rename-files-date-prefix

name	rename-files-date-prefix
description	Renames all files in a SharePoint document library (including subfolders) to prefix them with their created date in yyMMdd format (e.g., 251203-Status Report.pdf). Offers a preview before committing changes. Use when the user asks to prefix filenames with dates or add date prefixes to files.

Rename Files with Date Prefix

Rename all files in a SharePoint document library to prefix them with their created date in yyMMdd format (e.g., 251203-Status Report.pdf).

Steps

1. Identify the Target Library

• Use the current document library if the user doesn't specify one.
• Call get_current_list_or_library to get the library ID.

2. Get the Library Schema

• Call get_list_schema to confirm the library has Created and FileLeafRef fields and to understand the structure.

3. Retrieve All Files (Including Subfolders)

• Call get_list_item_metadata with fetchAll: true to retrieve all items.
• Use a CAML query that filters to files only (FSObjType = 0):

  <Query><Where><Eq><FieldRef Name='FSObjType'/><Value Type='Integer'>0</Value></Eq></Where><OrderBy><FieldRef Name='FileLeafRef' Ascending='TRUE'/></OrderBy></Query>
  

4. Build the Preview

For each file returned:

1. Extract the Created date and format it as yyMMdd (2-digit year, 2-digit month, 2-digit day).
2. Get the current filename from FileLeafRef.
3. Determine the folder path from FileRef (strip the filename to get the folder).
4. Skip check: If the filename already matches the pattern ^\d{6}- (six digits followed by a hyphen), mark it as skipped with reason "Already has date prefix".
5. Build the new filename: yyMMdd-OriginalFilename.

5. Show the Preview Table

Always show the preview before making any changes. Present a markdown table:

#	Current Name	New Name	Folder	Status
1	Status Report.pdf	251203-Status Report.pdf	/sites/Team/Docs	Will rename
2	251203-Budget.xlsx	251203-Budget.xlsx	/sites/Team/Docs/Finance	Skipped (already prefixed)

Include a summary:

• Total files found: X
• To be renamed: Y
• Skipped: Z

Then ask: "Ready to rename Y files? Confirm to proceed."

6. Rename on Confirmation

Once the user confirms:

• For each file to be renamed, call update_list_items with:
  • itemId: the file's list item ID
  • fieldInternalNames: ["FileLeafRef"]
  • newValues: ["yyMMdd-OriginalFilename"]
• Process files one at a time to handle errors gracefully.
• If a rename fails, log the error and continue with the remaining files.

7. Report Results

After processing, show a summary:

• Successfully renamed: X files
• Skipped (already prefixed): Y files
• Errors: Z files (list the filenames and error details)

Date Formatting Rules

• Use the file's Created date (not Modified).
• Format: yyMMdd — 2-digit year, 2-digit month (zero-padded), 2-digit day (zero-padded).
• Example: December 3, 2025 → 251203
• Example: January 15, 2024 → 240115
• Time zone: SharePoint returns Created in UTC. Format the prefix from the site's regional time zone, not raw UTC, so a file uploaded at 23:30 local time keeps its local-day date. If the site time zone cannot be determined, fall back to UTC and tell the user once in the preview header ("Dates are formatted in UTC — set the site regional settings to use local time.").

Edge Cases

• Already prefixed files: Skip any file whose name starts with 6 digits followed by a hyphen (^\d{6}-).
• Folders: Never rename folders — only process items where FSObjType = 0.
• Subfolders: Process files in all subfolders recursively (use fetchAll: true).
• Duplicate names after prefixing: If the proposed yyMMdd-Name already exists in the same folder, do not rename and do not overwrite. Mark the file as Skipped (name collision) in the preview / results with the conflicting target name shown. Never append numeric suffixes (-1, -2) to disambiguate — the user must resolve the conflict manually. The other files in the batch still rename.
• Special characters: Preserve the original filename exactly as-is after the prefix.
• Empty libraries: If no files match the CAML query, tell the user the library has no files to rename and stop — do not show an empty preview table.

Resuming after a mid-batch failure

Long runs can be interrupted — throttling, network drop, the user closing the chat. The skill must be safe to re-run from scratch without any extra bookkeeping:

• The ^\d{6}- skip check automatically excludes every file that was successfully renamed in the previous run. Re-running picks up exactly where the failure stopped.
• If a file failed mid-rename (rare — SharePoint renames are atomic), it will still match the original name and be processed again in the next run.
• Do not keep an external "already processed" list, lock file, or marker column. The filename itself is the source of truth.
• After a partial run, the Step 7 results report must clearly distinguish Renamed, Skipped (already prefixed), Skipped (name collision), and Errors so the user can decide whether to re-run.

Example

User: "Prefix all files in this library with their created date"

Agent response (preview):

#	Current Name	New Name	Folder	Status
1	Quarterly Review.docx	250915-Quarterly Review.docx	/sites/Team/Reports	Will rename
2	241101-Notes.pdf	241101-Notes.pdf	/sites/Team/Reports	Skipped (already prefixed)
3	Budget.xlsx	250301-Budget.xlsx	/sites/Team/Finance	Will rename

Total files: 3 | To rename: 2 | Skipped: 1

Ready to rename 2 files? Confirm to proceed.

Constraints

• Never rename without showing the preview first.
• Never rename folders.
• Never double-prefix files.
• Never append numeric suffixes to resolve name collisions — mark as Skipped (name collision) instead.
• Always process errors gracefully — one failure should not stop the entire batch. Safe to re-run; the ^\d{6}- skip check protects already-renamed files (see Resuming after a mid-batch failure).