Class: Nanobot::Agent::Tools::Exec

Inherits:
RubyLLM::Tool
  • Object
show all
Defined in:
lib/nanobot/agent/tools/shell.rb

Overview

Tool for executing shell commands.

IMPORTANT: The DENY_PATTERNS list below is accident prevention, not a security boundary. It catches common destructive typos and mistakes but is trivially bypassed (nested shells, alternative interpreters, creative flag combinations, data exfiltration via curl/wget, etc.). For actual isolation, use OS-level sandboxing (bubblewrap, containers).

Constant Summary collapse

DENY_PATTERNS =

Common destructive patterns blocked as accident prevention. NOT a security boundary — see class comment above.

[
  /rm\s+-rf/i,
  %r{rmdir\s+/s}i,
  /format\s/i,
  /mkfs/i,
  /shutdown/i,
  /reboot/i,
  /halt/i,
  /poweroff/i,
  /dd\s+if=/i,
  /:\(\)\{\s*:\|:&\s*\};:/, # fork bomb
  %r{>/dev/sd[a-z]}i # writing to disk devices
].freeze

Instance Method Summary collapse

Constructor Details

#initialize(working_dir: nil, timeout: 60, restrict_to_workspace: false) ⇒ Exec

Returns a new instance of Exec.

Parameters:

  • working_dir (String, nil) (defaults to: nil) —

    directory to run commands in (defaults to cwd)

  • timeout (Integer) (defaults to: 60) —

    maximum seconds before a command is killed

  • restrict_to_workspace (Boolean) (defaults to: false) —

    when true, block commands referencing paths outside working_dir



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# File 'lib/nanobot/agent/tools/shell.rb', line 40

def initialize(working_dir: nil, timeout: 60, restrict_to_workspace: false)
  super()
  @working_dir = working_dir ? Pathname.new(working_dir).expand_path.to_s : Dir.pwd
  @timeout = timeout
  @restrict_to_workspace = restrict_to_workspace
end

Instance Method Details

#execute(command:) ⇒ String

Execute a shell command and return its combined output.

Parameters:

  • command (String) —

    shell command to execute

Returns:

  • (String) —

    formatted output with exit code, stdout, and stderr



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# File 'lib/nanobot/agent/tools/shell.rb', line 50

def execute(command:)
  # Accident prevention: block common destructive patterns
  return 'Error: Command blocked — matches a known destructive pattern.' if dangerous?(command)

  # Best-effort workspace restriction.
  # NOTE: This is NOT a true security boundary.
  # Shell commands can bypass this check via aliases, symlinks, subshells, etc.  For
  # stronger isolation, use containers or OS-level sandboxing.
  if @restrict_to_workspace && command_leaves_workspace?(command)
    return "Error: Command appears to access paths outside the workspace (#{@working_dir}). " \
           'Restricted to workspace directory.'
  end

  begin
    # Execute command with timeout
    stdout, stderr, status = execute_with_timeout(command)

    # Format output
    output = []
    output << "Exit code: #{status.exitstatus}"

    if stdout && !stdout.empty?
      output << "\nStdout:"
      output << stdout
    end

    if stderr && !stderr.empty?
      output << "\nStderr:"
      output << stderr
    end

    output.join("\n")
  rescue Timeout::Error
    "Error: Command timed out after #{@timeout} seconds"
  rescue StandardError => e
    "Error executing command: #{e.message}"
  end
end