secure_random_int

Instructions

Implementation Reference

• src/random_number_mcp/tools.py:139-158 (handler)

  Core implementation of secure_random_int. Uses secrets.randbelow() to generate a cryptographically secure random integer in [0, upper_bound). Validates upper_bound is a positive integer.

  def secure_random_int(upper_bound: int) -> int:
      """Generate a secure random integer below upper_bound.
  
      Args:
          upper_bound: Upper bound (exclusive)
  
      Returns:
          Random integer in range [0, upper_bound)
  
      Raises:
          ValueError: If upper_bound <= 0
          TypeError: If upper_bound is not an integer
      """
      if not isinstance(upper_bound, int):
          raise TypeError("upper_bound must be an integer")
  
      if upper_bound <= 0:
          raise ValueError("upper_bound must be positive")
  
      return secrets.randbelow(upper_bound)

• src/random_number_mcp/server.py:112-122 (handler)

  MCP tool registration wrapper for secure_random_int. Decorated with @app.tool() to expose it as an MCP tool. Delegates to tools.secure_random_int().

  @app.tool()
  def secure_random_int(upper_bound: int) -> int:
      """Generate a secure random integer below upper_bound.
  
      Args:
          upper_bound: Upper bound (exclusive)
  
      Returns:
          Random integer in range [0, upper_bound)
      """
      return tools.secure_random_int(upper_bound)

• src/random_number_mcp/server.py:112-122 (registration)

  Registration of secure_random_int as an MCP tool via the @app.tool() decorator on the server handler function.

  @app.tool()
  def secure_random_int(upper_bound: int) -> int:
      """Generate a secure random integer below upper_bound.
  
      Args:
          upper_bound: Upper bound (exclusive)
  
      Returns:
          Random integer in range [0, upper_bound)
      """
      return tools.secure_random_int(upper_bound)

• src/random_number_mcp/server.py:113-119 (schema)

  Input schema defined by the type hint 'upper_bound: int' in the tool registration, which FastMCP uses to generate the JSON schema for the tool.

  def secure_random_int(upper_bound: int) -> int:
      """Generate a secure random integer below upper_bound.
  
      Args:
          upper_bound: Upper bound (exclusive)
  
      Returns:

• src/random_number_mcp/utils.py:1-35 (helper)

  Utility functions used by tools.py (validate_range, validate_positive_int, etc.) — though secure_random_int does its own inline validation rather than using these helpers.

  """Utility functions for the random number MCP server."""
  
  from typing import Any
  
  
  def validate_range(low: int | float, high: int | float) -> None:
      """Validate that low <= high for range-based functions."""
      if low > high:
          raise ValueError(f"Low value ({low}) must be <= high value ({high})")
  
  
  def validate_positive_int(value: int, name: str) -> None:
      """Validate that a value is a positive integer."""
      if not isinstance(value, int):
          raise TypeError(f"{name} must be an integer, got {type(value).__name__}")
      if value < 0:
          raise ValueError(f"{name} must be non-negative, got {value}")
  
  
  def validate_list_not_empty(items: list[Any], name: str) -> None:
      """Validate that a list is not empty."""
      if not items:
          raise ValueError(f"{name} cannot be empty")
  
  
  def validate_weights_match_population(
      population: list[Any], weights: list[int | float]
  ) -> None:
      """Validate that weights list matches population length."""
      if len(weights) != len(population):
          raise ValueError(
              f"Weights list length ({len(weights)}) must match "
              f"population length ({len(population)})"
          )