LLDB MCP Server

Instructions

Can disassemble:
- A named function: 'main', 'MyClass::method'
- An address range: '0x1000-0x1100' or '0x1000 0x1100'
- Current frame (when stopped at breakpoint)

Options:
- show_bytes: Include raw opcode bytes
- mixed: Interleave source code with assembly

Args:
    params: DisassembleInput with target and display options

Returns:
    str: Assembly listing

Implementation Reference

• lldb_mcp_server.py:721-766 (handler)

  Main handler function that constructs and executes LLDB 'disassemble' commands based on input parameters, supporting functions, addresses, ranges, with options for showing bytes and mixed source+asm.

  async def lldb_disassemble(params: DisassembleInput) -> str:
      """Disassemble machine code to view assembly instructions.
  
      Can disassemble:
      - A named function: 'main', 'MyClass::method'
      - An address range: '0x1000-0x1100' or '0x1000 0x1100'
      - Current frame (when stopped at breakpoint)
  
      Options:
      - show_bytes: Include raw opcode bytes
      - mixed: Interleave source code with assembly
  
      Args:
          params: DisassembleInput with target and display options
  
      Returns:
          str: Assembly listing
      """
      commands = [f"target create {params.executable}"]
  
      dis_cmd = "disassemble"
  
      if "-" in params.target and params.target.startswith("0x"):
          # Address range
          parts = params.target.split("-")
          dis_cmd += f" --start-address {parts[0]} --end-address {parts[1]}"
      elif params.target.startswith("0x"):
          # Single address
          dis_cmd += f" --start-address {params.target} --count 50"
      elif params.target.lower() == "current":
          dis_cmd += " --frame"
      else:
          # Function name
          dis_cmd += f" --name {params.target}"
  
      if params.show_bytes:
          dis_cmd += " --bytes"
      if params.mixed:
          dis_cmd += " --mixed"
  
      commands.append(dis_cmd)
  
      result = _run_lldb_script(commands)
  
      return f"## Disassembly: `{params.target}`\n\n```asm\n{result['output'].strip()}\n```"

• lldb_mcp_server.py:243-256 (schema)

  Pydantic input model validating parameters: executable path, disassembly target (function/address/'current'), flags for bytes and mixed mode.

  class DisassembleInput(BaseModel):
      """Input for disassembling code."""
  
      model_config = ConfigDict(str_strip_whitespace=True)
  
      executable: str = Field(..., description="Path to the executable", min_length=1)
      target: str = Field(
          ...,
          description="What to disassemble: function name, address range (e.g., '0x1000-0x1100'), or 'current' for current frame",
          min_length=1,
      )
      show_bytes: bool = Field(default=False, description="Show opcode bytes alongside instructions")
      mixed: bool = Field(default=False, description="Show mixed source and assembly")

• lldb_mcp_server.py:711-720 (registration)

  MCP tool registration decorator specifying the tool name and annotations for read-only, non-destructive behavior.

  @mcp.tool(
      name="lldb_disassemble",
      annotations={
          "title": "Disassemble Code",
          "readOnlyHint": True,
          "destructiveHint": False,
          "idempotentHint": True,
          "openWorldHint": False,
      },
  )