flynn/src/tools/builtin/shell.ts

import { execFile } from 'child_process';
import type { Tool, ToolResult, ToolExecutionContext } from '../types.js';

interface ShellExecArgs {
  command: string;
  cwd?: string;
  timeout?: number;
}

export const shellExecTool: Tool = {
  name: 'shell.exec',
  description: 'Execute a shell command and return stdout/stderr. Use for running build commands, git operations, system tasks, etc.',
  inputSchema: {
    type: 'object',
    properties: {
      command: { type: 'string', description: 'The shell command to execute' },
      cwd: { type: 'string', description: 'Working directory (optional)' },
      timeout: { type: 'number', description: 'Timeout in milliseconds (default 30000)' },
    },
    required: ['command'],
  },
  execute: async (rawArgs: unknown, context?: ToolExecutionContext): Promise<ToolResult> => {
    const args = rawArgs as ShellExecArgs;
    const timeout = args.timeout ?? 30_000;

    return new Promise((resolve) => {
      const child = execFile('bash', ['-c', args.command], {
        cwd: args.cwd,
        timeout,
        maxBuffer: 1024 * 1024,
      }, (error, stdout, stderr) => {
        if (context?.signal) {
          context.signal.removeEventListener('abort', onAbort);
        }
        if (error) {
          if (error.killed || error.signal === 'SIGTERM') {
            resolve({ success: false, output: stdout, error: `Command timed out after ${timeout}ms` });
            return;
          }
          resolve({
            success: false,
            output: stdout,
            error: stderr || error.message,
          });
          return;
        }
        resolve({ success: true, output: stdout + (stderr ? `\nstderr: ${stderr}` : '') });
      });

      const onAbort = () => {
        child.kill('SIGTERM');
      };
      if (context?.signal) {
        if (context.signal.aborted) {
          onAbort();
        } else {
          context.signal.addEventListener('abort', onAbort, { once: true });
        }
      }
    });
  },
};