microsoft/playwright · error · Error

Command is required

Error message

Command is required

What it means

Thrown by `parseCliCommand` when `commands[args._[0]]` is falsy, i.e. the first positional argument does not match any registered CLI command name. This covers both an empty argument list and an unrecognized command name.

Source

Thrown at packages/playwright-core/src/tools/cli-daemon/daemon.ts:147

async function deleteSessionFile(clientInfo: ClientInfo, sessionConfig: SessionConfig) {
  await fs.promises.unlink(sessionConfig.socketPath).catch(() => {});
  if (!sessionConfig.cli.persistent) {
    const sessionFile = path.join(clientInfo.daemonProfilesDir, `${sessionConfig.name}.session`);
    await fs.promises.rm(sessionFile).catch(() => {});
  }
}

function formatResult(result: CallToolResult) {
  const isError = result.isError;
  const text = result.content[0].type === 'text' ? result.content[0].text : undefined;
  return { isError, text };
}

function parseCliCommand(args: Record<string, string> & { _: string[] }): { toolName: string, toolParams: NonNullable<CallToolRequest['params']['arguments']> } {
  const command = commands[args._[0]];
  if (!command)
    throw new Error('Command is required');
  return parseCommand(command, args);
}

function daemonSocketPath(clientInfo: ClientInfo, sessionName: string): string {
  return makeSocketPath('cli', `${clientInfo.workspaceDirHash}-${sessionName}`);
}

function createSessionConfig(clientInfo: ClientInfo, sessionName: string, browserInfo: BrowserInfo, options: {
  ownership?: 'attached' | 'own',
  persistent?: boolean,
  exitOnStop?: boolean,
} = {}): SessionConfig {
  return {
    name: sessionName,
    version: clientInfo.version,
    timestamp: Date.now(),
    socketPath: daemonSocketPath(clientInfo, sessionName),
    workspaceDir: clientInfo.workspaceDir,

View on GitHub (pinned to c8fc3bf8d3)

Solutions

1. Ensure `params.args._[0]` is a valid command name (e.g. `click`, `fill`, `screenshot`, `drop`).
2. If unsure of available commands, list them from the commands registry / `--help` output.
3. Check that argument parsing in the client preserves positional args in `_` (yargs-style) rather than dropping them.

Example fix

// before
{ args: { _: [], target: 'ref' } }
// after
{ args: { _: ['click'], target: 'ref' } }

// Ensure a command name is present and recognized before sending.
const KNOWN_COMMANDS = new Set(['click', 'fill', 'hover', 'screenshot', 'drop', /* ... */]);
function buildRunArgs(positional: string[]) {
  if (!positional.length || !KNOWN_COMMANDS.has(positional[0]))
    throw new TypeError(`Unknown or missing command: ${positional[0] ?? '(none)'}`);
  return { _: positional };
}

function hasCommand(args: { _: string[] }): args is { _: [string, ...string[]] } {
  return args._.length > 0;
}

When it happens

Trigger: Invoking the daemon `run` method with `params.args._` being empty, or with a first element that is not a registered command (e.g. a typo, an internal-only name, or a command removed in this version).

Common situations: Client sends a bare `run` with no command (e.g. just flags); user types a command name that doesn't exist (`'sreenshot'`); version mismatch where a command was renamed; a wrapper script that strips the command token before forwarding.

Related errors

• --data must be in "mime/type=value" format, got: ${entry}
• boolean option '--${key}' should not be passed with '=value'
• Could not start the session "${sessionName}"
• Client is v${clientInfo.version}, session '${this.name}' is
• Browser '${this.name}' is not open. Run playwright-cli${t

AI-assisted analysis of microsoft/playwright@c8fc3bf8d3 (2026-08-12). Data as JSON: /api/errors/3aea21ce42f29707. Report an issue: GitHub.