csv-column-renamer

name

csv-column-renamer

description

Rename one or more columns in a CSV file in place or to a new path, keeping row order and cell values untouched. Use when the user points at a specific CSV (by path, filename, or pasted content) and asks to rename / relabel / change the header of one or more columns, including requests like "change the column `foo` to `bar`", "the header says revenue but should say sales", or "make these column names snake_case". Do NOT trigger for general CSV editing (row filtering, deduplication, type coercion), for creating a new CSV, for Excel `.xlsx` files, or when the user has not identified which column to rename.

CSV Column Renamer

When to use

Trigger only when all three are true:

1. The user has identified a specific CSV file (path, filename, or pasted content).
2. The user wants to change one or more column names, not cell contents.
3. The format is CSV (not .xlsx, not a database table).

If the user wants to filter rows, change values, or convert types, decline and suggest a different tool.

Workflow

1. Confirm the target file path and the exact old → new column mappings. If any mapping is ambiguous (e.g. two columns both called id), ask exactly once which one they mean.
2. Read the file's header row only.
3. Verify every "old name" exists in the header. If any is missing, stop and list the actual header so the user can correct the mapping.
4. Produce the new header by substituting names positionally; do not reorder columns.
5. Write the output:
   • If the user said "in place", overwrite the original file.
   • Otherwise, write to the path the user specified, or to <original>.renamed.csv if unspecified.
6. Report the diff: old_header → new_header and the output path.

Output format

Always return:

Renamed <N> column(s) in <path>:
  <old_1> → <new_1>
  <old_2> → <new_2>
  ...
Output: <output_path>

Failure handling

• Missing old column name → stop, print actual header, ask for correction.
• File not found → stop, ask for the correct path.
• File is .xlsx or has no header row → decline with one-line reason.
• Ambiguous duplicate header → ask which occurrence to rename.

Safety

• Never modify cell data.
• Never reorder columns.
• When overwriting in place, keep a .bak copy next to the original.