bash
Execute shell commands directly from Claude Code MCP to perform system operations, manage files, and run scripts within the development environment.
Instructions
Execute a shell command
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| command | Yes | The shell command to execute | |
| timeout | No | Optional timeout in milliseconds (max 600000) |
Implementation Reference
- src/server/tools.ts:19-51 (handler)The handler function for the bash tool. It checks for banned commands, calls executeCommand helper, formats response, and handles errors.
async ({ command, timeout }) => { try { // Check for banned commands const bannedCommands = [ 'alias', 'curl', 'curlie', 'wget', 'axel', 'aria2c', 'nc', 'telnet', 'lynx', 'w3m', 'links', 'httpie', 'xh', 'http-prompt', 'chrome', 'firefox', 'safari' ]; const commandParts = command.split(' '); if (bannedCommands.includes(commandParts[0])) { return { content: [{ type: "text", text: `Error: The command '${commandParts[0]}' is not allowed for security reasons.` }], isError: true }; } const result = await executeCommand(command, timeout); return { content: [{ type: "text", text: result }] }; } catch (error) { return { content: [{ type: "text", text: error instanceof Error ? error.message : String(error) }], isError: true }; } } - src/server/tools.ts:15-18 (schema)Input schema for the bash tool using Zod: command (string) and optional timeout (number).
{ command: z.string().describe("The shell command to execute"), timeout: z.number().optional().describe("Optional timeout in milliseconds (max 600000)") }, - src/server/tools.ts:12-52 (registration)Registration of the bash tool on the MCP server using server.tool().
server.tool( "bash", "Execute a shell command", { command: z.string().describe("The shell command to execute"), timeout: z.number().optional().describe("Optional timeout in milliseconds (max 600000)") }, async ({ command, timeout }) => { try { // Check for banned commands const bannedCommands = [ 'alias', 'curl', 'curlie', 'wget', 'axel', 'aria2c', 'nc', 'telnet', 'lynx', 'w3m', 'links', 'httpie', 'xh', 'http-prompt', 'chrome', 'firefox', 'safari' ]; const commandParts = command.split(' '); if (bannedCommands.includes(commandParts[0])) { return { content: [{ type: "text", text: `Error: The command '${commandParts[0]}' is not allowed for security reasons.` }], isError: true }; } const result = await executeCommand(command, timeout); return { content: [{ type: "text", text: result }] }; } catch (error) { return { content: [{ type: "text", text: error instanceof Error ? error.message : String(error) }], isError: true }; } } ); - src/utils/bash.ts:12-24 (helper)Helper function that executes the shell command using Node's child_process.exec.
export async function executeCommand(command: string, timeout?: number): Promise<string> { try { const options = timeout ? { timeout } : {}; const { stdout, stderr } = await execPromise(command, options); if (stderr) { console.error(`Command stderr: ${stderr}`); } return stdout; } catch (error) { console.error(`Error executing command: ${command}`, error); throw error; } }