Cells

edit_cell_source

Perform a surgical find-and-replace within a cell's source (like an editor's Edit tool).

Perform a surgical find-and-replace within a cell's source (like an editor's Edit tool). Finds old_string in the cell and replaces it with new_string. Matching is literal (not regex) and may span multiple lines. By default, old_string must appear exactly once; set replace_all=True for multiple occurrences. Returns a diff of the changes made.

Prefer this over overwrite_cell_source for small, targeted edits — it is safer because unchanged parts of the cell are left untouched. Use read_cell first to see the current source and construct an accurate old_string.

destructive: yes · idempotent: no · open-world: no

Parameters

ParameterTypeRequiredDefaultDescription
cell_indexinteger | nullnonullIndex of the cell to edit (0-based). Omit when passing cell_id.
old_stringstringyes—Exact string to find in cell source
new_stringstringyes—Replacement string
replace_allbooleannofalseReplace all occurrences (default: first only)
notebook_namestring | nullnonullTarget this specific connected notebook instead of the currently activated one. Use when multiple clients share this server, to avoid racing the shared 'current notebook' pointer. Omit to use the currently activated notebook.
cell_idstring | nullnonullAddress the cell by its notebook cell id instead of its index. An index is a position, and a position stops being true the moment anyone inserts a cell above it; an id does not. Every result says which id it acted on, so read a cell once and address it by id afterwards. Given both, the id wins.

Output

{
  "properties": {
    "kind": {
      "description": "What this result is — 'cell.read', 'notebooks.list' and so on. Lets a client tell one answer from another without matching prose.",
      "title": "Kind",
      "type": "string"
    },
    "result": {
      "default": null,
      "description": "The answer itself: a message, the rows of a listing, or the outputs of an execution in order.",
      "title": "Result"
    }
  },
  "required": [
    "kind"
  ],
  "type": "object",
  "additionalProperties": true,
  "description": "What every tool of this server answers with.\n\nDeclared so the shape is *advertised* rather than merely produced. A tool\nthat returns structure without saying what it will return leaves a client\nnothing to validate against and the generated reference nothing to show —\nthe call works and the contract is invisible, which is the worst of both.\n\nExtra fields are allowed on purpose. A tool that already answers with a\nmapping keeps its own keys (see :func:`_default_shape`), and those are the\ninteresting part of its answer; forbidding them would mean either\nflattening every tool into one shape or declaring nothing at all.",
  "title": "ToolAnswer"
}

Call it

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "edit_cell_source",
    "arguments": {
      "cell_index": null,
      "old_string": "<old_string>",
      "new_string": "<new_string>",
      "replace_all": false,
      "notebook_name": null,
      "cell_id": null
    }
  }
}
result = await session.call_tool("edit_cell_source", arguments={"cell_index": None, "old_string": "<old_string>", "new_string": "<new_string>", "replace_all": False, "notebook_name": None, "cell_id": None})

Source

Registered by the @mcp.tool decorator on edit_cell_source in jupyter_mcp_server/server.py.

Built withSourcey