write_memory

Instructions

Write data to memory address.

Args:
    address: Memory address (hex string like "0x401234")
    data: Data to write (hex string, or value if value_type specified)
    value_type: Type of data ("bytes", "int32", "float", "string", etc.)

Returns:
    Write status.

Implementation Reference

• src/frida_game_hacking_mcp/server.py:638-691 (handler)

  The handler function decorated with @mcp.tool() that executes the write_memory tool. It validates attachment, parses and packs the data into bytes, injects a Frida JavaScript script to perform the memory write using Memory.writeByteArray, and returns success status with details.

  @mcp.tool()
  def write_memory(address: str, data: str, value_type: str = "bytes") -> Dict[str, Any]:
      """
      Write data to memory address.
      
      Args:
          address: Memory address (hex string like "0x401234")
          data: Data to write (hex string, or value if value_type specified)
          value_type: Type of data ("bytes", "int32", "float", "string", etc.)
      
      Returns:
          Write status.
      """
      global _session
      
      if not _session.is_attached():
          return {"error": "Not attached. Use attach() first."}
      
      try:
          addr = int(address, 16) if address.startswith("0x") else int(address)
          
          if value_type == "bytes":
              write_bytes = bytes.fromhex(data.replace(" ", ""))
          elif value_type in ("int8", "uint8", "int16", "uint16", "int32", "uint32",
                             "int64", "uint64", "float", "double"):
              value = float(data) if value_type in ("float", "double") else int(data)
              write_bytes = _pack_value(value, value_type)
          elif value_type == "string":
              write_bytes = data.encode('utf-8') + b'\x00'
          else:
              write_bytes = bytes.fromhex(data.replace(" ", ""))
          
          byte_array = ", ".join(f"0x{b:02x}" for b in write_bytes)
          script_code = f"""
          var addr = ptr("{hex(addr)}");
          Memory.writeByteArray(addr, [{byte_array}]);
          send("done");
          """
          
          script = _session.session.create_script(script_code)
          script.on('message', lambda m, d: None)
          script.load()
          script.unload()
          
          return {
              "success": True,
              "address": hex(addr),
              "bytes_written": len(write_bytes),
              "data_hex": write_bytes.hex()
          }
      
      except Exception as e:
          return {"error": f"Failed to write memory: {str(e)}"}

• src/frida_game_hacking_mcp/server.py:139-154 (helper)

  Supporting utility function used by write_memory to convert typed values (int*, uint*, float, double, string) into little-endian byte arrays using struct.pack.

  def _pack_value(value: Any, value_type: str) -> bytes:
      """Pack value to bytes based on type."""
      formats = {
          "int8": "<b", "uint8": "<B",
          "int16": "<h", "uint16": "<H",
          "int32": "<i", "uint32": "<I",
          "int64": "<q", "uint64": "<Q",
          "float": "<f", "double": "<d"
      }
      fmt = formats.get(value_type)
      if fmt:
          return struct.pack(fmt, value)
      elif value_type == "string":
          return value.encode('utf-8') + b'\x00'
      return struct.pack("<i", int(value))

• src/frida_game_hacking_mcp/server.py:195-198 (registration)

  The write_memory tool is listed under memory_operations category in the list_capabilities tool response, indicating its availability.

  "memory_operations": [
      "read_memory", "write_memory", "scan_value", "scan_next",
      "scan_changed", "scan_unchanged", "scan_pattern",
      "get_scan_results", "clear_scan", "list_memory_regions"

• src/frida_game_hacking_mcp/server.py:640-649 (schema)

  Docstring defining the input parameters and return type for the write_memory tool, serving as schema documentation.

  """
  Write data to memory address.
  
  Args:
      address: Memory address (hex string like "0x401234")
      data: Data to write (hex string, or value if value_type specified)
      value_type: Type of data ("bytes", "int32", "float", "string", etc.)
  
  Returns:
      Write status.