[BUG] JupyterNotebook new cell constantly inserted at the beginning of a notebook

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: <!-- output of claude --version -->
• Operating System: Linux 6.8.0-64-generic
• Terminal: <!-- e.g. iTerm2, Terminal App -->

## Bug Description
The NotebookEdit tool with edit_mode="insert" inserts cells at the beginning of
the notebook instead of at the end when no cell_id is specified, contrary to
expected behavior.

## Steps to Reproduce

1. Open a Jupyter notebook with multiple cells using NotebookEdit
2. Use NotebookEdit with edit_mode="insert" and cell_type="code" without

specifying a cell_id parameter

1. Observe where the new cell is inserted

## Expected Behavior
When using edit_mode="insert" without specifying a cell_id, the new cell
should be inserted at the end of the notebook (as the last cell).

## Actual Behavior
The new cell is inserted at the beginning of the notebook (as the first cell)
instead of at the end.

## Additional Context

• Workaround: Must specify the cell_id of the last cell to insert after it
• This affects user experience when trying to add cells to the end of notebooks

during analysis workflows

• The tool documentation suggests that omitting cell_id should insert at the

beginning, but user expectation is that "insert" without position means "append to
end"

Duplicate of: https://github.com/anthropics/claude-code/issues/2925