LLDB MCP Server

Instructions

Can display:
- Source around a specific line
- Source for a named function
- Source at the current debug position

Args:
    params: ListSourceInput specifying what source to show

Returns:
    str: Source code listing with line numbers

Implementation Reference

• lldb_mcp_server.py:924-955 (handler)

  The handler function executes LLDB source listing commands based on the provided input parameters and formats the output as markdown.

  async def lldb_source(params: ListSourceInput) -> str:
      """List source code for a file, function, or current location.
  
      Can display:
      - Source around a specific line
      - Source for a named function
      - Source at the current debug position
  
      Args:
          params: ListSourceInput specifying what source to show
  
      Returns:
          str: Source code listing with line numbers
      """
      commands = [f"target create {params.executable}"]
  
      if params.function:
          commands.append(f"source list --name {params.function} --count {params.count}")
      elif params.file and params.line:
          commands.append(
              f"source list --file {params.file} --line {params.line} --count {params.count}"
          )
      elif params.file:
          commands.append(f"source list --file {params.file} --count {params.count}")
      else:
          commands.append(f"source list --count {params.count}")
  
      result = _run_lldb_script(commands)
  
      title = params.function or params.file or "Source"
      return f"## {title}\n\n```cpp\n{result['output'].strip()}\n```"

• lldb_mcp_server.py:318-330 (schema)

  Pydantic input model defining parameters for the lldb_source tool: executable path, optional file/line/function, and line count.

  class ListSourceInput(BaseModel):
      """Input for listing source code."""
  
      model_config = ConfigDict(str_strip_whitespace=True)
  
      executable: str = Field(..., description="Path to the executable", min_length=1)
      file: str | None = Field(
          default=None, description="Source file to list (if None, lists around current location)"
      )
      line: int | None = Field(default=None, description="Line number to center on", ge=1)
      count: int = Field(default=20, description="Number of lines to show", ge=1, le=500)
      function: str | None = Field(default=None, description="Show source for a specific function")

• lldb_mcp_server.py:914-923 (registration)

  MCP tool registration decorator that registers the lldb_source handler with metadata annotations.

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