Step 1: Detect backed-up patches

Check for local patches directory:

Global install (path templated at install time)

PATCHES_DIR={{PLATFORM_ROOT}}/gsd-local-patches

Local install fallback

if [ ! -d "$PATCHES_DIR" ]; then PATCHES_DIR={{PLATFORM_ROOT}}/gsd-local-patches fi

Read backup-meta.json from the patches directory.

If no patches found:

No local patches found. Nothing to reapply.

Local patches are automatically saved when you run {{COMMAND_PREFIX}}update after modifying any GSD workflow, command, or agent files.

Exit.

Step 2: Show patch summary

Local Patches to Reapply

Backed up from: v{from_version} Current version: {read VERSION file} Files modified: {count}

Step 3: Merge each file

For each file in backup-meta.json :

Read the backed-up version (user's modified copy from gsd-local-patches/ )

Read the newly installed version (current file after update)

Compare and merge:

• If the new file is identical to the backed-up file: skip (modification was incorporated upstream)

• If the new file differs: identify the user's modifications and apply them to the new version

Merge strategy:

• Read both versions fully

• Identify sections the user added or modified (look for additions, not just differences from path replacement)

• Apply user's additions/modifications to the new version

• If a section the user modified was also changed upstream: flag as conflict, show both versions, ask user which to keep

Write merged result to the installed location

Report status:

• Merged — user modifications applied cleanly

• Skipped — modification already in upstream

• Conflict — user chose resolution

Step 4: Update manifest

After reapplying, regenerate the file manifest so future updates correctly detect these as user modifications:

The manifest will be regenerated on next {{COMMAND_PREFIX}}update

For now, just note which files were modified

Step 5: Cleanup option

Ask user:

• "Keep patch backups for reference?" → preserve gsd-local-patches/

• "Clean up patch backups?" → remove gsd-local-patches/ directory

Step 6: Report

Patches Reapplied

{count} file(s) updated. Your local modifications are active again.

<success_criteria>

• All backed-up patches processed

• User modifications merged into new version

• Conflicts resolved with user input

• Status reported for each file </success_criteria>