Jupyter notebook cell ID matching fails when using edit_cell with full source code

[tofunori]

Bug Report: Jupyter notebook cell ID matching fails with edit_cell

Problem Description

When attempting to edit Jupyter notebook cells using the mcp__jupyter__edit_cell tool, the cell ID matching consistently fails even when using the exact cell source code as returned by read_notebook_source_only.

Steps to Reproduce

1. Read a notebook using mcp__jupyter__read_notebook_source_only
2. Copy the exact cell source code from the output (including the first comment line)
3. Attempt to edit that cell using mcp__jupyter__edit_cell with the copied source as cell_id
4. The operation fails with "No cell found with ID [exact_source_code]"

Expected Behavior

The cell should be found and edited successfully when using the exact source code as returned by the read operation.

Actual Behavior

No cell found with ID # August-only spatial visualization with UltraPlot (FIXED)
import ultraplot as uplt
[... rest of source code ...]

Example Case

• Notebook: netcdf_reader.ipynb
• Cell to edit: Last cell with comment # August-only spatial visualization with UltraPlot (FIXED)
• Read output shows: Cell exists with that exact source code
• Edit attempt: Fails to find the cell

Attempted Workarounds

1. ✅ Used just the comment line: # August-only spatial visualization with UltraPlot (FIXED) - Still failed
2. ✅ Used truncated comment: Same failure
3. ✅ Used manual Python JSON manipulation: This worked as a workaround

Successful Workaround

import json
with open('notebook.ipynb', 'r') as f:
    nb = json.load(f)
# Direct manipulation of nb['cells'][-1]['source']

Impact

• Makes programmatic notebook editing very difficult
• Forces users to resort to manual JSON manipulation
• Breaks the expected workflow of read → edit cycle
• Inconsistent behavior between read and edit operations

Environment

• Tool: mcp__jupyter__edit_cell
• Context: Claude Code CLI
• Notebook format: Standard Jupyter .ipynb

Suggested Fix

The cell ID matching algorithm should be more robust and handle:

1. Exact source code matching (current behavior seems broken)
2. Partial matching for comments/headers
3. Position-based indexing as fallback
4. Better error messages indicating what cell IDs are available

This issue significantly impacts the usability of Jupyter notebook editing capabilities.