`The environment variables for the script.
Set environment variables using this option instead of using export command in the script.
`),
timeout: z.number().int().positive().optional().describe(`The timeout in milliseconds.
Set enough long timeout even if you don't need to set timeout to avoid unexpected blocking.
`),
outputMode: z
.enum(['complete', 'line', 'character', 'chunk'])
.optional()
.default(toolOptionsDefaults.outPutMode).describe(`The output mode for the script.
- complete: Notify when the command is completed
- line: Notify on each line of output
- chunk: Notify on each chunk of output
- character: Notify on each character of output
`),
}),
};
export interface CommandResult {
exitCode: number;
}
/**
* シェルスクリプト出力ハンドリング関数
*/
function handleOutput(
chunk: string,
isStderr: boolean,
outputMode: CommandOptions['outputMode'],
onOutput: CommandOptions['onOutput'] | undefined,
buffer: { current: string }, // バッファのコピーを回避
) {
if (onOutput) {
if (outputMode === 'character') {
// 文字ごとに通知
for (const char of chunk) {
onOutput(char, isStderr);
}
} else if (outputMode === 'line') {
// 行ごとに通知
buffer.current += chunk;
const lines = buffer.current.split('\n'); // 改行で分割
const lastLine = lines.pop(); // 最後の行を取得
for (const line of lines) {
onOutput(line + '\n', isStderr); // 改行を追加して通知
}
if (lastLine !== undefined && chunk.endsWith('\n')) {
// 最後のデータが改行で終わっている場合は通知
onOutput(lastLine + '\n', isStderr);
buffer.current = ''; // バッファをクリア
} else {
// 最後のデータが改行で終わっていない場合は、バッファに保持
buffer.current = lastLine || ''; // 未完成の行を保持
}
} else if (outputMode === 'chunk') {
// チャンク（データ受信単位）ごとに通知
onOutput(chunk, isStderr);
} else if (outputMode === 'complete') {
// complete モードでは通知なし
buffer.current += chunk;
} else {
// 想定外の outputMode の場合に例外をスロー
throw new Error(`Unsupported outputMode: ${outputMode}`);
}
}
}
/**
* 柔軟な出力モードをサポートするコマンド実行関数
*/
export async function executeCommand(
command: string,
options: CommandOptions = {},
): Promise<CommandResult> {
const outputMode = (options as CommandOptions).outputMode || toolOptionsDefaults.outPutMode;
const onOutput = options.onOutput;
return new Promise((resolve, reject) => {
// 環境変数を設定
const env = {
...process.env,
...options.env,
};
// bashプロセスを起動
const bash = spawn(shellProgram, [], {
cwd: options.cwd,
env,
stdio: ['pipe', 'pipe', 'pipe'],
});
const stdoutBuffer = { current: '' }; // バッファのコピーを回避
const stderrBuffer = { current: '' }; // バッファのコピーを回避
let timeoutId: NodeJS.Timeout | null = null;
const flushBuffer = () => {
if (onOutput) {
if (stdoutBuffer.current) {
onOutput(stdoutBuffer.current, false);
stdoutBuffer.current = ''; // バッファをクリア
}
if (stderrBuffer.current) {
onOutput(stderrBuffer.current, true);
stderrBuffer.current = ''; // バッファをクリア
}
}
};
// 標準出力の処理
bash.stdout.on('data', (data) => {
handleOutput(data.toString(), false, outputMode, onOutput, stdoutBuffer);
});
// 標準エラー出力の処理
bash.stderr.on('data', (data) => {
handleOutput(data.toString(), true, outputMode, onOutput, stderrBuffer);
});
// タイムアウト処理
if (options.timeout) {
timeoutId = setTimeout(() => {
bash.kill();
reject(new Error(`Command timed out after ${options.timeout}ms`));
}, options.timeout);
}
// プロセス終了時の処理
bash.on('close', (code) => {
// タイマーをクリア
if (timeoutId) clearTimeout(timeoutId);
// バッファをフラッシュ
flushBuffer();
// NOTE これは MCP サーバの実装であるので、ログは標準エラー出力に出す
console.error('bash process exited with code', code);
resolve({
exitCode: code !== null ? code : 1,
});
});
bash.on('error', (error) => {
// タイマーをクリア
if (timeoutId) clearTimeout(timeoutId);
// バッファをフラッシュ
flushBuffer();
// NOTE これは MCP サーバの実装であるので、ログは標準エラー出力に出す
console.error('Failed to start bash process:', error);
reject(error);
});
// コマンドを標準入力に書き込み、EOF を送信
bash.stdin.write(command + '\n');
bash.stdin.end();
});
}
// MCPサーバーにコマンド実行ツールを追加する関数
export function setTool(mcpServer: McpServer) {
// McpServerインスタンスから低レベルのServerインスタンスにアクセスする
const server: Server = mcpServer.server;
// 単一のツールとして登録
mcpServer.tool(
toolName,
toolDescription,
toolOptionsSchema,
// eslint-disable-next-line @typescript-eslint/no-unused-vars
async ({ command, options = {} }, extra) => {
try {
// outputModeを取得、デフォルト値は'complete'
const outputMode = options?.outputMode || 'complete';
// 進捗トークンを生成
const progressToken = `cmd-${Date.now()}-${Math.random().toString(36).slice(2, 7)}`;
const onOutput = (data: string, isStderr: boolean) => {
const fsMark = isStderr ? 'stderr' : 'stdout';
server.notification({
method: 'notifications/tools/progress',
params: {
progressToken,
result: {
content: [
{
type: 'text' as const,
text: `${fsMark}: ${data}`,
},
],
isComplete: false,
},
},
});
};
// バックグラウンドでコマンドを実行
executeCommand(command, {
...options,
onOutput,
})
.then(({ exitCode }) => {
// 完了通知を送信
server.notification({
method: 'notifications/tools/progress',
params: {
progressToken,
result: {
content: [
{
type: 'text' as const,
text: `exitCode: ${exitCode}`,
},
],
isComplete: true,
},
},
});
})
.catch((error) => {
// エラー通知を送信
server.notification({
method: 'notifications/tools/progress',
params: {
progressToken,
result: {
content: [
{
type: 'text' as const,
text: `Error: ${error instanceof Error ? error.message : String(error)}`,
},
],
isComplete: true,
isError: true,
},
},
});
});
// 初期レスポンスを返す
return {
content: [
{
type: 'text' as const,
text: `# Command execution started with output mode, ${outputMode}`,
},
],
progressToken,
};
} catch (error) {
return {
content: [
{
type: 'text' as const,
text: `Error: ${error instanceof Error ? error.message : String(error)}`,
},
],
isError: true,
};
}
},
);
}