{
  "approach": "Modify the `_perturb_models` property to handle tuple step_size by computing half_step per dimension, or normalize step_size to always be a float by using the first dimension's step when it's a tuple. Looking at the tests, they expect 16 jobs/models with tuple (2,2,4) steps, so the code needs to iterate over dimensions properly.\n\nPlanner dropped nonexistent files: [\"autofit/non_linear/grid/sensitivity.py\"]",
  "files_to_edit": [],
  "finish_reason": "stop",
  "hypothesis": "The issue is in the `_perturb_models` property of the Sensitivity class. The `step_size` property can return a tuple when `number_of_steps` is a tuple, but the code does `self.limit_scale * self.step_size / 2` which fails because you can't divide a tuple by an int. The fix needs to handle tuple step_size in `_perturb_models`.",
  "retries": {},
  "usage": {
    "completion": 189,
    "prompt": 11037,
    "reasoning": 0
  }
}